ALBERT

Description: In most hot deserts Quaternary environmental changes have left their imprint on ground conditions, creating a legacy of materials that often reflect past as well as contemporary processes, and can appear unusual to geologists trained in temperate environments. Attention is drawn in this article to three near-surface features (duricrusts, palaeolakes and sulphate-rich soils) that reflect changing environmental conditions and that are of potential significance to engineering investigation, design and construction.

Description: The results of 61 in situ UK thermal response tests, derived from three commercial test-rigs, have been analysed. Derived values of thermal conductivity yield a median of 2.25 W m K –1 , with 25th and 75th percentiles of 1.86 and 3.0 W m K –1 . The lowest single values are derived from Northern Irish basalt (1.1 W m K -1 ) and from Mesozoic and Tertiary argillites (often in the range 1.43–2 W m K –1 ), whereas the highest (〉5 W m K –1 ) are from Sherwood Sandstone and Coal Measures strata where advective heat transport with groundwater flow may have led to an elevated apparent conductivity. Borehole thermal resistance exhibits 25th percentile, median and 75th percentile values of 0.09, 0.11 and 0.14 K m W –1 and correlates with borehole heat exchanger diameter and configuration. Undisturbed ground temperature exhibits 25th percentile, median and 75th percentile values of 11.7, 12.3 and 13.2 °C and exhibits a latitude dependence.

Description: The Whitby Mudstone Formation has one of the highest landslide densities in the UK with 42 landslides per 100 km 2 . Landsliding at Hollin Hill in North Yorkshire, UK is complex and continuing, and includes shallow, retrogressive rotational failure on the upper slope, translation, and flow from the base of the Whitby Mudstone Formation over the scarp slope of the Staithes Sandstone Formation. Surface observations augmented by information relating to lithological, moisture and strength variation with depth allowed rapid initial interpretation of the masses affected by movement. These were provided by a single person operating portable probes providing depth logs of cone penetration resistance and soil moisture based upon dielectric property measurements in conjunction with a sampling auger. The gathered information was used to guide the design of further invasive site investigation and the configuration of permanent systems to monitor changes in dynamic moisture distribution and direct movement. At Hollin Hill, the near-surface materials in the upper 5 m interval are distinctly weathered or destructured, predominantly comprising silty clay in the Whitby Mudstone Formation, and fine silty, clayey sand and silty clay in the Staithes Sandstone Formation. Direct and secondary evidence was observed showing high moisture variation to be related to narrow intervals within the upper 5 m. Cyclic variation in moisture has played a key role in the movement and break-up of sliding materials, especially within the prograding lobes resulting from flow over the Staithes Sandstone Formation. Since these observations, permanent monitoring systems have been installed, including electrical resistivity tomography (ERT) arrays, which have successfully mapped the distribution of the Whitby Mudstone and the Staithes Sandstone, but will also be used in time lapse mode to image the near-surface moisture movement driving the landsliding processes. ERT array installations included a large area, low spatial resolution grid designed to investigate the potential coupling between the upper and lower slope hydrogeological processes and a small area, high spatial resolution grid designed to investigate the hydrogeological processes driving the earth flow.

Description: The thermal springs of Bath, England, produce 1.25 Ml day –1 of water at 46.5 °C. The spring at Hotwells, Bristol, England, 15 km to the west, is estimated to produce between 0.17 and 0.39 Ml day –1 of water at a temperature between 22.8 and 24.4 °C. Published research suggests that the waters originate in the Mendip Hills, SW of Bath and Bristol, and are heated by geothermal energy within the Carboniferous Limestone basin (‘The Mendips Model’). The exact paths of the waters to the springs have not been established. We interpreted seismic reflection data for the urban district of Bath and for the Radstock Basin to the south of Bath. By combining the geophysical interpretations with published geological data we have established a potential route through the Carboniferous Limestone reaching sufficient depths for the waters to attain the required temperatures. We imaged a steeply dipping, fractured region of Carboniferous Limestone coincident with the valley of the River Avon and propose that this is the feature by which the thermal waters can rise rapidly to the surface, providing an explanation for the existence of these unique springs. We have incorporated these new aspects of the Mendip Model into the ‘Mendip–Avon Fracture Zone Model’.

Description: Adverse reactions between specific aggregate particles and the pore fluids in cement pastes have been widely reported, and have been regarded as responsible for the failure of the structures into which the resulting concrete had been emplaced. The reactivity of aggregates containing various forms of silica has been well understood but similar reactions, apparently taking place between aggregates of limestone, dolostone and ‘dedolomites’, although widely recognized, remain controversial. Here we review the evidence bearing on the latter reactions and suggest a new view of their implications.

Description: Air at high pressure has recently been encountered during ground investigation borehole drilling for the Thames Tideway project in London. The air was released from within the Upnor Formation (at the base of the Lambeth Group beds), which is at the top of the Lower Aquifer. Cavitation within the granular beds of the Lower Aquifer would have occurred as a consequence of drawdown from the extensive water extraction that began at the start of the nineteenth century, resulting in the water table dropping by almost 70 m. Estimated historical pore pressure profiles are postulated and the cavitation process that occurred, along with the subsequent pressurization of the air during recharge that has occurred in recent years, are discussed using behavioural concepts from unsaturated soil mechanics. The hypotheses are corroborated by a series of simple column experiments where the processes are modelled using analogous soils. Engineering implications of the presence of the pressurized air are discussed: besides the potential for borehole blow-out, another serious consideration is the depletion of oxygen from the trapped air by chemical reaction with the soil, increasing the risk of confined space hypoxia.

Description: Predictions from laboratory tests of the compression behaviour of peat from 14 sites are compared with full-scale field loading at five sites. Data presented confirm the heterogeneous nature of the deposits. However, for typical engineering works, calculations based on laboratory test data are likely to give reasonable predictions of the magnitude of immediate and primary compression. Standard (20 mm thickness) samples may give misleading data on time for primary consolidation. Thicker samples (e.g. 50 mm) should be used. Sampling by conventional samplers, as used for mineral soils, can cause densification of the peat, resulting in underestimation of actual settlement. Block samples or sample tubes with serrated cutting edges are recommended for peat soils. It was found that the data presented follow the C α / C c law of compressibility. There is also is some evidence to suggest that the H 2 scaling law may be applicable. Good correlations were found between vertical yield stress ( p vy ') and compression index ( C c ) and index parameters such as water content ( w i ). Conventional staged construction with surcharge loading may be successfully applied to peat soils as long as adequate drainage exists to permit consolidation over reasonable time intervals.

Description: This paper discusses the interpretation of the pore water dissipation curves obtained during a piezocone test with the prime objective of determining the seismic behaviour of fine-grained soil. The pore pressure dissipation approach was attempted to perform a faster diagnosis of liquefiability of fine-grained soils where the ground water table is almost at the surface. Furthermore, because non-plastic silts are very difficult to sample for laboratory testing, such an in situ measurement appears to be the only realistic method for the purpose. Most of the dissipation tests were conducted by using the u 2 filter on the neck of the probe, and the others were performed by using the u 1 filter where the piezometer is located on the cone tip. Penetration was arrested at depths where the presence of silts had been detected by previous sounding and drilling, and t 50 , t 90 and t 100 were determined analytically. The results indicate that t 90 values have a notable potential for diagnosing a potential for liquefaction. This was demonstrated by a t 90 of 300 s or less for liquefiable layers, whereas considerably longer periods are required for non-liquefiable silts similar to clays. This feature is illustrated by the presentation of several types of dissipation curves.

Description: In the southern winter of 1970, a phreatomagmatic eruption occurred in the northern part of Deception Island (South Shetland Archipelago, Antarctic Peninsula). The eruption, with no eye-witnesses to the event, occurred in the same general area as the 1967 eruption, but with new, more widely distributed vents. Two contrasting groups of craters were formed in the 1970 eruption, showing that different active fissures and eruptive dynamics were operating. One group consists of ‘maar-like’ craters, whereas the other comprises conical edifices. The 1970 eruption can be classified as volcanic explosivity index (VEI) 3, with mainly phreatomagmatic phases that generated a bulk volume of about 0.1 km 3 of pyroclastic material and an eruptive column at least 10 km high, from which fallout deposits are recognized more than 100 km to the NE. The 1970 eruption was similar to that of 1967 and together these two eruptive events show how eruption dynamics can be controlled by the uppermost part of the volcano substrate and the width and orientation of the eruptive fissure. These influence magma–water interaction and hence may imply different eruptive phases and associated volcanic hazards. Supplementary material: Granulometric and component histograms of the samples that are not shown in Figure 4 are available at http://www.geolsoc.org.uk/SUP18761 .

