ALBERT

Description: There is a general consensus that for the next few decades at least, the Earth will continue its warming. This will inevitably bring about serious environmental problems. For human society, the most severe will be those related to alterations of the hydrological cycle, which is already heavily influenced by human activities. Climate change will directly affect groundwater recharge, groundwater quality and the freshwater-seawater interface. The variations of groundwater storage inevitably entail a variety of geomorphological and engineering effects. In the areas where water resources are likely to diminish, groundwater will be one of the main solutions to prevent drought. In spite of its paramount importance, the issue of Climate Change and Groundwater' has been neglected. This volume presents some of the current understanding of the topic.

Description: In order to estimate the influence of global climate change upon the hydrological regime, variations in the water budget prompted by precipitation and temperature changes were evaluated in the region of Campania (southern Italy). In many parts of the region, precipitation distribution in the last 20 years shows a marked reduction. During the same period, Campania also experienced a regional temperature increase of about 0.3{degrees}C. Water budgets, calculated in a geographical information system environment for the region's hydrogeological structures, show a mean decrease of 30% of average infiltration within the present climate scenario. The structures most affected are carbonate aquifers, with the flow of springs being significantly reduced (about 70 m3/s). The most severely affected zones are the mountainous areas in the southern and northern parts of Campania.

Description: Groundwater regime in Bulgaria is influenced by climate variability. The impact is evident especially for karst water. A time series analysis of spring discharge for selected karst basins was performed. The impact of the 19821994 drought period on groundwater regime was detected. For springs that drain open and mountainous karst, the impact of climate variability is similar to that on surface waters. In fact, the difference in degree of influence of the drought period is related to the specific geological structure of the karst massifs and recharge conditions. Furthermore, the porous waters are characterized by a weaker reaction to such an effect. In general, groundwater use during the 19821994 drought period was impacted by climate variability due to limited resource availability.

Description: Groundwater flow is steered by both the groundwater recharge rate and by discharge altitudes above or below sea level; it is further controlled by the hydraulic properties of the aquifer system and often contains a transient flow component affected by natural hydrologic processes. All present groundwater discharges have both recent (〈100 years) and past groundwater recharge components (〉100 years). The ratio of the present to the past groundwater recharge depends on the climate zone: it is large in humid and small in arid areas, hence at low recharge rates transient, and at high groundwater recharge rates steady-state conditions prevail. Developing groundwater management strategies while neglecting any transient response of groundwater resources, and conducted in sensitive recharge/discharge areas like dry lands, results in either over-estimates or under-estimates of safe yields of groundwater resources, and thus may lead to non-sustainable resource development. The consequence of this would be groundwater depletion and often also a deterioration of the hydraulic properties of the aquifer system by subsidence, which both take place only after a long period of time.

Description: The history of two ancient cities, Arad and Jericho, sheds light on the role of groundwater storage in deciding the survival of settlements in arid and semi-arid regions when climate changes take place. Arad, which was dependent on a local perched horizon, was deserted during the global warm periods, which spelled dryness in the Middle East. This was in spite of one of the earliest systems of artificial recharge to groundwater developed by its inhabitants. On the other hand Jericho, which depended on the supply from a perennial spring, fed by a regional aquifer, was almost continuously settled from prehistoric times to the present.

Description: In an era of increasing contest for limited water resources, the wise joint management of conventional and non-conventional water resources must be considered. Water scarcity is aggravated in coastal zones which are often characterized by high population densities and intense economic activities making heavy seasonal water demands. In this context, the use of non-conventional water increases the availability of water supplies. Non-conventional water resources of lower quality could be directed to meet additional needs. As a consequence, significantly more potable water would be available to meet human demand for safe water. Non-conventional water resources are described: waste water reclamation and reuse, and its potential application for increasing groundwater resources, as well as several practical applications.

Description: Structurally complex reservoirs form a distinct class of reservoir in which fault arrays and fracture networks, in particular, exert an overriding control on petroleum trapping and production behaviour. With modern exploration and production portfolios now commonly held in geologically complex settings, there is an increasing technical challenge to find new prospects and to extract remaining hydrocarbons from these reservoirs. This volume reviews our current understanding and ability to model the complex distribution and behaviour of fault and fracture networks, highlighting their fluid compartmentalizing effects and storage-transmissivity characteristics, and outlining approaches for predicting the dynamic fluid flow and geomechanical behaviour of these reservoirs. This collection of 25 papers provides an overview of recent progress and outstanding issues in the areas of (i) structural complexity and fault geometry, (ii) detection and prediction of faults and fractures, (iii) compartmentalizing effects of fault systems and complex siliciclastic reservoirs and (iv) critical controls affecting fractured reservoirs.

Description: Structurally complex reservoirs form a distinct class of reservoir, in which fault arrays and fracture networks, in particular, exert an over-riding control on petroleum trapping and production behaviour. With modern exploration and production portfolios commonly held in geologically complex settings, there is an increasing technical challenge to find new prospects and to extract remaining hydrocarbons from these more structurally complex reservoirs. Improved analytical and modelling techniques will enhance our ability to locate connected hydrocarbon volumes and unswept sections of reservoir, and thus help optimize field development, production rates and ultimate recovery. This volume reviews our current understanding and ability to model the complex distribution and behaviour of fault and fracture networks, highlighting their fluid compartmentalizing effects and storage-transmissivity characteristics, and outlining approaches for predicting the dynamic fluid flow and geomechanical behaviour of structurally complex reservoirs. This introductory paper provides an overview of the research status on structurally complex reservoirs and aims to create a context for the collection of papers presented in this volume and, in doing so, an entry point for the reader into the subject. We have focused on the recent progress and outstanding issues in the areas of: (i) structural complexity and fault geometry; (ii) the detection and prediction of faults and fractures; (iii) the compartmentalizing effects of fault systems and complex siliciclastic reservoirs; and (iv) the critical controls that affect fractured reservoirs.

Description: Mantle xenoliths in within-plate alkaline mafic lavas from NE Spain are mainly anhydrous spinel lherzolites and harzburgites, grading into each other, and subordinate pyroxenites. Peridotites followed an earlier melt depletion caused by mantle decompression and subsequent metasomatism. Two main types of metasomatism are differentiated affecting mainly the harzburgites: a silicate-melt metasomatism of FeTi type and a carbonatite metasomatism. Both types are recognized in the nearby Pyrenean peridotite massifs, but the presence of hydrous minerals is less frequent in the xenoliths. The two metasomatic styles could have been generated by the intrusion of Cretaceous alkaline magmas, if a chromatographic fractionationreaction process at decreasing melt mass took place. This would account for the evolution of the original alkaline silicate percolating melt towards a carbonatite-rich melt, allowing the coexistence in both space and time of the two metasomatic styles. Metasomatism in lherzolites could be explained in the same way. The pyroxenite xenoliths are interpreted as cumulates from these alkaline basic magmas that crop out in the area as rare camptonite dykes. Interaction with host lavas is minor and could explain the partial melting, enrichment and disequilibrium observed in a deformed composite xenolith and sporadic veins filled with glass.

Description: Magma generation in the Ross Sea system is related to partial melting of strongly metasomatized mantle sources where amphibole most probably plays a crucial role. In this context, metasomatism induced by a mela-nephelinite melt in lithospheric mantle of the Mt. Melbourne Volcanic Province (northern Victoria Land (NVL), Antarctica) was investigated experimentally studying the effects of melt interaction with lherzolite at 1.52.0 GPa and T=9751300 {degrees}C, and wehrlite at 1.0 GPa and T=10501250 {degrees}C. The experiments were designed to induce melt infiltration into the ultramafic rocks. The observed modifications in minerals are compared with those found in mantle xenoliths from NVL. The effects of metasomatic modifications are evaluated on the basis of run temperature, distance from the infiltrating melt and the diffusion rates of chemical components. Both in lherzolite and wehrlite, clinopyroxene exhibits large compositional variations ranging from primary diopside to high-MgCr(Na) augitic and omphacitic clinopyroxenes in lherzolite, and to low-Mg and high-TiAlFeNa augites in wehrlite. Olivine (in wehrlite) and spinel (in lherzolite) are also compositionally modified: the former shows enrichment in Fe and the latter displays a higher Cr/(Cr+Al) ratio. The systematic variations in mineral compositions imply modifications of the chemistry of the infiltrating melt as recorded by the glass veinlets and patches observed in some charges. In experiments involving wehrlite paragenesis, the glass composition approaches that of melt patches associated with both amphibole-free and amphibole-bearing natural samples, and is related to olivine + clinopyroxene crystallization coupled with primary clinopyroxene dissolution at the contact between the metasomatizing melt and the solid matrix. Even if amphibole crystallization was not attained in the experiments, we were able to explain the occurrence of amphibole in the natural system considering that in this case a hot metasomatizing melt infiltrates a cooler matrix.

Description: Mantle xenoliths entrained in late Carboniferous to mid-Permian silica-poor basic magmas from northern Scotland were investigated using major and trace element compositions of minerals and isotopic compositions of whole-rocks and clinopyroxenes. The aim of the study was to gain more precise information on the nature of the lithospheric mantle beneath this terrane, including evidence for its metasomatic modification and evolution. This study concerns peridotites from two localities in the ENE and WSW of the Scottish Northern Highlands Terrane: Rinibar (South Ronaldsay, Orkney) and Streap Com'laidh (near Glenfinnan). Two groups of clinopyroxenes can be distinguished both at Streap Com'laidh (Type-S1 and Type-S2) and Rinibar (Type-R1 and Type-R2) based on different trace element contents and isotopic ratios. Type-S1 is characterized by an almost flat profile from middle rare earth elements (MREE) to heavy REE (HREE) accompanied by an overall light REE (LREE) enrichment. It shows the highest Th and U, coupled with low Sr, Zr and TiO2 contents. Type-S2 exhibits humped LREE-enriched patterns and a steep decrease from Nd to Yb. It has the lowest Th and U, coupled with the highest Sr, TiO2 and Zr contents. Both groups of clinopyroxenes present analogous isotopic features. They have measured 87Sr/86Sr values from 0.70652 to 0.70826, 144Nd/143Nd from 0.512093 to 0.512687 and 176Hf/177Hf from 0.282727 to 0.283088. These isotopic features could be explained by the addition in the mantle wedge of a slab component, made up of altered oceanic crust plus a moderate quantity of subducted sediments. The most recent subduction event in the geological history of Scotland is at about 400 Ma. It may have been during this convergent stage that the metasomatism affecting the sub-Streap lithospheric mantle occurred. Type-R1 is characterized by the lowest concentrations of Ba, Rb, Sr, LREE and UTh, associated with remarkably high levels of Ti and Zr. These clinopyroxenes have measured 87Sr/86Sr ranging from 0.70330 to 0.70383, 144Nd/143Nd from 0.512643 to 0.512761 and 176Hf/177Hf from 0.282705 to 0.282899. In contrast, Type-R2 shows the highest concentrations of Ba, Rb, Sr, LREE and UTh, and pronounced Ti and Zr negative anomalies. They have measured 87Sr/86Sr isotopic ratios similar to Type-R1, but lower 144Nd/143Nd (0.5124310.512524) and higher 176Hf/177Hf (0.2829210.283014). Calculated melt in equilibrium with Type-R1 is very similar to inferred primary kimberlitic magmas and the clinopyroxene trace element profiles may have resulted from an efficient chemical exchange between a percolating melt and the peridotite host rock. On the other hand the calculated Type-R2 melt overlaps the field of Proterozoic carbonatites. Significantly, at the age of 550 ({+/-}50) Ma, the two groups have almost identical SrNd compositions, similar to average depleted mid-ocean ridge basalt mantle (DMM) at 550 Ma. This strongly suggests contemporaneous overprinting of DMM by kimberlitic and carbonatitic metasomatic agents at c. 550 Ma, which may be related to the opening of the Iapetus Ocean following the break-up of the Rodinia supercontinent. These data indicate a complex metasomatic history of the Scottish lithospheric mantle, which relate different geological events, most probably prior to the juxtaposition of the various tectonic blocks that nowadays constitute the Northern Highland Terranes.

Description: Landslides can consist of rotational slips, translational glide blocks, topples, talus slopes, debris flows, mudslides and compressional toes which can combine in different proportions to form complex landslides. The mass movement can be subaerial or submarine, occur over wide ranges of scale and can vary in rate from creep to catastrophic failure. Complexity of the landslide reflects the controlling factors including the strength of the deforming material and triggering mechanisms such as earthquakes, imposed load, increasing topographic relief and removal of toe material. Processes of landslide deformation include slip on discrete surfaces, distributed shear within the landslide, vertical thinning and lateral spreading through shear, fluidization, porosity collapse and loss of material from the top or toe of the complex. These processes control the quality of the resultant reservoirs. This leads to a greater range of reservoir types than conventional faulted reservoirs, with a proportionate upside and downside potential and difficulty in quantifying uncertainty. This paper uses examples from the literature, outcrops and subsurface datasets (including the Statfjord Field and the Halten Terrace in Norway) to outline the complexity of reservoirs in landslides and the challenges and opportunities in finding and producing them. We present workflows for seismic and subseismic characterization for exploration and reservoir scale based on geomorphological principles. Seismic mapping is achieved by classifying the form of the reflectors (both slip surfaces and the bounding envelope of the landslide) from an atlas of geometric and structural styles and is applied to both the Halten Terrace example and the Statfjord Field. We present a new workflow for reservoir characterization in which integration of structural, biostratigraphic, sedimentological and dynamic data gives key information on process, timing and heterogeneity of the reservoir. For the Statfjord field, important maps of the landslide block stratigraphy derived from a subcrop map and communication maps based on a c. 130 well dataset can be correlated to outcrop analogues and used to develop a predictive tool for landslide reservoir extent and quality, both in this field and others.

Description: The Penguins Cluster is a group of four oil and gas fields in the northern end of the East Shetland Basin. Its structural complexity is caused by the interaction between two or more fault trend populations, fault reactivation and the impact of faulting on the Brent reservoir architecture. This structural picture is further complicated by a NWSE trending basement lineament interpreted as a Caledonian shear zone. The present day structural configuration is the result of two Mesozoic rifting episodes and their associated thermal subsidence phases. The Permo-Triassic rifting created a number of northsouth-trending tilted fault blocks, and was followed by a period of tectonic quiescence until the Middle Jurassic, when a faulting episode coeval with the Brent Group deposition caused footwall rotation, uplift and erosion of the upper Rannoch Formation prior to the deposition of the Etive Formation across the area. The rifting climaxed in the late Jurassic, when the reactivation of pre-existing faults under oblique-slip conditions in the Penguin C Field created small-scale lozenge-shaped transpressional and transtensional fault blocks. The presence of reverse faults in the area is explained with a continuous kinematic model of structural evolution and oblique-slip fault reactivation rather than positive basin inversion.

Description: Geomechanical simulations are used to demonstrate the importance of the way that models are loaded. In this paper the development of permanent damage during faulting using frictional-slip models of a reverse fault is investigated. Although the use of different loads and constraints can produce the same faulted geometry (for the same rock type, and at the same burial depth), the models develop very different stress and strain states. Permanent strain magnitudes and distributions between models are quite dissimilar, including the distributions of permanent dilation and compaction. This work demonstrates that boundary loads and boundary constraints are significant factors in determining what stress and deformation states evolve in the simulation model. The examples also illustrate that final (deformed) geometry alone is a very poor basis from which to predict either stress state or open fracture distribution. Bulk finite strain does not allow a prediction of local principal stress directions, magnitudes, or signs, at least in the vicinity of fault damage zones.