Description: Neoproterozoic oceans provided the setting for the rise of animals, yet little is known of their chemical composition. Marine carbonates from the Cryogenian Oodnaminta Reef Complex, South Australia, reveal the chemical structure of a Neoproterozoic ocean. Pseudo-depth profiles from shallow- to deep-water reef facies have been constructed from geochemical and sedimentological analysis of marine cements. Evidence suggests that under a peritidal oxic–anoxic chemocline, the water column was largely anoxic, strongly ferruginous and had a chemistry profoundly different from that of modern seawater. These geochemical data suggest early Archaean-like conditions for this late Cryogenian ocean, posing problems for metazoan evolution in extremely anoxic conditions. Supplementary material: Detailed methods and data tables are available at www.geolsoc.org.uk/SUP18764 .

Description: U–Pb ages and Hf isotope data were obtained for zircon from amphibole-rich mafic to ultramafic rocks from the Adamello batholith and the Bergell pluton, the largest Palaeogene intrusions of the Alpine Orogen. The 206 Pb/ 238 U age pattern of U–Pb concordant dates from the Adamello mafic rock shows a major crystallization event at c . 41 Ma and older age peaks at c . 50 and c . 45 Ma. Hornblendite and amphibole gabbro samples of the Adamello batholith have zircon with initial Hf of c . +9.0 and c . +7.0, respectively. Amphibole gabbro and diorite samples of the Bergell pluton yield a younger age of c . 31 Ma and have zircon with lower initial Hf ( c . +4.0). We propose that the amphibole-rich rocks from the Adamello batholith originated from a depleted mantle source activated by the subduction of the Ligurian–Piedmontese Basin. The amphibole-rich rocks from the Bergell pluton formed 10–15 Ma later than the Adamello counterparts by melts derived from a mantle sector metasomatized by the subduction of the Valais Basin. The enriched Hf isotopic signature of the amphibole-rich rocks from the Bergell pluton is therefore interpreted to reflect the peculiar lithostratigraphy of the Valais Basin or a primary feature of the newly activated mantle source. Supplementary material: (1) A map showing the location of analysed samples and table with GPS coordinates of the samples, (2) data tables for U–Pb in zircon determined by LA-ICP-MS, (3) data tables for Hf isotopes in zircon, (4) U–Pb and Hf isotope analytical methods, (5) cathodoluminescence images of analysed zircon from the amphibole-rich mafic rocks of the Adamello and Bergell intrusions, and (6) a U–Pb concordia diagram for zircon of the Adamello amphibole gabbro are available at www.geolsoc.org.uk/SUP18763 .

Description: The only place where Neogene–Quaternary rocks crop out for the entire Tuscan Archipelago in the Northern Tyrrhenian Sea is the island of Pianosa. In particular, the Miocene deposits record the depositional and tectonic evolution of the Northern Tyrrhenian region during this time period. These deposits are subdivided into two successions separated by a low-angle unconformity. The older, middle Burdigalian succession represents a calciturbidite shallow marine system, whereas the younger late Tortonian–early Messinian succession comprises a continental alluvial system that evolves upwards into a lagoonal–marginal marine environment. Here we present sedimentological, palaeontological and petrographical data that support a new stratigraphic and palaeogeographical framework for reconstructing the opening of the Northern Tyrrhenian back-arc basin. The early Miocene succession records a pre-rift marine depositional phase followed by a late Burdigalian–Langhian erosional phase. This was followed by a period of synrift continental-marginal deposition, as recorded by the late Miocene succession, terminated by an important phase of uplift, probably induced by the start of magmatic activity in the Tuscan Archipelago area.

Description: Microbial carbonates contain valuable chemical, isotopic and molecular information regarding the Precambrian Earth. They record shallow-water information complementary to deep ocean proxies, such as banded iron formation and black shale. Six groups of well-preserved stromatolites illustrate how the rare earth elements (REE) are used for chemical investigation. The first task is to test whether the REE inventory of carbonate is compromised by clastic, volcanic, or diagenetic contaminants. Once the cleanliness has been verified, the shale-normalized REE pattern can be used to distinguish between marine and lacustrine settings. For marine carbonates, it is possible to distinguish between restricted basin and open marine settings and for thick platform limestones the relative water depth can be inferred from REE systematics. The studied shallow-water stromatolites range in age from 2.52 to 3.45 Ga. They contain no evidence from the behaviour of the redox-sensitive element cerium that free oxygen levels in the shallow sea approached concentrations beyond a trace gas by 2.52 Ga. Compared with abiotic early diagenetic marine carbonate cements, microbial carbonate is strongly enriched in REE. This may itself not yet serve as a biomarker, but it is regarded as a necessary prerequisite for a sample to qualify for biomarker studies.

Description: There is a basic assumption that the upper crustal point of magma emplacement overlies the point where magma was generated. This contribution discusses the concept of lateral magma movement in the upper crust based on the Mourne Granite Centres, Northern Ireland. We report anisotropy of magnetic susceptibility fabric data from the Western Mourne Centre that indicate SSW to NNE inflow in this centre, parallel to the Eastern Centre. This suggests that these two centres share a common feeder zone outside the Mourne area c. 20 km to the south, coincident with a c. 50 mGal gravity anomaly that may be caused by an unexposed mafic pluton. The links between mafic and felsic magmas in this region, and the coincidence of the projected Mourne granite feeder zone and the possible buried mafic pluton lead to a model in which the Mourne granites were emplaced in a NNE direction as two gently dipping sheets from this unexposed mafic body. From this we develop a model that incorporates existing geophysics and known tectonic framework and involves an interconnected upper crustal network of Early Palaeogene igneous intrusion pathways fed from a common tectonically controlled, and probably long-lived, deeply penetrating feeder zone.Supplementary material: Anisotropy of magnetic susceptibility data, thermomagnetic analyses and a thin section showing magnetite in biotite cleavage are available at http://www.geolsoc.org.uk/SUP18458.

Description: Combined U–Pb and Lu–Hf isotope analyses of zircons from 16 tonalite–trondjemite–granodiorite (TTG) gneiss and granite samples from Swaziland reveal that the oldest rocks of the Ancient Gneiss Complex in southern Africa formed by reworking of Early Archaean or perhaps Late Hadean crust at 3.66 Ga, and that new crust was extracted from a depleted mantle source during Palaeoarchaean events between 3.54 and 3.32 Ga. This interpretation is supported by eHft of -1.6 ± 2.0 obtained from 3.66 Ga TTG gneisses, corresponding to hafnium model ages between 3.77 ± 0.18 Ga, for a presumed Hadean–Early Archaean chondritic mantle, and 4.08 ± 0.18 Ga, for a presumed Hadean depleted mantle reservoir, with the first model age being the most likely in the light of recent data from worldwide sources. Furthermore, it is reflected by superchondritic eHft up to +2.2 ± 2.0 for TTGs formed at 3.54, 3.45 and 3.32 Ga. The new datasets additionally show that the Palaeoarchaean crust formed between 3.54 and 3.32 Ga was intensely reworked afterwards, without significant addition of depleted mantle derived material, during orogenic and intracratonic melting processes at 3.23, 3.1 and 2.7 Ga. This is well reflected by an array of decreasing eHft from +2.2 to -7.2 between 3.3 and 2.7 Ga, which can be forced by 176Lu/177Hf of 0.0113, which is similar to that of present-day average continental crust, and might result from lower crust zircon fractionation during Archaean crust reworking.Supplementary material: Results of in situ U–Pb and Lu–Hf isotope zircon analyses and concordia diagrams are available at www.geolsoc.org.uk/SUP18465.