Description: Traditionally, the analysis of fault seal has been purely deterministic or a combination of deterministic and stochastic methods. In a deterministic model, prediction of the locations of reservoir overlaps is made from the static model of the reservoir horizon and fault geometry. The principal aim is to map faulted reservoir overlaps and determine their sealing character. This is usually performed using a predictive algorithm such as the shale gouge ratio (SGR) that relates the shale content of the formations that have moved past a point on the fault zone to the sealing capacity of the fault rock. Deterministic fault seal studies are sensitive to the uncertainties associated with mapping of horizons in proximity to faults and the inherent uncertainty in a static fault interpretation in both position and fault zone complexity. Uncertainty in the static structure model can be addressed by convolving uncertainty in throw magnitude with juxtapositions at the fault. However, this does not address the uncertainty in the distribution of reservoirs on either side of the fault. With stochastic models multiple realizations of the stratigraphy can be tested. Stochastic models capture the uncertainty in the position of the reservoir at the fault by allowing multiple realizations of stacking geometries, where the principal assumption is that these stacked reservoir zones are laterally continuous covering the entire likely fill area. Despite the conceptual differences between these two approaches to fault seal analysis, comparison of the predictions they make on the Ling Gu field shows a surprising degree of conformity. The cut-off used to determine the number of sand and shale beds in the stochastic workflow appears to account for seal by fault zone materials, since a conservative cut-off implies fewer sand beds with lower probability of leak and correlates with more shale in the section and higher SGR values.

Description: Reservoir compartmentalization is one of the key issues that affects the development and production phase of gas fields. To improve prediction of the effects of compartmentalization on production, a new method has been developed to allow petroleum engineers to incorporate geologically-reasonable fault rock flow properties into upscaled dynamic reservoir simulation models. The first stage of the workflow is to estimate the permeability and capillary characteristics of fault rocks within the field. These data are then combined with estimates of fault rock thickness, derived from outcrop studies, to calculate transmissibility multipliers to take into account the impact of faults on fluid flow within the dynamic model. Our method differs from most others in that we have attempted to account for the two-phase flow properties of fault rocks in the dynamic models from producing reservoirs. Application of the model to real field examples provides far faster history matching than has been achieved previously. In addition, taking into account the multi-phase flow properties of fault rocks explains production behaviour that previous models could not. Although, the focus of this study has been on the Southern Permian Basin in the North Sea, the same approach could be applied to other areas.

Description: This paper describes basic rules-of-thumb' that offer an indication of common uncertainties and pitfalls, as well as the analytical methods, data requirements and work elements required to replicate the impact of faults on fluid flow in production simulation models successfully. The first, and most important, stage in this modelling process is to ensure that an accurate structural interpretation is incorporated into the simulation model. In particular, that all fault linkages and cross-fault juxtapositions are taken from the seismic interpretation into the simulation grid. Fault rocks sometimes reduce the rate of cross-fault flow in which case it is important to account for this reduction in flow within simulation models. This is best achieved if databases of fault rock properties, measured from the field of interest or nearby similar reservoirs, are up-scaled to calculate fault transmissibility multipliers. It is sometimes necessary to consider not just the single-phase permeability but also the capillary pressure and relative permeability characteristics of the fault rocks present. Finally, all the relevant static and dynamic data must be appraised critically. However, the interpretation of such data is usually non-unique and misinterpretations can create errors in the production-related fault seal analysis. Where these basic guidelines are followed, it has been our experience that the project time required to achieve a history match of production data is dramatically reduced. In addition, as the history match is more geologically reasonable, the model is often more reliable for predicting the long-term behaviour of the reservoir. This gives confidence in the model's forecast to guide development planning and day-to-day field management decisions.

Description: Major faults are surrounded by damage zones of minor faults that, in siliclastic rocks, can form barriers to flow in their own right. Reservoir flow simulation, now a routine part of reservoir management, requires equivalent hydraulic parameters on the scale of the whole fault. Geological models of structurally complex reservoirs, from which flow simulator grids are generated, require information on the 3D characteristics of fault populations. Here, 3D stochastic models of fault damage zone (FDZ) architecture are generated based on fault population statistics (offset, orientation, length, thickness, spatial distribution) measured from seismic, outcrop and core data. These FDZ models provide input to a 3D discrete fault flow model (DFFM) and we consider the case when the minor faults have permeabilities (isotropic) that are several orders of magnitude lower than the host rock, and thus form partial barriers to flow. The DFFM is used to determine and characterize the impact of the parameters defining the FDZ on the predicted bulk FDZ permeability, connectivity, efficiency' as a barrier or retarder to flow, and the effective' fault rock throw to thickness relationship for the FDZ. The latter of the summary results presented provides a means for incorporating FDZs into conventional production simulation package models of structurally complex reservoirs.

Description: Twenty years have passed since Menzies & Hawkesworth extended the concept of metasomatism to mantle processes. The aim of this book is to gather together progress made on this topic since then. Most of the 14 papers reported in the volume rely on in situ major and trace element analyses of minerals and glasses in mantle xenoliths, and deal with different kinds of metasomatic agents at variable fluid/rock ratios in tectonic settings as different as intra-plate, mid-ocean ridge (ophiolites) and supra-subduction. The book contributes to the wide debate on the nature of the fluids migrating into the mantle wedge, as well as on the different residential times of the subduction signature. In addition papers on intra-plate settings deal with the problem of relating various metasomatic signatures to one single metasomatic event through an infiltration-reaction process.

Description: The South Atlantic Ocean evolved after rupture of the Sao FranciscoCongoRio de la PlataKalahari cratonic landmass and the Late Proterozoic fold belts. Break-up in the South Atlantic realm developed diachronously: rifting started in the south (Argentina) during the Jurassic and progressed towards the equatorial segment. The central portion was controlled by a rift-resistant cratonic nucleus (the Sao FranciscoCongo craton) and as a result underwent development of narrow basins; parts controlled by Neoproterozoic fold belts developed wide basins. The final break-up of western Gondwana and the onset of plate divergence were marked by thick wedges of seaward-dipping reflectors, located near the incipient ocean-ridge spreading centre that had already been formed by the time Aptian evaporites were deposited. Subsequently, a few episodes of intraplate tectonic and magmatic activity affected the Santos, Campos and Espirito Santo basins. Post-break up development of the offshore basins was affected by gravity gliding over the Aptian evaporites. Continental uplift may be invoked as the main cause of salt mobilization, generating prograding clastic wedges that thickened basin-wards and produced a loading effect on the salt basin. Coupled with onshore erosional unloading and the effects of the gravity gliding, this probably resulted in further flexural uplift of the continental margin.

Description: Two domains have previously been recognized in the Archaean Reguibat shield of NW Mauritania, based primarily on their gross lithological differences. New fieldwork has identified a major ductile shear zone (Tacarat-Inemmaudene Shear Zone) separating these domains and new geochronological studies show that the two domains record different Mesoarchaean histories. As such, the two domains are redefined as the Choum-Rag el Abiod Terrane and Tasiast-Tijirit Terrane. Previous isotopic studies of metamorphic lithologies of the eastern Choum-Rag el Abiod Terrane indicate a succession of crustal growth from about 3.5-3.45 Ga to between about 3.2 and 2.99 Ga. Isotopic data presented in this contribution from the Tasiast-Tijirit Terrane indicate that emplacement of major calc-alkaline plutons occurred at c. 2.93 Ga after volcanism (preserved as greenstone belts) that included late felsic eruptive centres dated at c. 2965 Ma. This Mesoarchaean intrusive and extrusive magmatism was confined to the Tasiast-Tijirit Terrane, where it was emplaced through migmatitic orthogneisses that are the oldest lithodemic unit of the Tasiast-Tijirit Terrane. Widespread bimodal, post-tectonic magmatism in both terranes included major granitic magmatism dated at c. 2730 Ma. The north-south- to NNE-SSW-trending curvilinear Tacarat-Inemmaudene Shear Zone that separates the two terranes records late intense transpressive ductile shearing. It has a flower structure over a horizontal distance of about 70 km across its southern portion with unquantifiable sinistral horizontal offset, and east-directed thrusting on its eastern side where it cuts into the Choum-Rag el Abiod Terrane. A new U-Pb zircon age of 2954{+/-}111 Ma is presented for a deformed granite confined within the central part of this shear zone. A minimum age for the shearing is provided by a previously determined c. 2.73 Ga age for a post-tectonic granite that cuts across the easternmost part of the shear zone in the Choum-Rag el Abiod Terrane.

Description: The Guelb Moghrein Fe oxide-Cu-Au-Co deposit is located at the western boundary of the West African craton in NW Mauritania. The wall rocks to the mineralization represent a meta-volcanosedimentary succession typical of Archaean greenstone belts. Two types of meta-volcanic rocks are distinguished: (1) volcanoclastic rocks of rhyodacite-dacite composition (Sainte Barbe volcanic unit), which form the stratigraphic base; (2) tholeiitic andesites-basalts (Akjoujt meta-basalt unit). The trace element signature of both types is characteristic of a volcanic arc setting. A small meta-pelitic division belongs to the Sainte Barbe volcanic unit. A meta-carbonate body, which contains the mineralization, forms a tectonic lens in the Akjoujt meta-basalt unit. It can be defined by the high XMg (=36) of Fe-Mg carbonate, the REE pattern and the {delta}13C values of -18 to -17{per thousand} as a marine precipitate similar to Archaean banded iron formation (BIF). Additionally, small slices of Fe-Mg clinoamphibole-chlorite schist in the meta-carbonate show characteristics of marine shale. This assemblage, therefore, does not represent an alteration product, but represents an iron formation unit deposited on a continental shelf, which probably belongs to the Lembeitih Formation. The hydrothermal mineralization at 2492 Ma was contemporaneous with regional D2 thrusting of the Sainte Barbe volcanic unit and imbrications of the meta-carbonate in the upper greenschist facies. This resulted in the formation of an ore breccia in the meta-carbonate, which is enriched in Fe, Ni, Co, Cu, Bi, Mo, As and Au. Massive sulphide ore breccia contains up to 20 wt% Cu. The ore fluid was aqueous-carbonic in nature and either changed its composition from a Mg-rich oxidizing to an Fe-rich reducing fluid or the two fluid types mixed at the trap site. All lithologies at Guelb Moghrein were deformed by D3 thrusting to the east in the lower greenschist facies. The mobility of REE in the retrogressed rocks explains the formation of a second generation of hydrothermal monazite, which was dated at c. 1742 Ma. Archaean rocks of the West African craton extend to the west to Guelb Moghrein. The active continental margin was deformed and mineralized in the Late Archaean-Early Proterozoic and again reactivated in the Mid-Proterozoic and Westphalian, showing that the western boundary of the craton was reactivated several times.

Description: The Siroua massif includes many plutons of Neoproterozoic age. The mineralogical and geochemical character of the plutons allows us to describe an evolution of the magmatism, in space and time, from a subduction-related type in the northern part, to a within-plate subalkaline type in the southern part. The first magmatic activity coeval with the closing of the Khzama oceanic basin in the north is little evolved and of oceanic type (dominantly gabbros and basalts). It is followed by a low potassic calc-alkaline magmatism (gabbro-diorites, tonalites and trondhjemites of Nebdas pluton) and by a voluminous highly potassic calcalkaline magmatism (Askaoun and Ifouachguel plutons) that marks the collisional period. The end of crustal uplift and the beginning of the extension is marked in the south by a sub-alkaline magmatism corresponding to the Ida ou Illoun, Imdghar and Affela N'ouassif granites. Magmatic activity, in the Siroua massif, is marked at the end of the Neoproterozoic (PIII) by a continental tholeiite with an alkaline affinity, which occurs as dykes crosscutting the Neoproterozoic granites, and later by dominantly alkaline granites.

Description: A new halecomorph fish is described from the Early Cretaceous Marizal Formation of Tucano Basin. This new material is identified as a new species of Placidichthys, P. tucanensis sp. nov. based on the absence of an anal fin, the lower number of flank scales in the caudal region, the slender shape of the body, and body proportions. Placidichthys tucanensis sp. nov. increases the distribution and diversity of ophiopsids in the western part of the Tethys Sea, being distributed along the epicontinental seas of Gondwana. Placidichthys is considered the sister-taxon of the exclusively Cretaceous taxa Teoichthys+Macrepistius from the western Tethys. These groups show a discernible geographical distribution pattern with Placidichthys known only from the Southern margin of the Tethys region (South America), whilst Teoichthys and Macrepistius are known only from North America and possibly Europe.

Description: The Osteoglossomorpha are a clade of primitive teleostean fishes with modern representatives in five biogeogeographic regions and fossil representatives on six continents. The centre of modern diversity is in Africa but the centre of fossil diversity is in E Asia. Key fossil taxa include: {dagger}Phareodus, {dagger}Joffrichthys, and {dagger}Ostariostoma in N America; {dagger}Lycoptera, {dagger}Paralycoptera, and {dagger}Huashia among others in E Asia; {dagger}Brychaetus and possibly {dagger}Thaumaturus in Europe; {dagger}Palaeonotopterus, {dagger}Singida, and {dagger}Chauliopareion in Africa; {dagger}Tavernichthys in India; and {dagger}Musperia in SE Asia. Morphological phylogenies to date have disagreed on three main points: the relationships of {dagger}Lycoptera, of Pantodon, and of Notopterids and Mormyrids. Molecular phylogenies have similarly differed on the last two points. In this study a combined set of morphological data was generated from previous studies, including data from three recently described or redescribed taxa (the African {dagger}Singida and {dagger}Chauliopareion and the Chinese {dagger}Xixiaichthys) and maximum parsimony was used to generate a revised hypothesis of relationships. Our analysis recovered {dagger}Lycoptera, {dagger}Paralycoptera+ {dagger}Tanolepis, and {dagger}Xixiaichthys as stem-group osteoglossomorphs, {dagger}Singida as sister to Pantodon within Osteoglossidae, {dagger}Chauliopareion as a stem osteoglossid, {dagger}Ostariostoma as a stem osteoglossiform, and Notopteridae as sister to Mormyroidea and {dagger}Palaeonotopterus. These results do not lend themselves to easy explanations of osteoglossomorph biogeography involving either dispersal from a centre of origin or vicariant division of a widely distributed ancestor. Recent suggestions of an ancient (Palaeozoic) origin for osteoglossomorphs are flawed. The evidence, instead, is consistent with an origin within the Mesozoic and the biogeographic explanation involves extensive extinction of clades from continents where they occurred in the past.

Description: Fossil cypriniforms are abundantly represented in China and its adjacent areas, with the described taxa approximating to a total of 80 genera and 100 species and subspecies. They are known mainly from the Eocene, Miocene and Pliocene deposits. The Oligocene and Quaternary materials are relatively rare. These fossil cypriniforms represent three of the five Recent families: the Catostomidae, Cobitidae and Cyprinidae. Comparison of the Eocene catostomids from mainland East Asia with those from western North America points to an obvious transpacific distributional pattern, whereas there is only one species in Asia and more than 70 species in North America at present. Fossil cobitids are comparatively rare. Cyprinids are the most diverse and widespread group among the three families. The Miocene and Pliocene taxa shared by east mainland Asia and the Japanese Islands indicate that the fishes from these areas must have belonged to the same ichthyofauna during the Neogene. At the same time, some of them are quite similar to those from Europe, which is indicative of a closer connection between the two areas than previously thought.

Description: Since the discovery of ophiolite sequences, the Bou-Azzer inlier has been considered a key area for understanding the evolution of the northern margin of the West African craton during the Pan-African orogeny. For about 20 years, it had been commonly accepted that the Bou-Azzer inlier represents an accretionary melange accreted onto the West African craton under blueschist metamorphic conditions, similar to the Franciscan Complex and the Sanbagawa facies series. This would imply that a low geothermal gradient was prevalent during the subduction of the Pan-African oceanic plate, and that the ocean was subducted with a high convergence rate. A reinvestigation of the metamorphic conditions by a thermodynamic approach shows that the ophiolite sequence of Bou-Azzer underwent HT greenschist metamorphic conditions instead of blueschist metamorphic conditions. We propose that the ophiolites of Bou-Azzer are not similar to the Sanbagawa facies series or to the Franciscan Complex, but bear similarities to the Albanian or Cyprus ophiolites, which represent dismembered ophiolite sequences overprinted by greenschist conditions.

Description: The Anti-Atlas belt belongs to the northern fringe of the West African craton, moderately deformed during the Variscan orogeny south of the Meseta Block. Field-based investigations into the stratigraphy and structure of the Palaeozoic cover have been performed in the eastern part of Anti-Atlas, with emphasis on the Devonian terranes. The Pan-African basement, which crops out in the Ougnat massif, was fragmented into a mosaic of tilted blocks during a sequence of extensional faulting events that occurred from Cambrian to (mostly) Late Devonian times. The Devonian normal fault pattern indicates a multi-directional extension, with a dominant northward direction. The Variscan compression resulted in the inversion of the palaeofaults as strike-slip-reverse faults, the kinematics of which points to a NE-trending regional direction of shortening, probably Permian in age. The occurrence of the Late Devonian palaeofault array accounts for the thick-skinned style of the (eastern) Anti-Atlas belt. The Devonian paleogeography of the Anti-Atlas can be correlated with that of the Meseta, but the lack of any Late Devonian compressional event in the Anti-Atlas shows that the two domains were not mechanically coupled at that time.

Description: The crystalline basement of the Tauern Window is locally covered by Palaeozoic to Mesozoic sediments that experienced Alpine tectonometamorphism. The sedimentary cover has been subdivided into mappable lithological units. The correlation of these units, the use of some dated marker intervals and independent palinspastic restoration provide evidence that the depositional area was differentiated into basins and swells. At the end of the Variscan orogeny, during the Carboniferous and Permian, intermontane basins formed in basement rocks and mainly continental clastics accumulated in elongate troughs. Later, probably during the Triassic, there was levelling of the previous relief and subsidence of the basins, but continental sedimentation still prevailed although interrupted by some marine transgressions. Thereafter, probably during the Jurassic, the area was progressively flooded and the sedimentation became increasingly calcareous. The Upper Jurassic carbonates document complete submergence. In some areas, the Upper Jurassic carbonates directly rest on crystalline basement indicating renewed tectonic stretching. The sedimentary cover shows striking similarities with coeval deposits within the Germanic Basin and the study area is therefore considered to have been part of the southern European continental margin of the Tethys (the so-called Vindelician Land).

Description: Lower Permian volcanic and sedimentary rocks of the Collio Formation in the Orobic Anticline do not rest with a depositional contact on the Variscan basement but are separated from it by the subhorizontal Grassi Detachment Fault, consisting of a cataclasite layer underlain by mylonite. Field relations indicate that both the cataclasite and the mylonite are Early Permian in age. The mylonite formed in a continuous process before, during, and after the intrusion of the Val Biandino Quartz Diorite in the footwall of the detachment fault. Microstructure and quartz texture of the mylonite indicate top-to-the-southeast displacement. Quartz textures of mylonite close to the intrusive bodies are characterized by c-axis single maxima near the Y-direction of the finite strain, indicating prism 〈a〉glide as the dominant gliding system and hence high temperatures (above c. 500 {degrees}C) during mylonitization. This is explained by heat advection through the rising quartz diorite melt. During detachment faulting, the footwall of the Grassi Detachment Fault was bowed up to form a metamorphic core complex. The Ponteranica Conglomerate was deposited as a proximal, syntectonic fan-delta on the southeast side of the metamorphic core complex late in its evolution. The unconformity of the Verrucano Lombardo over the Collio Formation and the basement results from erosion of the topography created by detachment faulting, core complex updoming, and block tilting. These results indicate dramatic SE-NW stretching (in present-day coordinates) of the South-Alpine crust during the Early Permian. The return from the thickened, orogenic crust at the end of the Hercynian orogeny to the normal crustal thickness (c. 30 km) of Late Permian and Early Triassic times was accommodated to a large extent by crustal extension, at least in this part of the southern Alps.

Description: During Europe-Adria collision in Tertiary times, the Monte Rosa nappe was penetratively deformed in several stages after an eclogite-facies pressure peak: (1) top-to-the-NW thrust shearing (Mattmark phase, after 40 Ma); (2) orogen-parallel, top-to-the-SW extensional shearing and folding (Malfatta phase); (3) orogen-perpendicular, top-to-the-SE extensional shearing and folding (Mischabel phase, before 30 Ma); and (4) large-scale, upright, SE-vergent folding (Vanzone phase, c. 29-28 Ma). Structural analysis and neutron texture goniometry of quartz mylonites show that the Stellihorn shear zone in the Monte Rosa nappe accommodated a complex and multidirectional sequence of shearing movements during the Mattmark, Malfatta and Mischabel phases, and was folded in the Vanzone phase. In the tail-shaped eastward prolongation of the Monte Rosa nappe in the Southern Steep Belt of the Alps, both dextral and sinistral mylonites (Olino phase) were formed during and after the formation of the Vanzone fold, reflecting renewed orogen-parallel (SW-NE) extension contemporaneous with NW-SE shortening from c. 29 Ma onward. A similar sequence of deformation stages was identified in the Adula nappe at the eastern border of the Lepontine metamorphic dome. Important consequences arise for the Insubric fault at the southern border of the Lepontine dome: (1) the NW- to N-dipping orientation of the Insubric fault is not a primary feature but resulted from rotation of an originally SE-dipping shear zone after c. 30 Ma; and (2), the strong contrast in metamorphic grade across this fault (upper amphibolite facies to the north versus anchizone to the south) results from north-side-up faulting coupled with orogen-parallel extension of the northern block (Lepontine dome), while no such extension occurred in the southern block (Southern Alps). Extension in the northern block started in the Malfatta phase and continued in the Mischabel phase when the foliation in the area which later became the Southern Steep Belt still dipped towards south. During Vanzone/Olino deformation, further unroofing and uplift of the Lepontine dome relative to the South Alpine block took place while the Southern Steep Belt was progressively rotated into its present, overturned position, changing its character from a normal fault into a backthrust. Complex deformation paths in the Southern Steep Belt resulted from the combination of extension of the northern block with strike-slip motion along the Insubric fault.

Description: Flysch deposits are associated with the Outer Dinaride nappe front. They overlie Eocene platform carbonate to bathyal marl successions that subsequently cover Cretaceous platform carbonates of Apulia and the Dinaride nappes. Planktonic foraminifer biostratigraphy indicates Eocene age of flysch sedimentation. New calcareous nannofossil data reveal that several assemblages are present; besides the dominant Mid-Eocene species, Cretaceous, Paleocene, Oligocene and Miocene taxa were also identified throughout the entire flysch belt. Widespread occurrence of nannofossil species of zone NN4-6 indicates that flysch deposition lasted up to at least the Mid-Miocene. Ubiquitous occurrence of various pre-Miocene taxa demonstrates that extensive, possibly submarine, sediment recycling has occurred in the Cenozoic. As flysch remnants are typically sandwiched between thrust sheets, these new stratigraphic ages give a lower bracket on deformation age of the coastal range. The data provide a link between Cretaceous compression in the Bosnian Flysch and recent deformation in the Adriatic offshore area.

Description: The juxtaposition of the ALCAPA and Tisza-Dacia continental blocks, although one of the key issues in the evolution of the Carpathians, is not well known in terms of associated effects on the sedimentary systems during frontal foreland development. Most of the contact between ALCAPA and Tisza-Dacia being covered by post-tectonic deposits, these effects can best be observed in northern Romania. Sedimentological data on facies, palaeocurrents and modal composition of sandstones combined with micropalaeontological data and 2D well-calibrated seismic lines constrain the tectonic history of the contact zone between ALCAPA and Tisza-Dacia. Pervasive deposition of sand-dominated siliciclastics beginning in late Early Oligocene (Late Rupelian) times is interpreted to reflect the onset of convergence between ALCAPA and Tisza-Dacia in the study area. The depocentre of coarse siliciclastic material migrates southward, finally forming a southeastward-thinning clastic wedge in the Transylvanian Basin. This Burdigalian-age clastic wedge is interpreted as fill of a flexural foreland basin that formed in response to the coeval thrusting of parts of ALCAPA (Pienides) over Tisza-Dacia. A shift from an E-W to SE-NW striking basin axis during Oligocene times towards a WSW-ENE oriented basin axis during Burdigalian times is interpreted as a result of clockwise rotation of Tisza-Dacia during basin formation.

Description: Our study aims to characterize the post-glacial neotectonic activity by finding surface expressions of recently active tectonic faults. The central and western Swiss Alps were chosen as the study area because surface uplift rates are very high, indicating ongoing uplift of the external basement massifs. Moreover, the Valais area coincides with enhanced seismic activity. Active faults were searched by mapping lineaments on aerial photographs and subsequent field studies. Three main types of faults could be distinguished: gravitational faults (i.e. faults related to mass movements); tectonic faults; and composite faults (i.e. tectonic faults with a component of gravitational and post-glacial rebound-related reactivation). A large number of tectonic faults were found (over 1700), but only two unequivocally post-glacially active tectonic faults could be distinguished. Indications for their post-glacial (re-)activation are displaced Quaternary landforms or sediments. Large gravitational faults, as well as composite faults often correlate with deep-seated gravitational slope deformations (DSGSD). The latter occur mainly along valley slopes, particularly where a pervasive foliation strikes parallel to the valley. Fault orientations show correlations either with the regional main foliation (e.g. Aar and Gotthard massif), the orientation of valleys (e.g. Bedretto and Urseren valley), or pre-existing tectonic structures (e.g. faults parallel to joints that are perpendicular to the strike of major structures in the Helvetic nappes). Comparisons of fault orientations with orientations of nodal planes of earthquake focal mechanisms of the last 20 years show a poor indicative correlation. The central and western Swiss Alps host a large number of faults prone for reactivation in today's stress field. However, for most of these faults, no indications of their last phase of activity exist. The low number of unambiguously active tectonic faults suggests that the current strain is either predominantly aseismic or, alternatively, cumulated seismic moment is too low for producing surface rupture.

Description: The geometry and evolution of normal fault terminations were studied in Tithonian limestones exposed on a vertical cliff in the French SE-Basin. The rocks consist of mainly limestone layers alternated with thin clayey interlayers. All studied fault zones die out vertically into bed-perpendicular veins striking approximately parallel to the fault. Displacement decreasing to zero towards the fault tip is accommodated horizontally by bed-parallel opening of calcite veins, and vertically by bed-perpendicular localized compaction. The latter mechanism leads the clayey interlayers to be thinned and in places completely pushed out, and enhances pressure solution in bed-parallel seams. The respective thicknesses of the limestone layers and clayey interlayers, and the ratio between local displacement amount and bed thickness influence the geometries of the fault termination and of the steps between slip surfaces. Relatively thick clayey interlayers localize low-angle slip surfaces and may impede the vertical propagation of the slip surface. Vertical fault restriction is also related to thick limestone layers, which are deflected and affected by outer arc extensional fractures, localized pressure solution and dilational jogs connecting adjacent propagating slip surfaces. However, beds keep their continuity if thicker than the local displacement amount. Where the local displacement is larger than the layer thickness, limestone beds are disconnected and clayey interlayers are completely cut but the slip surfaces. Tip-point veins, as well as outer arc veins, do not cross the clayey interlayers and fluid flow is local and confined within one limestone layer. In contrast, dilational jogs in places cut through several layers, and the breaking of clayey interlayers causes an increase in fluid flow. Conduits can be opened along the fault zone and fluids are driven into the jog, so slip surfaces may communicate separate reservoirs, until dilational jogs are sealed by mineral precipitation.

Description: This study is concerned with a newly recognized structure at the southwestern border of the Tauern Window and the neighbouring Austroalpine basement rocks, the Lappach Structure. Structural and isotopic investigations show that this structure is the result of sinistral transpression and backthrusting along the Austroalpine-Penninic contact. Deformation partitioning and differential exhumation of crustal wedges is documented by a succession of ductile and brittle deformation stages. Two stages are distinguished: (1) up-doming of Penninic units and associated advective heat transfer caused a strong temperature variation with the highest temperatures in central portions of the Tauern Window. Coeval transpression with distributed sinistral shear formed high-temperature, partly annealed fabrics in central portions and lower-temperature fabrics with strong crystallographic preferred orientation of quartz along the Tauern Window margin. Southward decrease of temperatures was matched by increases in stress and deformation intensity. (2) Progressive cooling was accompanied by shear localization, deformation partitioning and fluid infiltration. Overall sinistral shear resolved in a discrete strike slip-fault and south vergent folds with associated thrusts defining a backthrust zone along the southern Tauern margin. Southwards extrusion disturbed previously established palaeo-isogrades and juxtaposed rocks from greater depths against lower-grade metamorphic units. Fluids penetrated faults, reduced shear strength and contributed to shear localization.

Description: The fluid flow properties of faults are highly variable and spatially heterogeneous. We use numerical simulation of flow through field maps of detailed fault zone architecture to demonstrate that flow across the fault zone is controlled by connected high-permeability pathways, which are highly tortuous in mapped fault outcrops. Such small-scale, geometrically complex, fault zone architectural features can never be resolved for subsurface faults. Consequently, the key to prediction of subsurface bulk fault zone hydraulic properties is a statistical characterisation of the likelihood and frequency of such connected pathways. We demonstrate for a single architectural feature, the fault core, that thickness variation along strike can be well described by a spatially correlated random field with a spherical covariance structure. These data are from a single site in a specific lithology. To enable such statistics to be used to make predictions at other sites, a large number of similar datasets must be pooled. This will enable us to relate such spatial statistics to gross properties such as host rock lithology and fault throw, which are measurable for subsurface faults.

Description: The influx of fluids into fault zones can trigger two main types of weakening process that operate over different timescales and facilitate fault movement and earthquake nucleation. Short- and long-term weakening mechanisms along faults require a continuous fluid supply near the base of the brittle crust, a condition satisfied in the extended/extending area of the Northern Apennines of Italy. Here carbon mass balance calculations, coupling aquifer geochemistry to isotopic and hydrological data, define the presence of a large flux (c. 12 160 t/day) of deep-seated CO2 centred in the extended sector of the area. In the currently active extending area, CO2 fluid overpressures at [~]85% of the lithostatic load have been documented in two deep (4-5 km) boreholes. In the long-term, field studies on an exhumed regional low-angle normal fault show that, during the entire fault history, fluids reacted with fine-grained cataclasites in the fault core to produce aggregates of weak, phyllosilicate-rich fault rocks that deform by fluid assisted frictional-viscous creep at sub-Byerlee friction values ({micro}〈0.3). In the short term, fluids can be stored in structural traps, such as beneath mature faults, and stratigraphical traps such as Triassic evaporites. Both examples preserve evidence for multiple episodes of hydrofracturing induced by short-term cycles of fluid pressure build-up and release. Geochemical data on the regional-scale CO2 degassing process can therefore be related to field observations on fluid rock interactions to provide new insights into the deformation processes responsible for active seismicity in the Northern Apennines.