Description: Dyke thickness datasets offer new insights into the detailed 3D geometry of dyke swarms and an exceptional opportunity to evaluate theoretical emplacement models. The Swartruggens kimberlite dyke swarm extends over 7 km along strike and intrudes a dolerite, quartzite, shale and andesitic lava succession. The Star kimberlite dykes cut shales and sandstones, intersect a large dolerite sill and extend 15 km along strike. Both dyke swarms comprise anastomosing en echelon segments, each several hundred metres long. In total 1532 Swartruggens dyke thickness measurements were taken, to 750 m below the surface over a 250 m depth range, and 3354 Star dyke thickness measurements were taken over a 520 m depth range. The Swartruggens dyke thicknesses are 0.05–1.95 m (mean 0.64 m), whereas the Star kimberlites range from

Description: The present-day Zagros mountain belt of SW Iran corresponds to the former Arabian passive continental margin of the southern Neo-Tethyan basin, which existed since a Permian–Triassic rifting episode and underwent later collisional deformation in mid- to late Cenozoic time. In West Zagros, the Kermanshah Radiolarian Trough, separated from the Neo-Tethyan basin by the narrow continental platform of the Bisotun Limestone, resulted from the Triassic–Jurassic rifting of the passive margin. Brittle tectonic analyses of syndepositional normal fault slip data have been undertaken to study the extensional history of the passive margin in terms of palaeostress reconstruction. Dominant east–west trends of the inherited rift-related normal faults in West Zagros indicate an approximately north–south trend of extension that prevailed during the entire Mesozoic syn- to post-rift evolution of the radiolarian trough. This extension characterizes a stretched continental margin similar to the present-day passive margin of the British Isles. Considering the structural pattern of the inherited basement faults, as revealed by the present-day earthquake focal mechanisms, an oblique crustal stretching model is proposed for the rifting process.

Description: Numerous structures and textures, which can be related to magma flow, were observed in felsic dykes intruding late Mesozoic granitoid plutons in the Jiaodong peninsula, in eastern Shandong province, eastern China. These flow structures may be classified into two categories, interior and peripheral. The former group includes magmatic bands, various types of folds (e.g. injection, sheath, similar and disharmonic folds), rotation of phenocrysts, magmatic foliation or lineation, and crenulation, whereas the latter includes hot tool marks and quarrying structures. Magmatic banding resulted from shearing of mingled magma during magma flow in the dykes. The magma seemed to flow rapidly, probably triggering turbulence in some thick dykes. Interaction at the contact between the hot, moving magma and the cold, stationary wallrock sometimes produced the peripheral structures. A few measurements of hot tool marks and of magmatic lineation reveal a roughly horizontal flow of magma within these dykes. For the dominant NE–SW-striking dyke set in the Laoshan granitoid pluton, the felsic magma probably ascended on or to the SW of the pluton to feed the dyke swarm, and then flowed laterally to drive the horizontal propagation of dykes.

Description: An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstätte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved temporal framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental' hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite' intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin.Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463.

Description: : In central West Greenland, Palaeogene volcanic sequences deposited during post-rift subsidence are exposed in mountains reaching 2 km above sea level (a.s.l.), with Palaeocene marine deposits within this section at elevations up to 1.2 km a.s.l. This clearly shows that present-day elevated topography of the West Greenland margin is not a remnant of the rifting process but developed later. Integrating such geological constraints with landscape analysis and thermochronological data shows that mountain summits in central West Greenland represent an Oligocene–Miocene peneplain, which is the counterpart of a correlative unconformity offshore separating Eocene from Middle Miocene sedimentary units. Onshore the peneplain has been exhumed, uplifted to its present altitude and progressively dissected since the Late Miocene. Redfield ( Journal of the Geological Society, London , 167 , 261–271, 2010) questioned numerous aspects of this interpretation, suggesting that ‘the AFT model-based hypothesis that [the elevated topography of West Greenland] was constructed in purely Neogene time remains an unproven speculation'. But as we illustrate here, evidence for Neogene uplift is provided by landscape analysis and geological evidence, as well as thermochronology, and integration of these independent lines of investigation provides a consistent synthesis that we regard as highly reliable. The resulting history of episodic burial and exhumation cannot be simply dismissed, and poses a major challenge to accepted tectonic and geomorphological models for the development of rifted continental margins: how do mountains form along passive continental margins millions of years after rifting and breakup?

Description: : The Tyrone Igneous Complex is one of the largest areas of ophiolitic and arc-related rocks exposed along the northern margin of Iapetus within the British and Irish Caledonides. New U–Pb zircon data and regional geochemistry suggest that the Tyrone Plutonic Group represents the uppermost portions of a c . 480 Ma suprasubduction-zone ophiolite accreted onto an outboard segment of Laurentia prior to 470.3 ± 1.9 Ma. The overlying Tyrone Volcanic Group formed as an island arc that collided with the Laurentian margin during the Grampian phase of the Caledonidan orogeny. Early magmatism is characterized by transitional to calc-alkaline, light REE (LREE)-enriched island-arc signatures, with an increasing component of continentally derived material up sequence. Tholeiitic rhyolites with flat to U-shaped REE profiles and LREE-depleted basalts, located stratigraphically below a c . 473 Ma rhyolite of the upper Tyrone Volcanic Group, suggest initiation of intra-arc rifting at c . 475 Ma. Metamorphic cooling ages from the Tyrone Central Inlier imply arc–continent collision before 468 ± 1.4 Ma, with the emplacement of the Tyrone Volcanic Group onto the margin. A suite of 470.3 ± 1.9 Ma to 464.3 ± 1.5 Ma calc-alkaline intrusions are associated with the continued closure of Iapetus. Supplementary material: Geochemical data and petrography are available at http://www.geolsoc.org.uk/SUP18467 .

Description: : The Nordfjord region of western Norway hosts an archetypal subducted crustal section, underpinned by ultrahigh-pressure (UHP) eclogite, overlain by Devonian sediments, and cored by a crustal-scale extensional shear zone. Structural mapping reveals two distinct displacement zones that played different roles during the formation and exhumation of this section: (1) the Sandane Shear Zone is a NW-dipping, amphibolite-facies, high-strain zone near the base of the eclogite-bearing crust that separates allochthonous units from underlying crystalline basement; it may have originated during early thrusting, but was overprinted by top-to-the-west extensional fabrics at lower crustal depths; (2) structurally above this, the Nordfjord–Sogn Detachment Zone is a top-to-the-west, amphibolite- to greenschist-facies detachment shear zone within allochthonous units that defines the upper boundary of the eclogitized crust and was responsible for exhumation through at least mid-crustal depths. Muscovite 40 Ar/ 39 Ar ages suggest that amphibolite-facies deformation below the Nordfjord–Sogn Detachment was mostly finished by c . 397 Ma, whereas muscovite ages from the deeper parts of the UHP domain indicate that it cooled after 390 Ma. During exhumation through the middle crust, west-directed stretching was accompanied by north–south folding. Late sinistral transpressional faulting in the middle to upper crust truncated the earlier folds and shear zones. Supplementary material: Complete 40 Ar/ 39 Ar data and a summary geological map of the Nordfjord region are available at http://www.geolsoc.org.uk/SUP18460 .

Description: : In this paper we present geological evidence of a mid-Cretaceous inversion event in the Polientes basin (northern Iberian plate) based on geological data. Analysis of seismic profiles across the basin indicates that this tectonic event resulted in the uplift of the basin depocentre and the formation of an upright gentle anticline before Cenomanian times. The presence of a pre-Alpine, syntectonic remagnetization in the Jurassic and Lower Cretaceous rocks of the Polientes basin allows us to define the geometry of the basin at the time between this early inversion event and the main Alpine compressional period. The early inversion in the Polientes basin is consistent with a transpressional tectonic setting, contemporaneous with the left-lateral strike-slip movement of Iberia with respect to Europe. This study shows the successful use of two approaches to unravel the geodynamic scenario of the northern Iberian plate during the Cretaceous, which was later obliterated during the Tertiary Pyrenean orogeny.