Description: This paper highlights the use of synkinematic white mica, biotite and phlogopite for the dating of deformation in ductile shear zones within crystalline rocks under low-grade metamorphic conditions. The Mont Blanc shear zones range from 1 mm to 50 m in width and have localized intense fluid flow, resulting in substantial differences in mineralogy and whole-rock geochemistry. On the basis of their synkinematic alteration assemblages and geographic distribution within the Mont Blanc Massif, three main metamorphic zones are distinguished within the network of shear zones. These are: (i) epidote{+/-}white mica-bearing assemblages; (ii) chlorite-phlogopite-bearing assemblages; and (iii) white mica{+/-}biotite{+/-}calcite{+/-}actinolite{+/-}epidote- bearing assemblages. 40Ar/39Ar age spectra of biotite and phlogopite are complex, and reflect significant variations in chemical composition. In biotite, this is partly due to inheritance from precursor Variscan magmatic biotite. In contrast, new white mica grew at the expense of feldspar during Alpine deformation and its Ar spectra do not show any excess 40Ar. On the SE side of Mont Blanc, ages of shear zone phengites have a narrow range of 15.8-16.0{+/-}0.2 Ma, which is in the same age range as 40Ar/39Ar ages of minerals from kinematically related veins. The top-to-SE sense of shear is consistent with initiation of a Mont Blanc flower-structure within a dextral transpressional system by 16 Ma. On the NW side, mini-plateaux ages of 14.5{+/-}0.3 and 23.4{+/-}0.4 Ma are preserved in the same sample, suggesting the possibility of two phases of deformation. This is also supported by partly preserved ages of 18-36.6 Ma in biotites and phlogopites. Ages between 36 and 18 Ma might reflect ongoing top-to-NW thrusting, following Penninic Front activation, in a context of nappe stacking and crustal thickening. NW-directed thrusting on the NW side of Mont Blanc continued after 18 Ma, synchronous with SE-directed thrusting on the SE side of the massif. These divergent movements produced the overall pop-up geometry of the Mont Blanc Massif, which may correspond to a positive flower structure developed within a zone of regional dextral transpression extending SW from the Rhone valley into the Mont Blanc area.

Description: Detailed mapping of complex fault zones shows that secondary faults often branch off the principal slip zone. However, the effect of secondary branch faults on the hydrodynamic behaviour of fault zones has not yet been examined, largely because of a lack of hydraulic data and because numerical or analogue modelling of splay faulting is a complex issue. This contribution investigates the thermal pressurization process in cases of slip along a principal slip zone and along splay faults branching off the principal displacement zone. The study is based on porosity and permeability data presented in this paper from the principal and secondary slip zones of an active, clay-rich gouge-bearing strike-slip fault, the Usukidani fault of SW Japan. Modelling constrained by these data suggests that thermal pressurization is a viable process only as long as the rupture remains located in the central gouge zones or in mature splay fault gouge zones. Splaying of the rupture into surrounding microbreccias or into immature or newly generated splay faults of higher permeability will release fluid pressure or inhibit the generation of coseismic excess fluid pressures by thermal pressurization. The modelling results suggest that secondary fault branches can play a key role in controlling fluid pressurization during faulting. Hence, complete investigation of active fault zones needs to include secondary faults and their corresponding hydraulic behaviour, in order to establish the influence of such structures on earthquake mechanics.

Description: Tokyo is situated in the southern part of the Kanto Plain, the largest plain in Japan. It is filled with thick marine Quaternary sediments deposited in the Palaeo-Tokyo Bay. The concept of a Palaeo-Tokyo Bay was proposed by Hisakatsu Yabe in 1913 and 1914, based on molluscan fossils, geography and tectonics. Palaeo-Tokyo Bay used to open to the east and, at the time of the high sea-level phase, perhaps also to the south, whereas the modern Tokyo Bay opens to the south. The Paleao-Tokyo Bay concept is supported by recent sedimentological evidence, sequence stratigraphy and tectonic studies, and is considered to have formed in a forearc basin near the triple junction of plates (the Pacific, Asian and Philippine plates) and trenches (Japan Trench, Sagami Trough and Izu-Ogasawara Trench) in the Quaternary. The bay is unique and shows evidence of repeated differential vertical movements during its formation.

Description: Thomas Griffith Taylor was one of Australia's leading geoscientists in the early twentieth century. He also developed ideas on race and environment at Sydney University, supposing that brachycephalic people had greater intellectual capacity than dolichocephalics, so that Chinese settlement in Australia was desirable. In consequence, Taylor's promotion at Sydney University was blocked. He therefore moved to a chair at Chicago, and thence to Toronto. He retired to Sydney in 1951 and in his old age published a classic study of the landforms of the region: Sydneyside Scenery (1958, published by Angus & Robertson, Sydney). This little book, although scientifically somewhat dated even at the time of its publication, summarized Taylor's earlier geomorphological ideas about Sydney and its hinterland. It applied Davisian ideas to the Sydney region, harking back to the work that Taylor and others had done in the early twentieth century. Taylor's ideas about the Sydney region's river patterns are described and their relationship to supposed Earth movements. In particular, Davisian ideas about river capture and antecedent drainage, and the topography of the Blue Mountains, are discussed in relation to the empirical information and theoretical ideas available in the early twentieth century. Taylor's ideas, as described in 1958, seem(ed) plausible, but they were subsequently thrown in doubt or invalidated by consideration of the form of diatremes in the Blue Mountains, by new geological theory, new data about the ages of rocks and minerals and estimates of the timing of Earth movements, closer mapping of structures, etc. The case exemplifies both the explanatory power, and the weaknesses, of Davisian geomorphology. E.C. Andrews preceded Taylor in introducing American geomorphological ideas into Australia and propounded the idea of Late Tertiary-Pleistocene uplift in eastern Australia, which was held responsible for many of the features that Taylor described. Other important contributors were W. G. Woolnough (1876-1958) and T. W. E. David (1858-1934), who taught Woolnough, Andrews and Taylor. A consensual view of the geomorphological and tectonic history of the Sydney region has still not been achieved.

Description: This contribution summarizes the considerations that are of major importance in inorganic mineral formation before we look at specific biological minerals. Some factors which have to be taken into account (other than those that are well-known from inorganic (abiological) precipitations) are: the nature of the biological organic matrix; the restricted volume, outside or inside the cytoplasm, which can cause differences in impurity content (Mg); crystal morphology; and isotopic fractionation. Cases such as those of corals, foraminifera and coccoliths are taken as examples.

Description: The geology of Warwickshire, central England, is diverse but generally poorly exposed. Geological conservation initiatives can be traced back to the mid to late nineteenth century when the Warwickshire Natural History and Archaeological Society amassed locally collected geological specimens and documented local geological sites. The society declined during the late nineteenth century. Following the Second World War, local geological conservation activity was invigorated by national initiatives, leading to establishment of geological Sites of Special Scientific Interest within the county and a site recording programme at the Warwickshire Museum. The Warwickshire Geological Conservation Group was established in 1990. Subsequently, a partnership between that group and the Warwickshire Museum, with support from the Nature Conservancy Council, resulted in establishment of a Regionally Important Geological/geomorphological Sites network. These sites are presently the focus of funded conservation and interpretation projects.

Description: Individual faults, faults linking at depth in flower structure zones and jogs bounded by faults are common structural elements in strike-slip fault systems and can play an important role in controlling thermal fluid flows. This paper explores the influence of these structures on the thermal circulations and fluid outflows of Terme di Valdieri, in the crystalline basement of the Argentera Massif (western Alps). In this site, thermal waters upwell at the tip of a NW-trending right-lateral fault, but exactly which structures control infiltration of meteoric waters and deep circulation is not clear from field surveys. Three-dimensional thermohydraulic numerical models calculated in steady-state and in transient regimes are presented for three alternative hypotheses. These account for circulations occurring: (i) within a single fault and adjoining host rocks; (ii) in faults intersecting at depth; and (iii) in faults interacting by means of a permeable step-over. The simulations show that advective flows can coexist with convective flows in models (i) and (iii), provided that the fault permeabilities are higher than 2x10-13 m2, while advection prevails in model (ii) at all values of permeability. Model (iii) achieves the best fit to the data under the assumption of advective and convective flows. This finding provides a first quantitative estimate of the importance of jog structures bounded by strike-slip faults in favouring thermal outflows. Moreover, the numerical results suggest that thermal convection can coexist with advection also in mountainous settings.

Description: There are continual rounds of annual conferences, special sessions and other symposia that provide ample opportunity for researchers to convene and discuss igneous processes. However, the origins of laccoliths and sills continue to inspire and confound geologists. In one sense, this is surprising. After all, don't we know all we need to know about these rocks by now? As testified by the diverse range of topics covered in this volume, the answer is clearly no'. This book contains contributions on physical geology, igneous petrology, volcanology, structural geology, crustal mechanics and geophysics that cover the entire gambit of geological processes associated with the shallow emplacement of magma. High-level intrusions in sedimentary basins can also act as hydrocarbon reservoirs and as sources for thermal maturation. In drawing together a diversity of perspectives on the emplacement of sills, laccoliths and dykes we hope to advance further our understanding of their behaviour.

Description: Recent works have paved the way for an understanding of the scale at which environmental signals might be recorded in coral skeletons. In this paper, the resulting structural and chemical insights are exemplified by a Goniastrea corallite. The bulk of the coral skeleton consists of fibrous aragonite, which in turn is constructed by sequential growth of micrometre thick layers, oriented parallel to the local growth direction. These growth layers consist of nanograins (50-100 nm) of aragonite that appear to be crystallized in close association with a matrix, conceivably proteoglycans, which seem to coat individual nanograins. These observations contradict the traditional notion that coral fibre consists of a single crystal of orthorhombic aragonite'. Additionally, the ultrastructural observations provide us with criteria to assess early diagenetic effects. Some Lower Norian corals from South Anatolia (Turkey) display extremely well-preserved mineralogy and structures. They have also preserved the organic components of their skeletons from which it has been demonstrated, through a study of the Nitrogen isotopic composition, that photosynthesis was involved in the metabolism of these early Scleractinia. But even in these remarkably preserved corals, we find evidence for diagenetic changes at the nanometre scale, concerning both the amount of organic matrices and the appearance of the aragonitic nano-granular units. Such micro-structural observations call for caution when interpreting isotopic effects in the fossil coral record.

Description: Most fossil deep-sea foraminifera are multichambered and have relatively robust, calcareous or agglutinated shells. Modern assemblages, on the other hand, include many fragile monothalamous (single-chambered) forms and komokiaceans (a superfamily of protist currently placed within the foraminifera) with soft test walls. These groups are poorly known and most of the hundreds of morphospecies recognized in deep-sea samples are undescribed. The relative abundance of robust and fragile taxa varies with water depth and food supply. Calcareous and other hard-shelled species tend to predominate in relatively eutrophic areas, particularly on continental margins, but decrease as a proportion of the entire' live fauna (i.e. including soft-shelled species) with increasing water depth, even above the CCD (carbonate compensation depth). Most of the species on which the foraminiferal proxies used in palaeoceanography are based live in these bathyal regions. At abyssal depths, and particularly below the CCD, faunas are largely agglutinated and dominated by monothalamous forms. These assemblages have a much lower fossilization potential than those found on continental margins. In addition to carbonate dissolution, these patterns probably reflect adaptations to increasingly oligotrophic conditions on the ocean floor with increasing depth and distance from land. Bathyal species include herbivores and opportunistic deposit feeders (omnivores) that consume labile organic material, in addition to deep-infaunal deposit feeders, and must contribute significantly to carbon cycling. Many abyssal monothalamous foraminifera, in constrast, accumulate stercomata (waste pellets composed of fine sediment particles) and probably ingest sediment, associated bacteria and more refractory organic matter. Some monothalamous species without stercomata may be bacteriovores. Although they probably process organic carbon at a slower rate than calcareous species, the shear abundance of monothalamous taxa at abyssal depths suggests that they are important in carbon cycling on a global scale. The loss of a substantial proportion of foraminiferal biomass and biodiversity from the fossil record should be considered when using foraminifera to reconstruct palaeoproductivity, for example, by using the Benthic Foraminiferal Accummulation Rate (BFAR). Different dietary preferences among calcareous species have implications for the stable carbon isotope signal preserved in their shells.

Description: Recent findings are reviewed from observations in the field on the generation of the {delta}13C signal in shells of live (Rose Bengal stained) benthic foraminifera, and end up with implications for the interpretation of fossil signatures. The {delta}13C values of calcite tests of preferentially epifaunal foraminifera principally reflect the {delta}13C of dissolved inorganic carbon (DIC) of ambient seawater, whereas infaunal species record a porewater signal, both with an offset from equilibrium calcite. Species occupying the deepest average living depth in the sediment usually exhibit lowest {delta}13C test values, but {delta}13C values of conspecific specimens at a single site do not decrease with increasing subbottom depth and decreasing porewater {delta}13CDIC. Organic carbon fluxes to the sediment surface are generally reflected by infaunal species such that lowered {delta}13C values coincide with high fluxes, but even strictly epifaunal species may reflect seasonally pulsed phytodetritus supply by depleted test {delta}13C. In high-productivity environments, however, where dissolved oxygen and sedimentary carbonate contents are low, benthic foraminiferal tests show 13C enrichment probably due to carbonate-ion undersaturation. Ontogenetic increase in {delta}13C values of certain infaunal species suggests a slow-down of metabolic rates during test growth and decreasing fractionation with age. At sites of active methane discharge {delta}13C values of infaunal species reflect low pore water {delta}13CDIC values, documenting active methane release in the sediment, whereas lowered {delta}13C values of strictly epifaunal species are most probably the result of incorporation of 13C depleted methanotrophic biomass.

Description: Laboratory cultures of several species of benthic foraminifera were grown under controlled physical and chemical conditions during months-long experiments carried out at the University of South Carolina in 2001 and 2002. A dozen experimental culture chambers contained a c. 1-3 mm layer of trace-metal free silica substrate, and were continuously flushed with water from a large (1600 L) seawater reservoir with known, constant temperature and composition ({delta}18O(water), carbonate system chemistry, and trace element concentrations). Each year, in most of the culture chambers, one or more species reproduced, producing hundreds of juveniles which grew into size classes ranging from 100 to 500 microns. Bulimina aculeata was the most successful species in the 2001 cultures, and both B. aculeata and Rosalina vilardeboana were abundant in 2002. We determined the shell C and O isotopic composition of the cultured foraminifera, and compared these isotopic values with the water chemistry of the culture chambers, and also with the shell chemistry of field specimens collected from sites on the North Carolina and South Carolina (USA) continental margin. The cultured foraminifera showed substantial offsets from the {delta}13C of system water dissolved inorganic carbon (-0.5 to -2.5{per thousand}, depending on species) and smaller offsets (0 to -0.5{per thousand}) from the predicted {delta}18O of calcite in equilibrium with the culture system water at the growth temperature. These offsets reflect at least three factors: species-dependent vital effects; ontogenetic variations in shell chemistry; and the aqueous carbonate chemistry ([CO3-] or pH) of the experimental system.

Description: Pronounced seasonal heating of middle and high latitude shelf seas results in large temporal changes in seawater temperature that have the potential to be recorded by benthic foraminifera. Predicted oxygen isotope composition for calcite precipitating in equilibrium conditions with seawater suggest that pronounced seasonal isotope effects' may be encountered in the growth history of benthic foraminifera. Such seasonal' effects can be difficult to distinguish from so-called vital effects', where shell and equilibrium calcite values are offset by a constant difference in oxygen isotope values. Preliminary findings suggest that benthic foraminifera may have more than one phase of growth, for example Ammonia becarii calcifies in spring and late summer, potentially introducing apparent intra-annual and inter-annual temperature variations of 〉1{degrees}C into palaeoclimatic reconstructions when mixed-season populations are sampled. We highlight the need to select species-specific palaeotemperature equations to establish reliable isotopic disequilibria and illustrate the importance of understanding the seasonal isotope effect' when considering disequilibrium effects in foraminifera which have grown in seasonally-changing environments.

Description: A structural investigation of the Slieve Gullion ring-complex, part of the approximately 56 Ma Slieve Gullion Igneous Centre, County Armagh, Northern Ireland was carried out with a view to testing the ring-dyke emplacement mechanism. This investigation involved the detailed examination and mapping of critical field relationships and the measurement of visible and magnetic fabrics, within the porphyritic rhyolite (felsite) and the porphyritic granite (granophyre) parts of the ring-complex. Set against existing theories for the emplacement of this complex, our investigation failed to find steep outward-dipping fabrics and lineations that would support the emplacement of this ring-complex as a ring-dyke. Instead, we propose that the ring-complex was emplaced as a series of extrusive and intrusive subhorizontal sheets, controlled by a circular zone of deformation, and subsequently domed by the emplacement of the younger central complex. From its gently dipping bulk geometries and a disharmonically folded eutaxitic internal fabric (supported by AMS - anisotropy of magnetic susceptibilty), the earlier rhyolite is reinterpreted as a pyroclastic deposit. The rhyolite was probably deposited against the wall of a subsiding caldera and is now preserved in the SW quadrant of the complex. From primary intrusive contact geometries with pre-Palaeogene country rocks, magnetic fabrics and subtle visible foliations - all of which are gently dipping - the younger and more extensive granitic ring is suggested to have initially been a subhorizontal sheet that is now domed. Only its gently outward-dipping floor is exposed around the ring-complex, and this is for much of its circumference bounded by a circular zone of deformation - a ring-fault. This study highlights the importance of detailed structural investigation in assessing the emplacement of igneous ring-complexes, emphasizing the need to look further than a simple ring-dyke emplacement model.

Description: Experiments were performed to determine melt concentration and strain distributions around basalt dykes in a San Carlos olivine matrix containing 10 wt% MORB (mid-ocean ridge basalt). Undrained triaxial compression tests were conducted at 1473 K and a confining pressure of 300 MPa, at constant stresses (80-160 MPa) and constant strain rates ranging from 5x10-5 to 3x10-4 s-1. Melt distribution in the dyke-matrix interface was determined by image analysis and chemical profiles. Melt migration appears to be enhanced by porosity of the microstructure and by the loading conditions. The presence of the dyke does not influence the bulk strength of the sample. Highest melt concentrations, and, presumably, the highest stress concentrations, are found at the tip of the dyke. The matrix deformation appears to be controlled by granular flow, but dilatancy occurs near the tip of the dyke, indicating coupled MORB transport and granular flow.

Description: Magmas are subject to a series of processes that lead to their differentiation during transfer through, and storage within, the Earth's crust. The depths and mechanisms of differentiation, the crustal contribution to magma generation through wall-rock assimilation, the rates and timescales of magma generation, transfer and storage, and how these link to the thermal state of the crust are subject to vivid debate and controversy. This volume presents a collection of research articles that provide a balanced overview of the diverse approaches available to elucidate these topics, and includes both theoretical models and case studies. By integrating petrological, geochemical and geophysical approaches, it offers new insights to the subject of magmatic processes operating within the Earth's crust, and reveals important links between subsurface processes and volcanism.

Description: The Tertiary kinematic history of the Maramures area is constrained by integrating thermochronological (fission track and (U-Th)/He analysis) data with field-based structural investigations. This study focuses on the tectonic evolution of the northern rim of the Tisza-Dacia block during collision with the European margin. Cretaceous nappe stacking, related metamorphism as well as Late Cretaceous exhumation are evidenced by zircon fission track data. Subsequent Palaeogene to Early Miocene sedimentation led to burial heating and annealing of fission tracks in apatite. Final tectonic uplift was initiated during the convergence of Tisza-Dacia with the European margin, associated with transpressional deformation (16 to 12 Ma). This led to Mid-Miocene exhumation, recorded by apatite fission track cooling ages in the western part of the study area. Transtension between 12 and 10 Ma caused brittle deformation along E-W trending strike-slip faults and SW-NE trending normal faults, delimiting blocks that were tilted towards the SW. This fragmentation of the crust led to enhanced exhumation at rates of 1 mm/a in the central part of the study area, as is documented by Middle to Late Miocene cooling ages (13 to 7 Ma). The outside estimate for the total amount of exhumation since Middle Miocene times is 7 km.

Description: A variety of methods have been employed to decipher magmatic systems, including geophysical, petrological, textural and geochemical approaches, and these elucidate a large variety of characteristics of different plumbing systems and magmatic differentiation processes. A common theme to the papers presented in this book is the observation of transport of small volume magma batches with a relatively high frequency, as opposed to less frequent transport of larger magma volumes that would require storage in large crustal reservoirs for long periods of time. The implications of this observation are discussed in the context of a possible tectonic control on crustal magma dynamics.

Description: Most of our information about the evolution of Earth's ocean-climate system comes from the analysis of sediments laid down in the past. For example, the microfossil assemblage reflects the temperature, salinity and nutrient abundance of the water in which the organisms lived, while the chemical and isotopic composition of biogenic carbonates may be used to reconstruct past variations in the operation of the carbon cycle, as well as changes in ocean circulation. Nevertheless, understanding the link between these sediment variables (or proxies') and environmental conditions is not straightforward. This volume adopts a novel approach by bringing together palaeontologists, geochemists and palaeoceanographers, who contribute evidence that is required to better constrain these proxies. Topics include: (i) processes of biomineralization, and their effect on the chemical and isotopic composition of different organisms; (ii) proxy validation, including field, laboratory and theoretical studies; (iii) the links between modern and fossil organisms.

Description: We investigated the plumbing system of Stromboli volcano from the upper mantle to the surface. Thermobarometric estimates indicate that the deeper detected part of the plumbing system is located in the upper mantle, at approximately 34-24 km depth where, during their ascent, primitive Stromboli basalts (HKCA to shoshonitic) interact with peridotitic materials. In this region magma flow is probably channelled along fracture zones that may converge into a feeder dyke that crosscuts the Moho at about 17 km depth. During their ascent, basaltic magmas will interact with lower crust materials represented by cumulates of earlier Stromboli-type basalts at 13-10 km depth. This zone is also the section of the plumbing system where the feeder dyke is entering the chamber. Thermobarometric estimates, obtained by constructing a grid of selected reactions, indicate that current primitive Stromboli basalts equilibrate at 0.3-0.15 GPa and temperatures approaching 1200 {degrees}C, and progressively crystallize and degas before being erupted. Crystal size distributions on lavas and juvenile tephra erupted in 2002-2003 give very variable residence times. Based on average bubble distances, the estimated times for the exsolution of the gaseous phases range from 2-7 days to 45 min for the lavas and scorias, down to about 15 h to 12 min for the pumices erupted during paroxysmal explosions. Estimated syneruptive viscosities range from 102 Pa s for the anhydrous basaltic pumices at 1200 {degrees}C, to 103-104 Pa s for lavas approaching their effusion temperatures (1100-1150 {degrees}C). In turn, viscosities for the hydrous basaltic melt that led to the formation of the basaltic pumices may be around 10 Pa s or lower. In the light of the above, we discuss the possible shapes and volumes of Stromboli magma chamber by considering a sphere, an ellipsoid (geometrically concordant with the regional stress distribution) and a feeder dyke, the last two being more likely. In the light of volcanological, structural and geophysical data on conduit thickness, we propose an alternative model that takes into account the volumes of recently erupted lavas. This model consists of a convective ellipsoidal magma chamber injected' by an active feeder dike of undegassed magma of higher temperature, lower density and lower viscosity. This dyke will evolve into a magma column inside the chamber and will separate the reservoir into two lateral, nearly symmetric convective regions. Crystallization would occur preferentially in the proximity of the wallrocks, particularly where the chamber is entering the conduit. The onset of paroxysmal explosions during major effusive cycles may be explained by a drastic increase in the intrusion rates at the base of the chamber that will produce a progressive inflation of the magma column dynamically transferred to the chamber walls. The ceasing of anomalous' intrusion rates at the base of the chamber, coupled with higher discharge rates, will progressively depressurize the chamber to a critical threshold, until the stress transferred to the walls is dynamically released: at this point the walls themselves will undergo a nearly instantaneous elastic rebound and contract in the attempt to recover their original pre-eruptive geometry. These dynamics will squeeze up portions of the undegassed magma column, triggering a paroxysmal explosion with the ejection of golden pumices'.

Description: The spatial distribution of extensional strain in interbedded mudstones and carbonates from around Kimmeridge Bay in southern England is examined using a variety of line samples. Normal faults and tensile fractures (veins) from the same deformation event show displacements ranging over 6 orders of magnitude. The relative contribution of these structures to the overall extension varies, with large faults (〉10 m heave) accommodating about 65%, smaller faults (1-10 m heave) about 25% and veins less than 10% of the overall extension. The heterogeneity of fracture density and strain can be quantified from cumulative plots by applying a non-parametric method based on Kuiper's test. Both the degree and statistical significance of strain heterogeneity can be determined and are shown to be scale-dependent. Thin veins accommodate a fairly constant background strain across the region, whilst thick veins and small faults take up localized higher strains in damage zones around larger faults. Fault-strain is relatively homogenously distributed across the region. The faults and veins do not share the same scaling relationship. Thus, this study shows that it is not possible to simply extrapolate fracture frequencies and strain from fault scale to vein scale, and that the heterogeneity of extensional strain is scale dependent.

Description: We focus on movement of magma beneath K[i]lauea from the long summit eruption in 1967-1968 through the first historical sustained eruption on the east rift zone (Mauna Ulu 1969-1974), ending with the occurrence of a magnitude 7.2 earthquake beneath K[i]lauea's eastern south flank. Magma from the Hawai iian hot spot continuously moves upward to summit storage and drives seaward spreading of K[i]lauea's south flank on a 10-12 km deep decollement. Spreading creates dilation in K[i]lauea's rift zones and provides room to store magma at depths extending to the decollement surface. During the period of study three types of eruptions - normal (short-lived), episodic and sustained - and three types of intrusions - traditional (summit to rift), inflationary and slow - are classified. Rates of sustained eruption are governed by the geometry of the magmatic plumbing. Swarms of earthquakes beneath the south flank signal increased pressure from magma entering K[i]lauea's adjacent rift zone. Magma supply rates are obtained by combining the volume of magma transferred to sites of eruption or intrusion with the volume opened by seaward spreading over the same increment of time. In our interpretation the varying character of eruptions and intrusions requires a gradual increase in magma supply rate throughout the period augmented by incremental increases in spreading rate. The three types of eruptions result from different combinations of magma supply and spreading rate.

Description: Crystals are rarely composed of a single crystal population that have grown solely from the batch of magma in which they are resident on emplacement, either by eruption or shallow intrusion. Close investigation of the majority of crystal populations reveal that they comprise up to four main components: phenocrysts, crystals co-genetic with their magmatic host; xenocrysts, crystals wholly, or in part, foreign to the magmatic host and magma system; antecrysts, crystals which are recycled one or several times before inclusion in the host magma but have an origin within the magmatic system; and microlites, which represent small co-genetic crystals which nucleate and grow rapidly on decompression and eruption. Textural analysis techniques are employed to quantify key aspects of the crystal population, including crystal shape, crystal size distributions, spatial distribution patterns and textural modification using dihedral angles. Santorini provides a case study of an active volcanic system where a combined textural analysis study has been developed, highlighting how the crystal population is being continuously modified by a series of replenishment and mixing events. Developing textural and microgeochemical techniques provides the next stage in the interrogation of crystal populations, linking textures to isotopic heterogeneities and providing fingerprints of where crystals are sourced and re-cycled.

Description: The origins of geoconservation cannot be investigated without first defining its scope. This presents a problem because there is no established working definition of the field. By using the Giant's Causeway as a case study, useful parameters were identified revealing great complexity. They embrace initial curiosity, scientific communication, mythology, access issues, the involvement of national scientific institutions, controversial but ultimately successful iconography, the invention of new artistic conventions, dissemination by engraving, scientific reaction, rekindling of a fundamental geological controversy, tourism, popular literature, modes of transport, commercialization, additions to fundamental science, designation history and historic associations of the site. Other sites are similarly complex and assist in refining the scope. Sites are seen as the principal resource but on analysis achieve their status from what they reveal or the importance of the materials they yield, in turn spotlighting the major museum collections. These are now well documented though not all are secure. It was not the scientific imperative that established the first public designation but an impassioned delight in unspoiled nature which three men, two Americans, Henry Thoreau and George Marsh but especially the Scots environmentalist, John Muir, projected carefully into the attuned ear of the US President. This brief overview closes with the revelation of neglected areas of heritage, paths that geoconservation could have taken and still may and suggests how earlier definitions could be elevated into a more specific and holistic geoconservation strategy.

Description: Before the middle of the twentieth century there were very few geological reserves in Britain and there was no government legislation to protect them. In other countries and especially in the USA, there were many more such sites protected by a number of legislative processes. In nineteenth century Britain most of the land was owned by comparatively few wealthy people and common land was being steadily reduced through increasing numbers of Enclosure Acts. This meant that there were very few opportunities for conservation action especially as there was no legal basis for doing so other than through land ownership. In the USA the situation was completely different. The westward expansion was in full swing resulting in an increasing amount of federal land holdings owned by Congress. This, together with a desire of the federal government to save special sites for future generations, resulted in the extensive National Parks created by statute and the cultural and national monuments protected by the 1906 Preservation of American Antiquities Act. It took another forty years for Britain to have similar legislation.

Description: Geodiversity' can be defined as the range of geological, geomorphological and soil features. Although the word itself was first used only in the early 1990s, the principles behind its application to nature conservation have a longer history. For example, the search for representative sites has been a guiding principle for conservation site selection in the UK since the Second World War, and can also be detected as the basis for new site selection criteria in the USA, Ireland and many other countries. It is also starting to be used as a means of analysing the existing World Heritage Sites list and may become one factor in assessing new site applications. The word was first widely adopted in Tasmania and has a status equal to biodiversity within the Australian Natural Heritage Charter. Despite some opposition, the term is increasingly being used around the world, but has been adopted most enthusiastically in the UK, where many Geodiversity Audits, Local Geodiversity Action Plans and Company Geodiversity Action Plans have been published or are planned. A national Geodiversity Action Plan will be published in 2008. The term has also been adopted in national planning guidance in the UK and, as a result, is finding its way into regional and local planning policies. The paper concludes with some speculations about its future use in geoconservation.