Description: : An isotope dilution thermal ionization mass spectrometry U–Pb zircon age of 411.5 ± 1.3 Ma obtained from an andesitic lava occurring within the Lower Devonian Rhynie Outlier (Aberdeenshire, NE Scotland) effectively dates the Rhynie Chert Konservat-Lagerstätte. Biostratigraphical constraints on the Rhynie Chert-bearing succession indicate that this age lies within the interval early (but not earliest) Pragian–(?)earliest Emsian. Accordingly, the Pragian–Emsian boundary must post-date or closely approximate to 411.5 ± 1.3 Ma, while the Lochkovian–Pragian boundary must predate 411.5 ± 1.3 Ma. Integration of this new high-precision age with an improved temporal framework for late Caledonian intrusive activity in NE Scotland suggests that the Rhynie hot-spring system (the ‘parental' hydrothermal system to the Rhynie cherts) was unrelated to any ‘Newer Granite' intrusion. Rhynie was instead powered by a basaltic andesite magma whose generation and ascent were directly linked to the transcurrent fault movements responsible for the formation of the Rhynie basin. Supplementary material: Details of analytical techniques (ID-TIMS U–Pb geochronology) and photomicrographs of zircon and titanite grains recovered from the Milton of Noth Andesite are available at http://www.geolsoc.org.uk/SUP18463 .

Description: : The Steptoean Positive Carbon Isotope Excursion (SPICE) of earliest late Cambrian (Furongian) age is identified in England. The excursion is found within a c . 145 m thick siliciclastic succession within the middle and higher part of the Outwoods Shale Formation of Warwickshire, and reaches a maximum 13 C org amplitude of 4.1 at values of –25.6. Biostratigraphical data show that the excursion occupies the greater part of the Olenus Biozone, an equivalent of the Glyptagnostus reticulatus Biozone that marks the base of the Furongian and coeval base of the Steptoean in North America. The amplitude of the excursion approaches that recorded in limestone-dominated Laurentian successions, and is greater than that recently documented for organic-rich mudstones of palaeocontinental Baltica in southern Sweden. A minor positive excursion above the SPICE may equate with a similar excursion recognized in Siberia. The SPICE in the Outwoods Shale Formation seems closely linked to the widely recognized early Furongian eustatic sea-level rise. There is no evidence in the English succession for slightly later regression, elsewhere considered coincident with the peak of the excursion and pivotal to some previous models explaining the SPICE. Supplementary material: Analytical results, including total organic carbon (TOC) values for each sample, are available at www.geolsoc.org.uk/SUP18455 .

Description: : The Çaldag ophiolite, in the Bornova Flysch Zone, is a fragment of Neo-Tethys in the Aegean province, western Turkey. The Bornova Flysch Zone is probably of Cretaceous age, and is locally covered by Early Eocene sediments of the Baslamis Formation that show the first evidence of exposure of ultramafic rocks. Field mapping confirms eight tectonic events correlated with the published regional history. The Çaldag ophiolite would have been exposed to weathering only from the Mid-Palaeocene to the Late Miocene and from the Mid-Pliocene until the present. This weathering has resulted in the formation of an average c . 69 m thick oxide-dominated Ni-laterite. Biological, palaeoecological and isotopic records indicate favourable conditions for weathering, comparable with those of regions in which laterites form today. These data suggest that tropical to subtropical climatic conditions dominated through most of the Cenozoic; the Palaeocene–Eocene was significantly warmer than the Oligo-Miocene. Combining the exhumation history with the available climate data better constrains the periods suitable for laterite formation with implications for laterite formation regionally. The data indicate a possible total period of 50 Ma when laterite formation was possible, yet the profile measured at Çaldag is indicative of either a shorter period of actual weathering or partial erosion of the formed profile.

Description: : There is a basic assumption that the upper crustal point of magma emplacement overlies the point where magma was generated. This contribution discusses the concept of lateral magma movement in the upper crust based on the Mourne Granite Centres, Northern Ireland. We report anisotropy of magnetic susceptibility fabric data from the Western Mourne Centre that indicate SSW to NNE inflow in this centre, parallel to the Eastern Centre. This suggests that these two centres share a common feeder zone outside the Mourne area c . 20 km to the south, coincident with a c . 50 mGal gravity anomaly that may be caused by an unexposed mafic pluton. The links between mafic and felsic magmas in this region, and the coincidence of the projected Mourne granite feeder zone and the possible buried mafic pluton lead to a model in which the Mourne granites were emplaced in a NNE direction as two gently dipping sheets from this unexposed mafic body. From this we develop a model that incorporates existing geophysics and known tectonic framework and involves an interconnected upper crustal network of Early Palaeogene igneous intrusion pathways fed from a common tectonically controlled, and probably long-lived, deeply penetrating feeder zone. Supplementary material: Anisotropy of magnetic susceptibility data, thermomagnetic analyses and a thin section showing magnetite in biotite cleavage are available at http://www.geolsoc.org.uk/SUP18458 .

Description: : Combined U–Pb and Lu–Hf isotope analyses of zircons from 16 tonalite–trondjemite–granodiorite (TTG) gneiss and granite samples from Swaziland reveal that the oldest rocks of the Ancient Gneiss Complex in southern Africa formed by reworking of Early Archaean or perhaps Late Hadean crust at 3.66 Ga, and that new crust was extracted from a depleted mantle source during Palaeoarchaean events between 3.54 and 3.32 Ga. This interpretation is supported by Hf t of –1.6 ± 2.0 obtained from 3.66 Ga TTG gneisses, corresponding to hafnium model ages between 3.77 ± 0.18 Ga, for a presumed Hadean–Early Archaean chondritic mantle, and 4.08 ± 0.18 Ga, for a presumed Hadean depleted mantle reservoir, with the first model age being the most likely in the light of recent data from worldwide sources. Furthermore, it is reflected by superchondritic Hf t up to +2.2 ± 2.0 for TTGs formed at 3.54, 3.45 and 3.32 Ga. The new datasets additionally show that the Palaeoarchaean crust formed between 3.54 and 3.32 Ga was intensely reworked afterwards, without significant addition of depleted mantle derived material, during orogenic and intracratonic melting processes at 3.23, 3.1 and 2.7 Ga. This is well reflected by an array of decreasing Hf t from +2.2 to –7.2 between 3.3 and 2.7 Ga, which can be forced by 176 Lu/ 177 Hf of 0.0113, which is similar to that of present-day average continental crust, and might result from lower crust zircon fractionation during Archaean crust reworking. Supplementary material: Results of in situ U–Pb and Lu–Hf isotope zircon analyses and concordia diagrams are available at www.geolsoc.org.uk/SUP18465 .

Description: : Numerous structures and textures, which can be related to magma flow, were observed in felsic dykes intruding late Mesozoic granitoid plutons in the Jiaodong peninsula, in eastern Shandong province, eastern China. These flow structures may be classified into two categories, interior and peripheral. The former group includes magmatic bands, various types of folds (e.g. injection, sheath, similar and disharmonic folds), rotation of phenocrysts, magmatic foliation or lineation, and crenulation, whereas the latter includes hot tool marks and quarrying structures. Magmatic banding resulted from shearing of mingled magma during magma flow in the dykes. The magma seemed to flow rapidly, probably triggering turbulence in some thick dykes. Interaction at the contact between the hot, moving magma and the cold, stationary wallrock sometimes produced the peripheral structures. A few measurements of hot tool marks and of magmatic lineation reveal a roughly horizontal flow of magma within these dykes. For the dominant NE–SW-striking dyke set in the Laoshan granitoid pluton, the felsic magma probably ascended on or to the SW of the pluton to feed the dyke swarm, and then flowed laterally to drive the horizontal propagation of dykes.