Description: The role of the voluntary sector in geoconservation has a long history. However, its involvement in biodiversity conservation is even longer. A contrast is made between the biodiversity and geodiversity voluntary sectors through time. With the start of the movement arguably by the National Trust in the late nineteenth century, the baton (or hammer) has been taken up by geological societies locally and nationally, by individuals and more recently by the RIGS initiative. The word voluntary in no way diminishes the work undertaken and achieved by these people. It can be argued that without them geoconservation would not exist. This paper explores their contribution using case studies: National Trust and UKRIGS as national organizations, the RIGS movement as a local initiative, the Chester Society of Natural Science as local' interest and the work of individuals through time. The latest Local Geodiversity Action Plans (LGAPs) development as a recent historical phenomenon is explored and the importance of local as context for geoconservation illustrated.

Description: England, and the UK more widely, have robust and mature statutory and voluntary frameworks for delivering geoconservation. Critical to achieving this advanced position was the inclusion of geoconservation within the first nature conservation legislation enacted in Britain in 1949. The development of this legislation benefited greatly from the wisdom of a number of committees set up to inform government thinking. Many of these committees were advised by the scientific community, including geologists and geomorphologists. The work and influence of these committees in establishing geoconservation as part of statutory nature conservation is explored, and the main statutory and policy milestones which have guided and shaped geoconservation in England since 1949 are described. The rise of the voluntary geoconservation movement in the late 1980s is also explored.

Description: The intra-oceanic Izu Bonin arc (NW Pacific) has produced a bimodal spectrum of melts with maxima in the basaltic andesitic (c. 53-54 wt% SiO2) and rhyolitic range (c. 70-72 wt% SiO2) since arc inception c. 48-49 million years ago. Composition of phenocrysts and accessory minerals from 21 contemporaneous fallout tephras from ODP Site 782A confirm the bimodality and uniformity of the erupted melts. The basaltic andesite melts equilibrated with calcic plagioclase (c. An70-95), high-Mg# clino- and orthopyroxene and low-Ti titanomagnetite. Dacitic and rhyolitic melts crystallized sodic plagioclase (c. An40-60), low-Mg# clino- and orthopyroxene, apatite, Ti-rich titanomagnetite in addition to occasional ilmenite and amphibole. The Izu melts are inferred to crystallize at oxygen fugacities between c. 0 to +2.5 log10 units relative to FMQ, at temperatures between c. 775{degrees} and 1100 {degrees}C and at pressures between c. 300 and c. 1100 MPa, corresponding to c. 5-35 km lithospheric depth. The compositional uniformity of the tephra layers, which are spaced on average 230 {+/-} 380 ka apart, suggest uniform processes of differentiation since at least c. 42 Ma ago. The tephra record shows no indication of periodic or progressive crustal growth that might correlate with the alternate periods of arc formation, arc rifting or backarc spreading, or would suggest an increasingly efficient crustal filter' with time. The tephra data tentatively conform to a model where crust grows steadily through intrusions of mafic and evolved melt body batches whereby buoyancy controls the level of solidification. While the tephra compositions demonstrate the uniformity of the processes of melt formation and differentiation through time, the data do not permit the differentiation processes themselves to be constrained. These may comprise fractional crystallization, crustal fusion, fusion of non-peridotitic sub-crustal lithologies, or any combination of these processes.

Description: This collection of papers addresses the issues surrounding communication of environmental geoscience. Geologists whose research deals with environmental problems such as landslides, floods, earthquakes and other natural hazards that affect people's health and safety, must communicate their results effectively to the public, policy makers and politicians. There are many examples of geological studies being ignored in policy and public action; this is in due in part to geoscientists being poor communicators. These papers document issues in communicating environmental geoscience, outline successes and failures through case studies, describe ways in which geoscientists can improve communication skills and show how new methods can make communication more effective.

Description: This collection of papers is aimed primarily at the environmental geoscientist faced with the challenges of communicating important scientific results to those who might benefit from them, whether they are politicians, policy-makers, potential victims of geological disasters, fellow scientists or other members of the public. Environmental geoscience has grown to become one of the most important disciplines of geoscience as a whole, and scientific methods of investigation have become sophisticated and effective at addressing numerous problems that directly affect health and safety. The audience for such research thus is wide, and for such research to be used in the most effective manner requires well-developed communication skills to reach an audience that varies greatly in education and ability to comprehend scientific concepts. The implications of failing to communicate effectively may be severe: geological disasters have had a massive economic and social impact, with major loss of life.

Description: The current volume samples a selection of papers presented at the Geological Society of London meeting on ‘Biogeochemical Controls on Palaeoceanographic Proxies’, held at Burlington House, London, UK on 3–4 October 2005. The aim of the meeting was to bring together palaeontologists, geochemists and palaeoceanographers who could contribute evidence that, when considered together, would better constrain the proxies that are used for palaeoclimate reconstruction. An improved understanding and quantification of past climate change, and the processes that force climate to change, has a fundamental role to play in constraining model projections of future climate (e.g. Hegerl et al. 2006) but it remains a huge challenge. This is because key climate variables, such as temperature and ocean salinity, cannot be observed in a world which no longer exists, but must instead be teased from proxies in the geological and ice records. There are numerous proxy archives, but one of the most important, currently lying at the forefront of palaeoceanographic research, is the biogeochemical composition of sediment records. This publication consists of 11 papers which deal with various aspects of biogeochemical proxies and their interpretation in terms of past climate. Seven of these specifically focus on the Foraminifera. What are proxies? Primarily, these are biogenic components which have a close relationship to environmental parameters and may be identified as so-called ‘proxy variables’ (Wefer et al. 1999), providing measurable descriptors of key climatic and environmental variables. The methods commonly employed in palaeoceanography have ...

Description: The mild compressional structures of Cenozoic age on the passive margins bordering Norway, the UK, the Faroes and Ireland have been the subject of much discussion in the literature. Nevertheless, their origin remains enigmatic. Candidate mechanisms must be able to explain the generation of sufficient stress to cause deformation, the episodic nature of the structures and why they developed where they did. We examine these mechanisms and conclude that multiple causes are probable, while favouring body force as potentially the most important agent. The geometry and setting of the structures are incompatible with gravitational sliding and toe-thrusting, probably the commonest compressive' structuring around the Atlantic margins. A passive mode of origin featuring drape or flank sedimentary loading probably emphasized some of the structures, but cannot be invoked as a primary mechanism. Likewise, reactivation of basement structure probably focused deformation but did not initiate it. Far-field orogenic stress from Alpine orogenic phases and from the West Spitsbergen-Eurekan folding and thrusting is also examined. This mechanism is attractive because of its potential to explain episodicity of the compressional structures. However, difficulties exist with stress transmission pathways from these fold belts, and the passive margin structures developed for much of their existence in the absence of any nearby contemporaneous orogeny. Breakup and plate spreading forces such as divergent asthenosheric flow have potential to explain early post-breakup compressional structuring, for example on the UK-Faroes margin, but are unlikely to account for later (Neogene) deformation. Ridge push, generally thought to be the dominant body force acting on passive margins, can in some circumstances generate enough stress to cause mild deformation, but appears to have low potential to explain episodicity. It is proposed here that the primary agent generating the body force was development of the Iceland Insular Margin, the significant bathymetric-topographic high around Iceland. Circumstantially, in Miocene times, this development may also have coincided with the acme of the compressional structures. We show that, dependent on the degree of lithosphere-asthenosphere coupling, the Iceland Plateau may have generated enough horizontal stress to deform adjacent margins, and may explain the arcuate distribution of the compressional structures around Iceland. Assuming transmission of stress through the basement we argue that, through time, the structures will have developed preferentially where the basement is hotter, weaker and therefore more prone to shearing at the relatively low stress levels. This situation is most likely at the stretched and most thermally-blanketed crust under the thickest parts of the young (Cretaceous-Cenozoic) basins. Although several elements of this model remain to be tested, it has the potential to provide a general explanation for passive margin compression at comparatively low stress levels and in the absence of nearby orogeny or gravitational sliding.

Description: Metabasites from the Lutzow-Holm Complex, East Antarctica, are the equivalent of metamorphosed ultramafic and mafic rocks with ultrabasic to intermediate compositions, which occur as layers and blocks in the quartzo-feldspathic or metasedimentary gneisses. Field occurrences and whole-rock geochemistry suggest that the ultramafic rocks are all cumulitic protoliths, whereas the mafic rocks are mostly basaltic protoliths including some cumulates. Moreover, in a regional context, the geochemistry of metabasites shifts from island arc to ocean-floor affinities in a southwesterly direction from the Prince Olav Coast to the Lutzow-Holm Bay area. Neodymium isotopic data suggest that the metamorphic rocks from the Prince Olav Coast and the northern Lutzow-Holm Bay areas were derived from immature continental crust formed by active Mesoproterozoic crustal growth, whereas those from the southern Lutzow-Holm Bay area were derived from mature continental crust and oceanic crust of older age. Thus, these results suggest that the Lutzow-Holm Complex includes lithological units with various origins and ages that were amalgamated by multiple subduction, and underwent high-grade metamorphism as a result of the final collision of East and West Gondwana during the Pan-African orogeny.

Description: The region comprising central to eastern Dronning Maud Land (2{degrees}W to 40{degrees}E), East Antarctica, is underlain by Mesoproterozoic to Cambrian metamorphic rocks and post-kinematic intrusive rocks with varied compositions. The post-kinematic mafic dykes linked to the Pan-African orogen include various types of lithologies: lamprophyre and lamproite in Muhlig-Hofmannfjella in central Dronning Maud Land and lamprophyre and high-K dolerite in the Sor Rondane Mountains in eastern Dronning Maud Land. Most of the mafic dykes have been weakly affected by low-grade metamorphism, but clearly preserve their igneous textures. The mafic dykes show a high abundance of Rb, Ba, Sr and light rare earth elements with negative anomalies of Nb, Ta and Ti in a multi-element primitive mantle-normalized diagram. The geochemical characteristics of the mafic dykes suggest that they were derived from a metasomatized mantle source leaving phlogopite, rutile and/or titanite as residual phases. Considering Sr and Nd isotopic systematics of the mafic dykes and the host metamorphic rocks and coeval felsic intrusive rocks, a large crustal boundary potentially related to a suture zone of West and East Gondwana should pass between Muhlig-Hofmannfjella and the Sor Rondane Mountains.

Description: This paper presents a form-line map of the Napier and Rayner Complexes, East Antarctica, constructed from attitude data for foliations shown on published geological maps, and discusses the macroscopic geological structures. The form-line map shows that the two complexes consist of several, structurally distinct, units or blocks bounded by east-west-, NE-SW- and NW-SE-striking faults. The major boundary between the two complexes, as indicated on the published geological maps, is a structural discontinuity shown as a large fault on the form-line map. On the form-line map, east-west- and NE-SW-trending folds are abundant and NW-SE-trending ones occur locally in both complexes. North-south-trending folds are also abundant in the Napier Complex. Dome-and-basin fold patterns on a regional scale occur in some regions. The regional strikes, macroscopic structures, and the major boundary between the two complexes are considered to have resulted from the same later deformation episode. The form-line map and distribution map of key mineral assemblages show that the Napier Complex is not uniform and includes at least two types of metamorphic units or fragments of the Archaean crust that were formed through distinct P-T-t evolutionary processes and divided by several faults.

Description: Geological correlations of East Antarctica with adjoining continents have been puzzling geologists ever since the concept of a Gondwana supercontinent surfaced. Despite the paucity of outcrops because of ice cover, difficulty of access and extreme weather, the past 50 years of Japanese Antarctic Research Expeditions (JARE) has successfully revealed vital elements of the geology of East Antarctica. This volume presents reviews and new research from localities across East Antarctica, especially from Dronning Maud Land to Enderby Land, where the geological record preserves a history that spans the Archaean and Proterozoic. The reviews include extensive bibliographies of results obtained by geologists who participated in the JARE. Comprehensive geological, petrological and geochemical studies, form a platform for future research on the formation and dispersion of Rodinia in the Mesoproterozoic and subsequent assembly of Gondwana in the Neoproterozoic to Early Palaeozoic.

Description: Emplacement of post-tectonic Early Palaeozoic pegmatites on Tonagh Island, Napier Complex, East Antarctica, was accompanied by the introduction of aqueous low-salinity fluids at mid-P upper-amphibolite facies conditions (c. 8 kbar, c. 680 {degrees}C). Fluid-wall-rock interaction resulted in the development of spectacular alteration selvedges, in the immediate vicinity of the pegmatites, in adjacent Archaean orthogneisses. Archaean wall-rocks affected by the infiltration of aqueous fluids show contrasting patterns of K, Na and Ca metasomatism, which we demonstrate was fundamentally controlled by disequilibrium of invading fluids with wall-rock feldspars, rather than fluid flow up or down regional pressure or temperature gradients. Other species, such as the rare earth elements (REE; except Eu), Y, P, Rb, Th, U and Pb, for example, show significant enrichment in the metasomatized wall-rock in both examples studied. Enrichment of P (and Y), sympathetic with that of REE enrichment, is consistent with recent suggestions that REE transport in fluids may be enhanced by complexing with dissolved P and Y compounds. Dehydration and partial melting of previously unmetamorphosed sedimentary rocks, underthrust beneath the SW Napier Complex, has been long considered a viable source for felsic pegmatites (and associated fluids) observed in that region. Our results are consistent with the hypothesis that underplated sedimentary rocks were a viable source for pegmatite melt and aqueous fluids. Furthermore, as our study demonstrates a plausible relationship between Early Palaeozoic (c. 500-530 Ma) pegmatites and fluid infiltration, we suggest that dehydration and prograde partial melting of the underthrust sedimentary rocks beneath the Napier Complex occurred, at least in part, by convergent Early Palaeozoic tectonism.

Description: Ultrasonic measurements of P-wave velocity (Vp) and S-wave velocity (Vs) were conducted at high pressures up to 1.0 GPa and high temperatures up to 400 {degrees}C for ultrahigh-temperature (UHT) metamorphosed rocks from Mount Riiser-Larsen, in the Archaean Napier Complex of Enderby Land. The results at 1.0 GPa and 400 {degrees}C are Vp=7.17 km s-1, Vs=4.24 km s-1, Vp/Vs=1.69, Poisson's ratio ({sigma})=0.23 for pyroxenite (SiO2=44.2 wt%, density ({rho})=3.41 g cm-3); Vp=6.93 km s-1, Vs=3.81 km s-1, Vp/Vs=1.82, {sigma}=0.28 for mafic granulite (SiO2=52.2 wt%, {rho}=3.02 g cm-3); Vp=6.88 km s-1, Vs=3.72 km s-1, Vp/Vs=1.85, {sigma}=0.29 for mafic granulite (SiO2=49.5 wt%, {rho}=2.88 g cm-3); and Vp=6.17 km s-1, Vs=3.59 km s-1, Vp/Vs=1.72, {sigma}=0.24 for orthopyroxene-bearing felsic gneiss (SiO2=65.4 wt%, {rho}=2.68 g cm-3). Vp and Vp/Vs of these UHT rocks are not comparable with the previously proposed seismic velocity model (Vp=6.56 km s-1, Vp/Vs=1.70) for the lower crust beneath the Mizuho Plateau of eastern Dronning Maud Land. Combining the available measured velocity and density data with the seismic velocity profile defined for the Mizuho Plateau, we suggest that relatively low Vp and Vs characteristics of the lower crust beneath the Mizuho Plateau may be attributed to higher abundance of biotite in the mafic lower crustal rocks. It is proposed that the biotite-bearing lower crustal rocks were formed by metasomatic processes associated with Pan-African orogeny.