Description: : U–Pb zircon ages obtained by ion microprobe are presented for late Archaean granitoids from the Zimbabwe Craton and the North Marginal Zone of the Limpopo Belt. Similar ages of crust formation in the felsic gneisses of the Zimbabwe Craton and the felsic granulites of the North Marginal Zone support the view, previously argued on geological grounds, that they represent the middle and lower crustal layers respectively of the Zimbabwe Craton. Zircons from the southern margin of the Zimbabwe Craton and the northern part of the North Marginal Zone contain old cores, confirming the presence of an old ( c . 3.5 Ga) nucleus to the Zimbabwe Craton and indicating that the areal extent of this old nucleus is greater than has been hitherto supposed. Thus late Archaean crustal growth involved both the reworking of and the addition of new magmas to this old crustal nucleus. At 2.7 Ga crustal growth was contemporaneous with plume volcanism in the greenstone belts. In contrast, crustal growth at 2.74, 2.67, 2.64 and ?2.62 Ga was focused at the margins of the ‘old craton' and may be related to Andean style continental margin magmatism. Lower crustal melting at 2.61–2.59 Ga led to the emplacement of granitoids in the upper crust. Supplementary material: A summary of previously published U–Pb zircon geochronology for the Zimbabwe Craton and the North Marginal Zone of the Limpopo Belt, field relationships and sample localities for the samples used in this study, and U–Th–Pb secondary ionization mass spectrometry data are available at www.geolsoc.org.uk/SUP18466 .

Description: : Structural mapping, nearest neighbour and two-point azimuth statistical analysis of mud volcano vent distributions from nine examples in Azerbaijan and the Lusi mud volcano in east Java are described. Distributions are non-random, forming alignments subparallel to faults within anticlines, ring faults, conjugate faults and detachment faults; this finding confirms a spatial relationship and supports a model for subsurface flow along these features as well as showing fractionation at depth. As fracture and fault orientations are related to structures such as anticlines and the in situ stress state they are therefore predictable. We use vent distributions in Azerbaijan, where the structural geology is well constrained, to propose what controls the distribution of 169 vents at the Lusi mud volcano. This mud volcano system shows evidence for initial eruptions along a NE–SW trend, parallel to the Watukosek fault, changing to eruptions that follow east–west trends, subparallel to regional fold axes. Our analysis indicates that regions east and west of the Lusi mud volcano are more likely to be affected by new vents than those to the north and south, owing to probable onset of elongate caldera collapse within a 10 km diameter of the central vent.

Description: : The present-day Zagros mountain belt of SW Iran corresponds to the former Arabian passive continental margin of the southern Neo-Tethyan basin, which existed since a Permian–Triassic rifting episode and underwent later collisional deformation in mid- to late Cenozoic time. In West Zagros, the Kermanshah Radiolarian Trough, separated from the Neo-Tethyan basin by the narrow continental platform of the Bisotun Limestone, resulted from the Triassic–Jurassic rifting of the passive margin. Brittle tectonic analyses of syndepositional normal fault slip data have been undertaken to study the extensional history of the passive margin in terms of palaeostress reconstruction. Dominant east–west trends of the inherited rift-related normal faults in West Zagros indicate an approximately north–south trend of extension that prevailed during the entire Mesozoic syn- to post-rift evolution of the radiolarian trough. This extension characterizes a stretched continental margin similar to the present-day passive margin of the British Isles. Considering the structural pattern of the inherited basement faults, as revealed by the present-day earthquake focal mechanisms, an oblique crustal stretching model is proposed for the rifting process.

Description: : Although subduction–accretion is proposed as a major regime in making new continental crust, how the lithospheric mantle forms remains unclear. Formed after the closure of the Palaeo-Asian Ocean, the Ashele basalt shows normal mid-ocean ridge basalt (N-MORB)-like characteristics with light REE-depleted patterns and extremely low contents of high field strength elements. The low Zr/Y and Nb/Y ratios of the basalt are significantly different from those of asthenosphere-derived melts, and the excess Eu and Sr suggest that the basalt was probably derived from accreted oceanic lithospheric mantle. The presence of the N-MORB-like terrestrial basalt implies that subduction–accretion is an effective mechanism in building the refractory lithospheric mantle of Phanerozoic continents. Supplementary material: A photograph of the outcrop, and age and geochemical data are available at http://www.geolsoc.org.uk/SUP18464 .

Description: : In the British Isles the majority of volcanic rocks containing upper mantle and lower crustal xenoliths occur in Scotland. Most of the occurrences are of Carboniferous–Permian age. This paper presents new data on the mineral chemistry of spinel lherzolite xenoliths from the five principal Scottish tectonic terranes. Compositional variations among the minerals emphasize the broad lateral heterogeneity of the subcontinental lithospheric mantle across the region. The remarkable range of Al 2 O 3 v. CaO exhibited by the clinopyroxenes compared with data from other ‘xenolith provinces' emphasizes the extremely complex tectonomagmatic history of the Scottish lithosphere. The generalized age increase from southern and central Scotland to the Northern Highland and Hebridean terranes of the north and NW, with concomitant complexity of geological history, is reflected also by trace element and isotopic studies. Reaction relationships in lherzolites from the Hebridean Terrane, owing to pervasive metasomatism, involve secondary growth of sodic feldspar. This, and light REE enrichment of clinopyroxenes, points to involvement of a natro-carbonatitic melt. Most pyroxenitic xenoliths are inferred to form a basal crustal layer with a generally sharp discontinuity above the underlying (dominantly lherzolitic) mantle. A second discontinuity is inferred to separate these ultramafic cumulates from overlying, broadly cognate metagabbroic cumulates.

Description: : Dyke thickness datasets offer new insights into the detailed 3D geometry of dyke swarms and an exceptional opportunity to evaluate theoretical emplacement models. The Swartruggens kimberlite dyke swarm extends over 7 km along strike and intrudes a dolerite, quartzite, shale and andesitic lava succession. The Star kimberlite dykes cut shales and sandstones, intersect a large dolerite sill and extend 15 km along strike. Both dyke swarms comprise anastomosing en echelon segments, each several hundred metres long. In total 1532 Swartruggens dyke thickness measurements were taken, to 750 m below the surface over a 250 m depth range, and 3354 Star dyke thickness measurements were taken over a 520 m depth range. The Swartruggens dyke thicknesses are 0.05–1.95 m (mean 0.64 m), whereas the Star kimberlites range from 〈0.01 to 1.6 m thick (mean 0.40 m). Two-dimensional models of elastic cracks in a homogeneous, isotropic material subject to constant magmatic over-pressure poorly describe the dyke thickness variation, which is complex and varies along both breadth and length. The Swartruggens dyke segments thicken toward their terminations along strike, which represent regions where stresses were focused. Towards the surface, rock deformation is increasingly difficult to recover as inelastic processes such as host-rock brecciation, stoping, and magma solidification become important.

Description: : The Andaman ophiolite occurs as thrust slices in the outer arc of the Andaman–Java subduction zone. This ophiolite preserves the mantle sequence, layered ultramafic–mafic rocks, intrusive and extrusive rocks. The mantle sequence is represented by serpentinized lherzolite and harzburgite, hosting dunite and chromitite pods. The low Cr-number (0.2–0.4), Cr-number–TiO 2 relation of the chromites, oxygen fugacity ( f O 2 ) values ( log f O 2 (FMQ) = –1.90) and trace elements of mantle peridotites indicate a mid-ocean ridge basalt–suprasubduction-zone (MORB–SSZ) setting. The MORB mantle underwent a low degree of melting ( c . 10–15%) and interacted with the subduction-zone melts. Melt–rock interaction of the peridotites in a suprasubduction zone is demonstrated by the replacement of pyroxene grains by olivine grains (Fo 90 ), composition of chromites and oxygen fugacity ( log f O 2 (FMQ) = –1.90 to +2.16, where FMQ is the fayalite–magnetite–quartz buffer). The chromite composition of chromitite pods (Cr-number 0.72–0.75), f O 2 levels and trace elements for layered peridotites, and occurrence of the extrusive rocks as low-Ca boninite and island arc tholeiitic (IAT) basalt indicate interplay of both boninite and IAT melts for the Andaman ophiolite. The MORB mantle of the subducting Indian plate accreted into the mantle wedge and then melting of the accreted mantle produced boninite melt at the first stage and tholeiitic melts at the second stage. Supplementary material: Sample co-ordinates from the Andaman ophiolite, mineral analysis data for all the samples, modal compositions of the units of the Andaman ophiolite and details of the laboratory analyses including details of the standard are available at http://www.geolsoc.org.uk/SUP18459 .