Description: Data for the period 1821 to 2003 from 126 rain gauges, 41 temperature gauges, eight river discharge gauges and 239 wells, located in southern Italy, have been analysed to characterize the effect of recent climate change on availability of water resources, focusing on groundwater resources. Regular data are available from 1921 to 2001. Many analysis methods are used: principal component analysis, to divide the study area into homogenous portions; trend analysis, considering the MannKendall, Student-t and Craddock tests, autocorrelation and cross-correlation analyses, and seasonal, annual and moving-average variables, applying the spatial analysis to each variable with a geographical information system approach. A widespread decreasing trend of annual rainfall is observed over 97% of the whole area. The decreasing trend of rainfall worsens or decreases as mean annual rainfall increases; the spatial mean of trend ranges from 0.8 mm/a in Apulia to 2.9 mm/a in Calabria. The decrease in rainfall is notable after 1980: the recent droughts of 19881992 and 19992001 appear to be exceptional. On a seasonal basis, the decreasing trend is concentrated in winter; a slight positive trend is observed in summer, the arid season in which the increase is useless as it is transformed into actual evapotranspiration. The temperature trend is not significant and homogeneous everywhere if the temperature increase seems to prevail, especially from about 1980. Net rainfall, calculated as a function of monthly rainfall and temperature, shows a huge and generalized negative trend. The trend of groundwater availability is so negative everywhere that the situation can be termed dramatic for water users, due not only to the natural drop in recharge but also to the increase of discharge by wells to compensate the non-availability of surface water tapped by dams, as a direct effect of droughts.

Description: Extreme climate conditions are expected in the twenty-first century in the form of higher maximum temperature (with more hot days) resulting in frequent droughts. The continents of Africa and Asia are anticipated to be extremely vulnerable to droughts. In the impending extreme climate conditions, humanity's sustenance hinges on groundwater as it forms the world's largest freshwater resource. Adaptive and mitigation measures entail well planned strategies for sustained groundwater through extreme climate conditions including droughts. In this paper two such strategies are discussed to overcome the problem of droughts: (i) artificial groundwater recharge using percolation ponds; and (ii) identifying and characterizing deep aquifers resilient to droughts through detailed geophysical, hydrogeological and isotopic studies. Percolation ponds act as artificial recharge structures which are constructed across monsoon streams with the purpose of harvesting surface runoff caused by monsoon streams. Conventional and tracer methods were developed in India to determine how effective these artificial recharge structures could be. From studies carried out on percolation ponds located in diverse geological formations such as granites, basalts and sandstones, it was concluded that these structures are quite useful for overcoming droughts in semi-arid and arid regions, and it was demonstrated that the role of geology outweighs the effect of climate on such structures. It has been shown that in a similar climatic environment, the percolation ponds in sandstones were far more efficient (efficiency 60%) than those in basalts (efficiency 2030%). Recently it has been realized that certain deep aquifers can yield a good quantity and quality of water even during extreme climate events. The Neyveli aquifer in southern India has been demonstrated to be such a representative aquifer for mitigation of droughts. Very extensive and intensive hydrogeological and isotopic studies on the aquifer revealed that the aquifer has distinct characteristics, namely: (i) distinct recharge area; (ii) extensive groundwater regime with high degree of recharge rate; (iii) wide span of radiocarbon ages from Modern to 〉30 000 years BP indicating modern as well as palaeorecharge; and (iv) minimal changes in groundwater quality despite very heavy and continuous withdrawal during the last four decades. All these criteria provide the necessary ingredients for drought resilient aquifers which can be used to identify similar aquifers elsewhere in the world.

Description: Accurately positioning faults in a geological model is a major concern because they are responsible for offsets of geological sequences. In the tetrahedral models studied in this paper, faults are discontinuities: faces of tetrahedra on either side of a fault are disconnected. Building tetrahedral models can require a large amount of time, especially when there are many faults. We present a tool for making small, real-time, modifications of faults in tetrahedral models arising from geometrical changes required either by new subsurface data or by new interpretations of existing subsurface data. Fault editing is achieved by moving control points on the fault in the tetrahedral grid and by computing a distortion property over an editable volume relative to the control point and spreading this distortion to neighbouring points using the Discrete Smooth Interpolation technique. The editable volume in which tetrahedron vertices are allowed to move is defined by a given distance to the fault. This approach provides a means of editing faults and fault-related features, such as branch-lines.

Description: A geomechanical method is presented for the prediction of subseismic fracture intensity associated with faulting using a boundary element model conditioned from 3D seismic interpretation within the Green River Basin, Wyoming, USA. Seismic data indicate two major phases of deformation: (1) an early phase of approximately ESE-verging contraction accommodated along a NNESSW striking system of basement-involved reverse faults and associated drape folds; and (2) a later phase of transtension accommodated by ENEWSW-trending normal faults that are preferentially located in the hanging wall, above the crest of the drape fold. The models predict different spatial patterns of fracture intensity for each phase of deformation. For D1, enhanced probability for shear failure develops in the upper quadrant of the footwalls along the reverse faults (i.e. forelimb) and the greatest magnitudes occur adjacent to regions with the largest component of observable dip-slip displacement along the faults. During D2, enhanced probability for joint and fault formation occurs along-strike of the normal faults and in a general NE trend. Seismic velocity anisotropy data support the geomechanical predictions for both phases of deformation in that the location and azimuth of large anisotropies correlate with regions of predicted enhancement in joint and fault intensity.

Description: Mechanical stratigraphy exerts a first-order control on deformation at a range of scales from oilfield-scale structural style to deformation (e.g. fracturing) within an individual reservoir stratum. This paper explores an outcrop example where mechanical stratigraphy in a limestone and shale sequence directly influenced the structural style and distribution of deformation related to the propagation of a seismic-scale' normal fault that has maximum displacement on the order of 100500 m and extends for more than 10 km. A monocline developed in Cretaceous Buda Limestone above tectonically thinned Del Rio Clay and faulted Santa Elena Limestone is here interpreted as an extensional fault propagation fold. Monocline limb dips reach 59{degrees}. The Del Rio Clay is thinned from approximately 36 m to 1.5 m, whereas the underlying Santa Elena Limestone is offset vertically by approximately 74 m along a steep (approximately 80{degrees}) normal fault. This large fault displacement of the Santa Elena Limestone is not transferred upward to the Buda Limestone because of ductile flow within the intervening Del Rio Clay. Although upward fault propagation has been inhibited, thinning of the Del Rio Clay and the resultant extreme displacement gradient at the tip of the fault have forced the Buda Limestone into a monoclinal fold. Two competent packstone and grainstone beds, 6 m and 2.7 m thick and separated by 10.5 m of less competent calcareous shale, comprise the Buda Limestone at this location. Deformation features within the competent Buda beds include bed-perpendicular veins that accommodate bed-parallel extension, and bedding plane slip surfaces with an up-dip sense of shear that offset the veins. Deformation is concentrated in the monoclinal limb and not in the monoclinal hinge regions. Consequently, bed-parallel extension and shear strain are associated with monoclinal dip, not with curvature. These results show that for this structure, bed dip is a better proxy for bed-parallel extension and related fracture dilation than is curvature.

Description: Post-depositional normal faults within the turbidite sequence of the Late Miocene Mount Messenger Formation of the Taranaki Basin, New Zealand are characterized by granulation and cataclasis of sands and by the smearing of clay beds. Clay smears maintain continuity for high ratios of fault throw to clay source bed thickness (c. 8), but are highly variable in thickness, and gaps occur at any point between the clay source bed cut-offs at higher ratios. Although cataclastic fault rock permeabilities may be appreciably lower (c. two orders of magnitude) than host rock sandstone permeabilities, the occurrence of continuous clay smears, combined with low clay permeabilities (10s to 100s nD) means that the primary control on fault rock permeability is clay smear continuity. A new permeability predictor, the Probabilistic Shale Smear Factor (PSSF), is developed which incorporates the main characteristics of clay smearing from the Taranaki Basin. The PSSF method calculates fault permeabilities from a simple model of multiple clay smears within fault zones, predicting a more heterogeneous and realistic fault rock structure than other approaches (e.g. Shale Gouge Ratio, SGR). Nevertheless, its averaging effects at higher ratios of fault throw to bed thickness provide a rationale for the application of other fault rock mixing models, e.g. SGR, at appropriate scales.

Description: The alkaline lamprophyres and diabases from the Spanish Central System carry a heterogeneous suite of xenoliths including a group of highly altered ultramafic pyroxenites that contain CrMg-rich high-T hydrous minerals (Ti-phlogopite and pargasitic to kaersutitic amphibole), indicative of modal metasomatism. The trace element mineral compositions of these xenoliths show three patterns: type A xenoliths, with light rare earth element enriched clinopyroxenes with high field strength element (HFSE) negative anomalies; type B xenoliths, with clinopyroxenes and amphiboles with high incompatible trace element contents (large ion lithophile elements (LILE), HFSE and REE); type C xenoliths, with relatively REE- and HFSE-poor clinopyroxenes and amphiboles. These metasomatic signatures suggest the involvement of three different metasomatic agents: carbonate, silicate and hydrous fluids or melts, respectively. These agents could have been derived from the progressive differentiation of a CO2H2O-rich highly alkaline magma, genetically related to the Late Permian alkaline magmatism. Because of the original sub-alkaline nature of the pyroxenite xenoliths, they might have been formed originally as pyroxene-rich cumulates associated with underplated Hercynian calc-alkaline basic magmas. Metasomatism as a result of the infiltration of alkaline magmas within these cumulates might explain the relatively high radiogenic Nd composition of the altered ultramafic xenoliths.

Description: In the foreword of the volume Mantle Metasomatism by Menzies & Hawkesworth (1987), Boettcher stated that the concept of mantle metasomatism has been of immense heuristic value for Earth scientists. At that time, metasomatism was still strongly related to allochemical metamorphism, where chemical composition of the rock is changed by the additional or removal of material. However, the concept of modal or patent (where a new phase is petrographically evident) and cryptic (where chemical enrichment is not accompanied by the presence of a newly formed phase) metasomatism had already been introduced by the pioneering works of Harte (1983), Menzies (1983) and Dawson (1984). Outstanding progress has characterized the past two decades, and the processes and agents of metasomatism are now much better understood, in part as a result of the significant advancements of in situ microanalytical techniques such as secondary ionization mass spectrometry (SIMS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The in situ analyses substantially deepened knowledge of intermineral and solid

Description: Coarse-grained, protogranular spinel peridotite xenoliths in the Upper Miocene Valle Guffari diatreme display a complex history for the shallow mantle underneath the Hyblean Plateau (SE Sicily). The mineral assemblage and composition (olivine Fo8991, orthopyroxene En8891, Cr-diopside En4849Fs46Wo4548, Cr-rich spinel with cr-number=2539) record at least one depletion event caused by melt extraction, followed by metasomatic enrichment. One of these samples (HYB40) hosts a fresh glass vein. Rare earth elements (REE) in clinopyroxenes from these peridotites show three patterns: (1) light REE-enriched (Lan/Ybn=717); (2) spoon-shaped (Lan/Ybn=1820; Lan/Smn=2134; Smn/Ybn〈1); (3) nearly flat (Lan/Ybn [~]3). Whole-rock and clinopyroxene trace elements indicate that these patterns are associated with more or less complete equilibration with at least two distinct metasomatic melts: an alkaline silicate melt resembling the host basalt and a hawaiitic melt (for peridotite HYB40). PT estimates yield 0.91.2 GPa and 8701050 {degrees}C, suggesting that refertilization by metasomatizing melts occurred at the CrustMantle boundary or just below. In addition, the PT data coincide with the palaeogeotherm reported by an earlier worker that is consistent with a high geothermal gradient. However, this thermal regime does not fit with the occurrence of an active mantle plume beneath the Hyblean area because of the deduced mantle potential temperatures, which are almost 200{degrees}C lower than those typical for a mantle plume. fO2 calculation gives a redox state above the fayalitemagnetitequartz buffer FMQ (up to +1.7 {Delta}log units) related to melt-driven metasomatism.

Description: Mantle xenolith bearing olivine melanephelinites from the Okhotsk sector of the OkhotskChukotka Volcanic Belt (OCVB), northeastern Russia, occur as small isolated volcanoes emplaced within massive late Early to Late Cretaceous subduction-related calc-alkaline rocks. The xenoliths are typical medium- to fine-grained anhydrous mainly spinel lherzolites that are strongly to weakly foliated with intensive to minor recrystallization to equigranular texture. The primitive mantle normalized whole-rock REE have flat patterns or patterns with slightly elevated light REE (LREE) ((La/Yb)N=0.481.38). The REE in clinopyroxenes have systematically decreasing normalized abundances from Sm to La, implying that the LREE enrichments in the whole-rock REE patterns are attributed to circulation of minor intergranular fluids or melts. Equilibration temperatures and pressures calculated for the Viliga samples are in the range of 10501160 {degrees}C and 1521 kbar, respectively. Ca diffusion rates in olivine reveal a rapid transport to the surface (26 days) of these peridotites. Model calculations have shown that the fertile lherzolites can be produced by 29% batch melting, whereas the depleted peridotites require 15% batch melting of a primitive source. The cessation of the interaction between the palaeo-Pacific plate and the NE Russian margin at c. 87 Ma apparently caused a piecemeal' collapse of the former followed by intrusion and ascent of olivine melanephelinitic magma, which entrained xenoliths from the asthenospheric mantle of the subducted plate during the Pliocene through the generated window(s). Moreover, clinopyroxenes that have low 87Sr/86Sr and high 143Nd/144Nd and plot in and above the mid-ocean ridge basalt (MORB) field are consistent with an upwelling asthenospheric mantle through the window(s) created by the piecemeal' collapse of the palaeo-Pacific plate.

Description: A 530490 Ma tectono-metamorphic event, the Buzios orogeny, is recognized within the Ribeira Belt, along the coast of SE Brazil. Tectonic evolution started with a Late Neoproterozoic marine basin and volcanic activity at c. 610 Ma. The rocks in this basin were affected by high-grade metamorphism at c. 530 Ma, coeval with deformational phases D1D2, which generated compressive low-angle tectonic structures with top-to-NW tectonic transport. Large recumbent folds with NWSE axes parallel to the main stretching lineation formed during D3 as the Cabo Frio tectonic domain, the focus of this study, collided with the Oriental terrane to the NW. D4 sub-vertical shear zones are limited in extent. A new UPb age of 501{+/-}6 Ma is reported for zircon from an amphibolite-facies shear zone related to either D3 or D4. Post-tectonic 440 Ma pegmatites mark the final stage of tectono-magmatic activity. The Cabo Frio tectonic domain has African affinities and is exotic to the Ribeira Belt. Middle Cambrian deformational and metamorphic ages are also reported from the Angolan' Pan-African belt, the southern Kaoko and Damara belts in Namibia, and the Cuchilla DionisioPunta Del Este terrane in Uruguay. The occurrence of Cambrian metamorphic rocks along the present African and South American coastlines shows that Mesozoic rifting closely follows Palaeozoic sutures of West Gondwana.

Description: AlpineApennine ophiolites derive from the Jurassic Ligurian Tethys oceanic basin formed by lithosphere extension and failure in the pre-Triassic EuropeAdria system. The basin was floored by mantle peridotites and was characterized by along-axis alternation of avolcanic and volcanic segments. Lithosphere extension and thinning caused asthenosphere adiabatic upwelling and decompressional melting. Mid-ocean ridge basalt (MORB)-type melts diffusely percolated through and reacted with the overlying lithospheric peridotites, which were strongly modified, both depleted (harzburgites and dunites) and enriched (plagioclase peridotites), by meltperidotite interaction and melt refertilization. The stratigraphicstructural features (mantle at the sea floor and alternation of avolcanic and volcanic segments) coupled with petrological features (presence of alkaline melts and strongly heterogeneous, melt-modified peridotites) allow us to interpret the Ligurian Tethys as a Jurassic analogue of modern ultraslow-spreading oceans. The Liguria Mode for the inception of an oceanic basin consists of: (1) the rifting (continental) stage, dominated by extension of continental lithosphere and tectonic exhumation of lithospheric mantle; (2) the drifting (transition) stage, characterized by melt-related processes (i.e. inception of asthenosphere partial melting and MORB melt percolation through the overlying mantle lithosphere); (3) the spreading (oceanic) stage, characterized by failure of the continental crust, sea-floor exposure of mantle peridotites and discontinuous MORB extrusion.

Description: Early during the twentieth Century, pioneering correlations between the PalaeozoicMesozoic basins of South America and southern Africa were used by Alexander du Toit to support the initial concepts of continental drift and the proposal of a united Gondwana continent. New stratigraphic tools and data can now be used to further tease out similarities and differences to reconstruct the detailed histories of these, the Parana and CapeKaroo basins. In turn this knowledge can be used also to increase our understanding of the origin and evolution of Gondwana. Recent advances in tectonics and stratigraphy showed that both basins evolved together along a common early Palaeozoic Gondwana margin facing the Panthalassa. Thereafter, this margin was transformed into a series of linked foreland basins coupled to the evolution of the Gondwanides. In detail, the foreland successions differ considerably due to spatial and temporal differences in tectonic histories along the Gondwanides. Only towards the end of the Palaeozoic did both basins evolve and merge into a single continental-scale, and truly intracratonic, terrestrial Gondwana basin that persisted until the early Cretaceous. This shared history was once again disrupted in the Early Cretaceous during the opening of the South Atlantic Ocean.

Description: The Congo (CC) and the Sao Francisco (SFC) cratons were joined at about 2.05 Ga; northern parts of Palaeoproterozoic basement subsequently underwent extension at about 1 Ga, forming intracratonic basins. Neoproterozoic metasedimentary rocks in these basins yield detrital zircons as young as 630 Ma. The Brasiliano and Pan-African (c. 620580 Ma) assembly of West Gondwana extensively altered this system. The Sergipano domain occurs north of the SFC, and the comparable Yaounde domain occurs north of the CC. Crust north of the Sergipano domain comprises the PernambucoAlagoas (PEAL) domain. The NESW-striking TchollireBanyo fault in Cameroon may extend southwestwards between the PEAL and Sergipano domains, defining northern limits of abundant SFC/CC basement. The AdamawaYade domain in Africa does not appear to extend into Brazil. The Transverse domain of Brazil is a collage of Palaeoproterozoic crustal blocks, the 1.0 Ga Cariris Velhos orogen (CVO), late Neoproterozoic basins, and Brasiliano granites. The CVO extends ENE for more than 700 km in Brazil, but eastern continuation into Africa has not been identified. North of the Transverse domain contiguous c. 2.15 Ga gneisses comprise basement of Rio Grande do Norte and Ceara domains, which continue eastwards into western Nigeria and western Sahara.

Description: Crossognathiforms have been traditionally considered typical marine Cretaceous forms widely represented in the Northern Hemisphere and by a few members in Brazil. During the last 30 years they have been interpreted as Teleostei incertae sedis, clupeocephalans or a non-monophyletic group. New evidence indicates that the Oxfordian taxon Chongichthys (previously considered a Teleostei incertae sedis or a clupeocephalan), the Late Jurassic family Varasichthyidae (interpreted as basal teleosts), and the crossognathoids and pachyrhizodontoids form a clade here recognized as the Crossognathiformes. Varasichthyids are the sister group of a clade including Chongichthys (at the base) and crossognathoids+pachyrhizodontoids. The Crossognathiformes (including Varasichthyidae and Chongichthys) are basal teleosts placed between the Late Jurassic basal genera Tharsis and Ascalabos in one tree or between Ascalabos and the ichthyodectiforms in the second tree. The position of elopomorphs as the most basal extant teleosts is confirmed. A new interpretation of the phylogenetic position of the clade [Humbertia+[Erichalcis+[Leptolepides+Orthogonikleithrum]]], at the base of clupeocephalans, is suggested. The presence of the Late Jurassic varasichthyids (e.g. Domeykos) in South America (Chile) and Central America (Cuba; Luisichthys), and Chongichthys (Chile), and of the Late Jurassic genera Ascalabos and Tharsis and the ichthyodectiforms (e.g. Allothrissops) in Europe (e.g. Germany) allows the proposal of a sister-area relationship between Chile and Cuba, which was the sister area of Germany during the Late Jurassic. The Late Jurassic connection between the Palaeopacific (Chilean region) and the Tethys Sea (southern Germany) was through the newly formed Central Atlantic Ocean (Cuban region) as a result of the break up of Pangaea and separation of North America, South America and Africa.

Description: The skeletal anatomy of fossil hiodontids from western North America is examined based on newly-prepared specimens, including several specimens that were prepared using the acid transfer method and some using the lost fossil' technique. This study resulted in many new interpretations and clarifications, such as the presence of a curved tubular nasal bone and a posterodorsal spine on the opercle of {dagger}Eohiodon', as found in extant Hiodon. We also further describe the variation of the caudal skeleton that has been known in both fossil and extant Hiodon. For instance, the neural spine of preural one is most often fully developed (as it is in a minority of extant Hiodon specimens), although in some specimens it is rudimentary, as it is in most specimens of living taxa. We review the characters that have been used in recent analyses of relationships of osteoglossomorph fishes. After correcting the descriptions of the fossil taxa, we could find no valid synapomorphies to separate the genus {dagger}Eohiodon from the genus Hiodon. Therefore, we conclude that {dagger}Eohiodon should be regarded as a synonym of Hiodon.

Description: Provenance studies on metasedimentary rocks of the Baixo Araguaia Supergroup of the Brasiliano Araguaia Belt, central Brazil, yield 207Pb/206Pb zircon evaporation ages for detrital zircons from quartzites concentrated around 10001200 Ma and 28002900 Ma; SmNd TDM model ages of schists and phyllites scatter around 16001700 Ma. Facies analysis of low-grade metasedimentary rocks from drill cores suggests a sedimentary environment of basin floor and lower- to upper-slope turbidites. Nearby sources are indicated by the textural and mineralogical immaturity; together with structural geological data indicating tectonic transport of the supracrustal pile towards the NW, this suggests probable provenance from the southeastern portion of the Araguaia Belt and not from the Amazonian Craton as usually believed. The Goias Massif, Goias Magmatic Arc, Sao Francisco Craton and Paranapanema block are considered to be the best candidates. They may have formed a larger continental mass during West Gondwana amalgamation, prior to their collision with the Amazonian Craton to form the Araguaia Belt. Final timing of this collision is constrained by c. 550 Ma syntectonic granites. Similar ages for high-grade gneisses in the Rokelide Belt suggest coeval collision and coetaneous metamorphism of the Araguaia and Rokelide belts, but more geological and geophysical data are required for a decisive correlation between these belts.

Description: Four main classes of tectonic entities may be considered for the Ribeira Belt and southwest African counterparts: (1) cratonic fragments older than 1.8 Ga and their passive margin successions, (2) reworked basement terranes with Mesoproterozoic and/or Neoproterozoic deformed cover, (3) magmatic arc associations, (4) terranes with Palaeoproterozoic basement and deformed Neoproterozoic back-arc successions. Based on comparative investigation, a tectonic model of polyphase amalgamation is proposed with c. 790 and 630610 Ma major episodes of intra-oceanic and cordilleran arc magmatism along both sides of the Adamastor Ocean. Subsequent diachronous collision of the arc terranes and small plates followed at c. 630, 600, 580 and 530 Ma. The tectonic complexity reflects an accretionary evolution from Cryogenian to Cambrian times. The Sao FranciscoCongo and Angola palaeo-continents did probably not behave as one consolidated block, but rather may have accommodated considerable convergence during the Brasiliano/Pan-African episodes. The final docking of Cabo Frio and Kalahari in the Cambrian was coeval with the arrival of Amazonia on the opposite side, resulting in lateral reactivation and displacement between the previously amalgamated pieces. The transition between the Cambrian and the Ordovician is marked by the extensional collapse of the metamorphic core zones of the orogens.

Description: Spinel lherzolites and harzburgites from Mont-Briancon and Marais de Limagne in the Deves volcanic district display coarse-grained to porphyroclastic microstructures and the modal content of volatile-bearing phases increases with the degree of deformation. Clinopyroxene and/or spinel are partly or totally reacted to amphibole. The coupled interpretations of trace-element, rare earth element (REE) and OSrNd data for clinopyroxene and amphibole indicate that the metasomatized mantle beneath Deves is a mixture of depleted and enriched mantle associated with an alkaline, high field strength element poor, and light rare earth element, U- and Th-rich carbonate-rich silicate fluidmelt metasomatic agent. Oxygen isotope and REE data for clinopyroxeneamphibole pairs indicate a (La/Yb)N enrichment related to an increasing metasomatic agent/rock ratio.

Description: A suite of mantle xenoliths from the NeogeneQuaternary volcanic province of Jabel El Arab (Syria) is dominated by spinel{+/-}amphibole harzburgites, with rare lherzolites and wehrlites that were equilibrated at temperatures of 9001100 {degrees}C. The major elements of pristine minerals and trace element compositions of clinopyroxene and amphibole indicate that the lithospheric mantle experienced various degrees of melt extraction (olivine Mg-number=89.491.8, spinel Cr-number=10.446.4), followed by a multistage metasomatic history. The primary clinopyroxene has variable and high Mg-number (89.193.6) and highly variable major element concentrations (Al2O3 2.77.6 wt%, Na2O 0.52.5 wt% and Cr2O3 0.42.5 wt%). Three groups of harzburgites were identified on the basis of petrographical, mineralogical and geochemical data. Group I harzburgites have compositions indicating a residual origin after polybaric partial melting with F 〈20%, which started in the garnet stability field and continued in the spinel stability field. Group II harzburgites are interpreted as a result of a percolation mechanism involving the infiltration of large volumes of undifferentiated basaltic melts through the residual lithosphere. Finally, the mineral major element compositions and the selectively enriched trace element contents of clinopyroxenes in group III harzburgites (high (La/Sm)N and Th, U, Sr and low high field strength element contents) are attributed to a percolation mechanism involving small volume melt fractions. Such small melt fractions correspond to CO2-bearing alkaline silicate magmas that have evolved to CO2-rich melts during repeated percolation-reaction within the Syrian lithospheric mantle. Shortly before eruption, some xenoliths were infiltrated by small silicate melt fractions, which produced discrete reaction zones composed of cpx{+/-}ol{+/-}sp{+/-}glass surrounding reacting primary spinels. The glass in the melt pockets has a trachytic to trachy-andesitic composition and its composition suggests that glass is derived from melting of pre-existing amphibole in the lithospheric mantle, triggered by infiltration of a Na-rich metasomatic agent.

Description: Chemical and isotopic compositions of amphiboles, biotites, pyroxenes and feldspars from gabbros and basalts of La Palma, Canary Islands, were studied to determine primary, plume-related compositions and effects of late-stage waterrock interactions. All the studied amphiboles have Sr isotope ratios close to those typical for the mantle, excluding the possibility of significant seawater influence. The pyroxenes and amphiboles also have stable isotope compositions that are typical for mantle-derived phases, whereas biotites and feldspars show signs of interaction with meteoric water. On the basis of the oxygen isotopic compositions, the infiltrating meteoric water derived from precipitation at an approximate elevation of 3500 m above sea level, indicating that La Palma reached this height when the gabbro complexes were formed. The unaltered hydrogen and oxygen isotope compositions of amphiboles show a trend from normal mantle ranges to 90{per thousand} and 5.1{per thousand}, respectively; these values are very close to compositions found in other Canary Island complexes by earlier studies, and support the theory that these compositions reflect a plume component originating from depth, rather than local phenomena.

Description: Neoproterozoic glacial successions have been described in South America, but the glacial deposits of the Rio de la Plata Craton have been neglected in previous studies addressing the global distribution of glacially influenced successions. The Rio de la Plata Craton contains Neoproterozoic glacial deposits in the Sierra del Volcan Formation (Tandilia System, Argentina), glacial influenced deposits in the Playa Hermosa and Zanja del Tigre formations (Dom Feliciano Belt, Uruguay) and suspected glacially influenced deposits in Passo da Areia (Sao Gabriel block, Brazil). The Tandilia System glacial record includes diamictites, dropstones and rhythmites deposited in glaciomarine conditions in a tectonically stable depositional setting. The Dom Feliciano Belt includes a thin section with ice-rafted clasts in carbonates and a thicker section containing diamictites, rhythmites, outsized clasts and deformed beds in a volcano-sedimentary succession. The Sao Gabriel block occurrence deserves more attention to confirm any glacial influence in the fine-grained part of the succession. Glaciation is considered to be contemporaneous with the Gaskiers glaciation (580 Ma), with the exception of the carbonates with dropstones that may represent a previous event correlative with one of the glaciations described in the Kalahari Craton, prior to KalahariRio de la Plata assembly in the proto-western Gondwana margin.

Description: The Eglab shield is the easternmost part of the Reguibat rise, which belongs to the West African craton (WAC). It corresponds to the amalgamation of the Yetti and Eglab Palaeoproterozoic domains. These domains are separated by a mega-shear zone called the Yetti-Eglab Junction' where fieldwork has led to the discovery of kimberlite indicator minerals but no diamond. In the southwestern part of this zone, an outcrop of Archaean basement and a komatiitic-picritic dyke had been recognized. Within the Eglab shield, deep-seated lithospheric faults control emplacement of alkaline complexes, and of small circular structures made up of mafic, ultramafic and silica-undersaturated rocks. These structural zones are characterized by widespread development of dyke swarms and repeated reactivations of earlier Eburnean trends from the Neoproterozoic to Mesozoic. Accordingly, they are sites of high magmatic permeability and crustal weakness. In this study, we summarize all known earlier and newly obtained structural, geophysical, geological and geochemical data on this area. They indicate that the Yetti-Eglab Junction' has good possibilities for the finding of kimberlite or/and other diamondiferous rocks. The features of the Eglab shield provide a possible explanation for the enigmatic sources of the diamond-bearing Reggane placer deposit located at the boundary of the WAC.