Description: : The Late Neogene and Quaternary sedimentary record within the Maltese islands is very fragmentary and has generally been ignored by sedimentologists. Local stratigraphies for parts of the Quaternary have been erected from vertebrate remains contained in Quaternary cave and fissure deposits of the islands. However, no coherent correlation scheme has been proposed in which to encompass them. The situation is exacerbated by the absence of datable fossils within the majority of Quaternary deposits. Considerable progress in resolving these problems is, however, possible if recourse is made to the post-Messinian (Late Miocene) erosion features evidenced in the topography of the islands. In particular, a hitherto unrecognized marine erosion surface, the San Leonardo Marine Abrasion Surface, is described and dated by reference to the marine deposits (San Leonardo Beds) lying directly above it and similarities to contemporaneous SE Sicily marine deposits. This provides an end-Calabrian Stage (Emilian Sub-Stage) base line upon which to hang fragmentary information on later events that have shaped the topography of the Maltese islands. From this it can be confirmed that a tectonic deformation event spanning latest Messinian to mid- Pliocene times uplifted the islands and reactivated previously incipient graben systems. This deformation episode is shown to have ceased within the islands well before the early Calabrian (before c . 1.6 Ma). Subsequent minor regional uplift and eustacy together with subaerial weathering processes have been the principal agents in shaping the islands. Collectively, these processes have prevented terrestrial animal migrations into the Maltese islands from North Africa since Messinian times. However, the infrequent re-establishment of a marine lowstand isthmus virtually linking Malta with SE Sicily has permitted opportunistic animal migrations into the islands and the presence of these greatly aids in dating the sedimentological events.

Description: : The Early Palaeozoic stratigraphy and tectonic history of the Eastern Sierras Pampeanas of central Argentina are complicated by metamorphism and deformation resulting from the Pampean (545–510 Ma) and Famatinian (490–440 Ma) orogenies. We report U–Pb sensitive high-resolution ion microprobe dating of detrital zircons in two metasedimentary successions exposed at Quebrada de La Cébila ( c . 28°45'S, 66°25'W): the Ambato and the La Cébila metamorphic complexes. The Ambato zircons record age peaks corresponding to Pampean (530 ± 10 Ma), Brasiliano ( c . 570 and c . 640 Ma), Grenville ( c . 950 to c . 1025 Ma) and minor Neoarchaean ages. Similar peaks are also apparent in the La Cébila sample but it additionally contains Palaeoproterozoic zircons ( c . 2.1 Ga) corresponding to the age of the Rio de la Plata craton, from which they are considered to have been sourced. Our interpretation is that the protolith of the Ambato complex was deposited prior to juxtaposition with the craton and is older than the Early Ordovician La Cébila metamorphic complex. We infer that the craton reached its current relative position in the Mid- to Late Cambrian, after the main Pampean tectonothermal event (530–520 Ma) and before deposition of the La Cébila protolith and the Achavil Formation (Sierra de Famatina), which contain comparable detrital zircon populations.

Description: : Major fluvial incision (600–1000 m) affecting the Coastal Cordillera and Central Depression of northern Chile is analysed to evaluate supposed coeval uplift of the Altiplano and/or climatic changes in the Atacama Desert. The timing of the beginning of incision is constrained by the age of deposition of the Central Depression top. In the north (18–19°S), this top corresponds to fluvial gravels accumulated between 11.9 ± 0.6 Ma and 8.3 ± 0.5 Ma, which are genetically related to semiarid climate and to an eastward poorly dissected parallel drainage network that developed between 15.0 ± 0.6 and 11.2 ± 0.6 Ma; thus, gravel deposition ended at 11.9–11.2 Ma. To the south (19–20°S), the Central Depression top corresponds to c . 6 Ma alluvial deposits. Stratigraphically determined canyon ages and knickzone locations indicate that southward dissection began later and/or developed under a regime of lower erosion capacity owing to drier climate. Vertical incision rate evolution is compatible with eastward knickzone migration. Dissection required a considerable altitude difference between ancient and present-day river base levels, which was achieved predominantly by basin infill on an already partially elevated bedrock. Therefore subsequent incision would have been triggered by local semiarid climatic periods rather than by contemporaneous surface uplift. Exoreic canyons occur when climatic conditions in the catchments are arid–semiarid whereas endoreism is developed when these conditions in catchments are hyperarid.

Description: In central West Greenland, Palaeogene volcanic sequences deposited during post-rift subsidence are exposed in mountains reaching 2 km above sea level (a.s.l.), with Palaeocene marine deposits within this section at elevations up to 1.2 km a.s.l. This clearly shows that present-day elevated topography of the West Greenland margin is not a remnant of the rifting process but developed later. Integrating such geological constraints with landscape analysis and thermochronological data shows that mountain summits in central West Greenland represent an Oligocene–Miocene peneplain, which is the counterpart of a correlative unconformity offshore separating Eocene from Middle Miocene sedimentary units. Onshore the peneplain has been exhumed, uplifted to its present altitude and progressively dissected since the Late Miocene. Redfield (Journal of the Geological Society, London, 167, 261–271, 2010) questioned numerous aspects of this interpretation, suggesting that ‘the AFT model-based hypothesis that [the elevated topography of West Greenland] was constructed in purely Neogene time remains an unproven speculation'. But as we illustrate here, evidence for Neogene uplift is provided by landscape analysis and geological evidence, as well as thermochronology, and integration of these independent lines of investigation provides a consistent synthesis that we regard as highly reliable. The resulting history of episodic burial and exhumation cannot be simply dismissed, and poses a major challenge to accepted tectonic and geomorphological models for the development of rifted continental margins: how do mountains form along passive continental margins millions of years after rifting and breakup?

Description: The Tyrone Igneous Complex is one of the largest areas of ophiolitic and arc-related rocks exposed along the northern margin of Iapetus within the British and Irish Caledonides. New U–Pb zircon data and regional geochemistry suggest that the Tyrone Plutonic Group represents the uppermost portions of a c. 480 Ma suprasubduction-zone ophiolite accreted onto an outboard segment of Laurentia prior to 470.3 ± 1.9 Ma. The overlying Tyrone Volcanic Group formed as an island arc that collided with the Laurentian margin during the Grampian phase of the Caledonidan orogeny. Early magmatism is characterized by transitional to calc-alkaline, light REE (LREE)-enriched island-arc signatures, with an increasing component of continentally derived material up sequence. Tholeiitic rhyolites with flat to U-shaped REE profiles and LREE-depleted basalts, located stratigraphically below a c. 473 Ma rhyolite of the upper Tyrone Volcanic Group, suggest initiation of intra-arc rifting at c. 475 Ma. Metamorphic cooling ages from the Tyrone Central Inlier imply arc–continent collision before 468 ± 1.4 Ma, with the emplacement of the Tyrone Volcanic Group onto the margin. A suite of 470.3 ± 1.9 Ma to 464.3 ± 1.5 Ma calc-alkaline intrusions are associated with the continued closure of Iapetus.Supplementary material: Geochemical data and petrography are available at http://www.geolsoc.org.uk/SUP18467.

Description: U–Pb zircon ages obtained by ion microprobe are presented for late Archaean granitoids from the Zimbabwe Craton and the North Marginal Zone of the Limpopo Belt. Similar ages of crust formation in the felsic gneisses of the Zimbabwe Craton and the felsic granulites of the North Marginal Zone support the view, previously argued on geological grounds, that they represent the middle and lower crustal layers respectively of the Zimbabwe Craton. Zircons from the southern margin of the Zimbabwe Craton and the northern part of the North Marginal Zone contain old cores, confirming the presence of an old (c. 3.5 Ga) nucleus to the Zimbabwe Craton and indicating that the areal extent of this old nucleus is greater than has been hitherto supposed. Thus late Archaean crustal growth involved both the reworking of and the addition of new magmas to this old crustal nucleus. At 2.7 Ga crustal growth was contemporaneous with plume volcanism in the greenstone belts. In contrast, crustal growth at 2.74, 2.67, 2.64 and ?2.62 Ga was focused at the margins of the ‘old craton' and may be related to Andean style continental margin magmatism. Lower crustal melting at 2.61–2.59 Ga led to the emplacement of granitoids in the upper crust.Supplementary material: A summary of previously published U–Pb zircon geochronology for the Zimbabwe Craton and the North Marginal Zone of the Limpopo Belt, field relationships and sample localities for the samples used in this study, and U–Th–Pb secondary ionization mass spectrometry data are available at www.geolsoc.org.uk/SUP18466.

Description: Structural mapping, nearest neighbour and two-point azimuth statistical analysis of mud volcano vent distributions from nine examples in Azerbaijan and the Lusi mud volcano in east Java are described. Distributions are non-random, forming alignments subparallel to faults within anticlines, ring faults, conjugate faults and detachment faults; this finding confirms a spatial relationship and supports a model for subsurface flow along these features as well as showing fractionation at depth. As fracture and fault orientations are related to structures such as anticlines and the in situ stress state they are therefore predictable. We use vent distributions in Azerbaijan, where the structural geology is well constrained, to propose what controls the distribution of 169 vents at the Lusi mud volcano. This mud volcano system shows evidence for initial eruptions along a NE–SW trend, parallel to the Watukosek fault, changing to eruptions that follow east–west trends, subparallel to regional fold axes. Our analysis indicates that regions east and west of the Lusi mud volcano are more likely to be affected by new vents than those to the north and south, owing to probable onset of elongate caldera collapse within a 10 km diameter of the central vent.

Description: In the British Isles the majority of volcanic rocks containing upper mantle and lower crustal xenoliths occur in Scotland. Most of the occurrences are of Carboniferous–Permian age. This paper presents new data on the mineral chemistry of spinel lherzolite xenoliths from the five principal Scottish tectonic terranes. Compositional variations among the minerals emphasize the broad lateral heterogeneity of the subcontinental lithospheric mantle across the region. The remarkable range of Al2O3 v. CaO exhibited by the clinopyroxenes compared with data from other ‘xenolith provinces' emphasizes the extremely complex tectonomagmatic history of the Scottish lithosphere. The generalized age increase from southern and central Scotland to the Northern Highland and Hebridean terranes of the north and NW, with concomitant complexity of geological history, is reflected also by trace element and isotopic studies. Reaction relationships in lherzolites from the Hebridean Terrane, owing to pervasive metasomatism, involve secondary growth of sodic feldspar. This, and light REE enrichment of clinopyroxenes, points to involvement of a natro-carbonatitic melt. Most pyroxenitic xenoliths are inferred to form a basal crustal layer with a generally sharp discontinuity above the underlying (dominantly lherzolitic) mantle. A second discontinuity is inferred to separate these ultramafic cumulates from overlying, broadly cognate metagabbroic cumulates.

Description: In this paper we present geological evidence of a mid-Cretaceous inversion event in the Polientes basin (northern Iberian plate) based on geological data. Analysis of seismic profiles across the basin indicates that this tectonic event resulted in the uplift of the basin depocentre and the formation of an upright gentle anticline before Cenomanian times. The presence of a pre-Alpine, syntectonic remagnetization in the Jurassic and Lower Cretaceous rocks of the Polientes basin allows us to define the geometry of the basin at the time between this early inversion event and the main Alpine compressional period. The early inversion in the Polientes basin is consistent with a transpressional tectonic setting, contemporaneous with the left-lateral strike-slip movement of Iberia with respect to Europe. This study shows the successful use of two approaches to unravel the geodynamic scenario of the northern Iberian plate during the Cretaceous, which was later obliterated during the Tertiary Pyrenean orogeny.

Description: The Andaman ophiolite occurs as thrust slices in the outer arc of the Andaman–Java subduction zone. This ophiolite preserves the mantle sequence, layered ultramafic–mafic rocks, intrusive and extrusive rocks. The mantle sequence is represented by serpentinized lherzolite and harzburgite, hosting dunite and chromitite pods. The low Cr-number (0.2–0.4), Cr-number–TiO2 relation of the chromites, oxygen fugacity (fO2) values (?log fO2 (FMQ) = -1.90) and trace elements of mantle peridotites indicate a mid-ocean ridge basalt–suprasubduction-zone (MORB–SSZ) setting. The MORB mantle underwent a low degree of melting (c. 10–15%) and interacted with the subduction-zone melts. Melt–rock interaction of the peridotites in a suprasubduction zone is demonstrated by the replacement of pyroxene grains by olivine grains (Fo90), composition of chromites and oxygen fugacity (?log fO2 (FMQ) = –1.90 to +2.16, where FMQ is the fayalite–magnetite–quartz buffer). The chromite composition of chromitite pods (Cr-number 0.72–0.75), fO2 levels and trace elements for layered peridotites, and occurrence of the extrusive rocks as low-Ca boninite and island arc tholeiitic (IAT) basalt indicate interplay of both boninite and IAT melts for the Andaman ophiolite. The MORB mantle of the subducting Indian plate accreted into the mantle wedge and then melting of the accreted mantle produced boninite melt at the first stage and tholeiitic melts at the second stage.Supplementary material: Sample co-ordinates from the Andaman ophiolite, mineral analysis data for all the samples, modal compositions of the units of the Andaman ophiolite and details of the laboratory analyses including details of the standard are available at http://www.geolsoc.org.uk/SUP18459.

Description: The Çaldag ophiolite, in the Bornova Flysch Zone, is a fragment of Neo-Tethys in the Aegean province, western Turkey. The Bornova Flysch Zone is probably of Cretaceous age, and is locally covered by Early Eocene sediments of the Baslamis Formation that show the first evidence of exposure of ultramafic rocks. Field mapping confirms eight tectonic events correlated with the published regional history. The Çaldag ophiolite would have been exposed to weathering only from the Mid-Palaeocene to the Late Miocene and from the Mid-Pliocene until the present. This weathering has resulted in the formation of an average c. 69 m thick oxide-dominated Ni-laterite. Biological, palaeoecological and isotopic records indicate favourable conditions for weathering, comparable with those of regions in which laterites form today. These data suggest that tropical to subtropical climatic conditions dominated through most of the Cenozoic; the Palaeocene–Eocene was significantly warmer than the Oligo-Miocene. Combining the exhumation history with the available climate data better constrains the periods suitable for laterite formation with implications for laterite formation regionally. The data indicate a possible total period of 50 Ma when laterite formation was possible, yet the profile measured at Çaldag is indicative of either a shorter period of actual weathering or partial erosion of the formed profile.

Description: The Early Palaeozoic stratigraphy and tectonic history of the Eastern Sierras Pampeanas of central Argentina are complicated by metamorphism and deformation resulting from the Pampean (545–510 Ma) and Famatinian (490–440 Ma) orogenies. We report U–Pb sensitive high-resolution ion microprobe dating of detrital zircons in two metasedimentary successions exposed at Quebrada de La Cébila (c. 28°45'S, 66°25'W): the Ambato and the La Cébila metamorphic complexes. The Ambato zircons record age peaks corresponding to Pampean (530 ± 10 Ma), Brasiliano (c. 570 and c. 640 Ma), Grenville (c. 950 to c. 1025 Ma) and minor Neoarchaean ages. Similar peaks are also apparent in the La Cébila sample but it additionally contains Palaeoproterozoic zircons (c. 2.1 Ga) corresponding to the age of the Rio de la Plata craton, from which they are considered to have been sourced. Our interpretation is that the protolith of the Ambato complex was deposited prior to juxtaposition with the craton and is older than the Early Ordovician La Cébila metamorphic complex. We infer that the craton reached its current relative position in the Mid- to Late Cambrian, after the main Pampean tectonothermal event (530–520 Ma) and before deposition of the La Cébila protolith and the Achavil Formation (Sierra de Famatina), which contain comparable detrital zircon populations.

Description: Although subduction–accretion is proposed as a major regime in making new continental crust, how the lithospheric mantle forms remains unclear. Formed after the closure of the Palaeo-Asian Ocean, the Ashele basalt shows normal mid-ocean ridge basalt (N-MORB)-like characteristics with light REE-depleted patterns and extremely low contents of high field strength elements. The low Zr/Y and Nb/Y ratios of the basalt are significantly different from those of asthenosphere-derived melts, and the excess Eu and Sr suggest that the basalt was probably derived from accreted oceanic lithospheric mantle. The presence of the N-MORB-like terrestrial basalt implies that subduction–accretion is an effective mechanism in building the refractory lithospheric mantle of Phanerozoic continents.Supplementary material: A photograph of the outcrop, and age and geochemical data are available at http://www.geolsoc.org.uk/SUP18464.

Description: Major fluvial incision (600–1000 m) affecting the Coastal Cordillera and Central Depression of northern Chile is analysed to evaluate supposed coeval uplift of the Altiplano and/or climatic changes in the Atacama Desert. The timing of the beginning of incision is constrained by the age of deposition of the Central Depression top. In the north (18–19°S), this top corresponds to fluvial gravels accumulated between 11.9 ± 0.6 Ma and 8.3 ± 0.5 Ma, which are genetically related to semiarid climate and to an eastward poorly dissected parallel drainage network that developed between 15.0 ± 0.6 and 11.2 ± 0.6 Ma; thus, gravel deposition ended at 11.9–11.2 Ma. To the south (19–20°S), the Central Depression top corresponds to c. 6 Ma alluvial deposits. Stratigraphically determined canyon ages and knickzone locations indicate that southward dissection began later and/or developed under a regime of lower erosion capacity owing to drier climate. Vertical incision rate evolution is compatible with eastward knickzone migration. Dissection required a considerable altitude difference between ancient and present-day river base levels, which was achieved predominantly by basin infill on an already partially elevated bedrock. Therefore subsequent incision would have been triggered by local semiarid climatic periods rather than by contemporaneous surface uplift. Exoreic canyons occur when climatic conditions in the catchments are arid–semiarid whereas endoreism is developed when these conditions in catchments are hyperarid.

Description: The Nordfjord region of western Norway hosts an archetypal subducted crustal section, underpinned by ultrahigh-pressure (UHP) eclogite, overlain by Devonian sediments, and cored by a crustal-scale extensional shear zone. Structural mapping reveals two distinct displacement zones that played different roles during the formation and exhumation of this section: (1) the Sandane Shear Zone is a NW-dipping, amphibolite-facies, high-strain zone near the base of the eclogite-bearing crust that separates allochthonous units from underlying crystalline basement; it may have originated during early thrusting, but was overprinted by top-to-the-west extensional fabrics at lower crustal depths; (2) structurally above this, the Nordfjord–Sogn Detachment Zone is a top-to-the-west, amphibolite- to greenschist-facies detachment shear zone within allochthonous units that defines the upper boundary of the eclogitized crust and was responsible for exhumation through at least mid-crustal depths. Muscovite 40Ar/39Ar ages suggest that amphibolite-facies deformation below the Nordfjord–Sogn Detachment was mostly finished by c. 397 Ma, whereas muscovite ages from the deeper parts of the UHP domain indicate that it cooled after 390 Ma. During exhumation through the middle crust, west-directed stretching was accompanied by north–south folding. Late sinistral transpressional faulting in the middle to upper crust truncated the earlier folds and shear zones.Supplementary material: Complete 40Ar/39Ar data and a summary geological map of the Nordfjord region are available at http://www.geolsoc.org.uk/SUP18460.

Description: The Steptoean Positive Carbon Isotope Excursion (SPICE) of earliest late Cambrian (Furongian) age is identified in England. The excursion is found within a c. 145 m thick siliciclastic succession within the middle and higher part of the Outwoods Shale Formation of Warwickshire, and reaches a maximum d13Corg amplitude of 4.1‰ at values of -25.6‰. Biostratigraphical data show that the excursion occupies the greater part of the Olenus Biozone, an equivalent of the Glyptagnostus reticulatus Biozone that marks the base of the Furongian and coeval base of the Steptoean in North America. The amplitude of the excursion approaches that recorded in limestone-dominated Laurentian successions, and is greater than that recently documented for organic-rich mudstones of palaeocontinental Baltica in southern Sweden. A minor positive excursion above the SPICE may equate with a similar excursion recognized in Siberia. The SPICE in the Outwoods Shale Formation seems closely linked to the widely recognized early Furongian eustatic sea-level rise. There is no evidence in the English succession for slightly later regression, elsewhere considered coincident with the peak of the excursion and pivotal to some previous models explaining the SPICE.Supplementary material: Analytical results, including total organic carbon (TOC) values for each sample, are available at www.geolsoc.org.uk/SUP18455.

Description: The Late Neogene and Quaternary sedimentary record within the Maltese islands is very fragmentary and has generally been ignored by sedimentologists. Local stratigraphies for parts of the Quaternary have been erected from vertebrate remains contained in Quaternary cave and fissure deposits of the islands. However, no coherent correlation scheme has been proposed in which to encompass them. The situation is exacerbated by the absence of datable fossils within the majority of Quaternary deposits. Considerable progress in resolving these problems is, however, possible if recourse is made to the post-Messinian (Late Miocene) erosion features evidenced in the topography of the islands. In particular, a hitherto unrecognized marine erosion surface, the San Leonardo Marine Abrasion Surface, is described and dated by reference to the marine deposits (San Leonardo Beds) lying directly above it and similarities to contemporaneous SE Sicily marine deposits. This provides an end-Calabrian Stage (Emilian Sub-Stage) base line upon which to hang fragmentary information on later events that have shaped the topography of the Maltese islands. From this it can be confirmed that a tectonic deformation event spanning latest Messinian to mid- Pliocene times uplifted the islands and reactivated previously incipient graben systems. This deformation episode is shown to have ceased within the islands well before the early Calabrian (before c. 1.6 Ma). Subsequent minor regional uplift and eustacy together with subaerial weathering processes have been the principal agents in shaping the islands. Collectively, these processes have prevented terrestrial animal migrations into the Maltese islands from North Africa since Messinian times. However, the infrequent re-establishment of a marine lowstand isthmus virtually linking Malta with SE Sicily has permitted opportunistic animal migrations into the islands and the presence of these greatly aids in dating the sedimentological events.

Description: The key problem addressed in this paper arises in the situation where multi-scale shale drapes are present along channel, channel-belt and/or valley-bounding surfaces, but the channel location is uncertain or unknown. In order to reduce this uncertainty, the channel and drape locations should be modified in order to calibrate the flow response to the historic production data as well as any static data from wells. We propose a coupled geological modelling and history-matching method in which the reservoir architecture composed of channels is simulated with a pre-defined stacking pattern, then the shale drapes are simulated along the bounding surfaces using a multiple-point statistics technique and, finally, channel and scour-hole locations are gradually perturbed until the corresponding flow responses match the field production data. The perturbation during the history matching must be geologically consistent, i.e. the result must honour the observed individual channel geometries and the interpreted channel stacking patterns. A digital 3D model representing a real field in offshore West Africa was studied to demonstrate this modelling and history-matching approach in which the multi-scale shale drapes are simulated and perturbed while the reservoir geological concepts are preserved and the well data are honoured. The final history-matched geological models have better prediction power than geological models built with randomly selected input parameters.

Description: In this study, all available geological, geophysical and geochemical data were integrated to assess the hydrocarbon prospectivity of the Haymana Basin, an interior basin in Central Anatolia. First, the basin was modelled in three dimensions (3D) using gravity data which identified the deepest part of the basin to the east of Haymana, south of Ankara. This potential hydrocarbon generation area has not been properly explored. Next, the first order vertical derivative of the gravity anomaly map was computed to identify boundaries of prospective structures from inflections in the gravity gradient. Aeromagnetic data were transformed to an analytical signal to identify the probable locations of buried magmatic intrusions. The prospective part of the Haymana Basin was interpreted as being located to the east of an intrusion. Finally, all available geochemical data of the Kirkkavak Formation were classified for different parameters (TOC, S1+S2 and Tmax) and maximum values of each parameter were mapped. In comparing the 3D depth model with individual geochemical maps, it was observed that each geochemical parameter was consistent with the interpreted prospective zone of the Haymana Basin.

Description: A comprehensive simulation study tested and analysed the sensitivity of dynamic connectivity in turbidite channel reservoirs to a large number of stratigraphic and engineering parameters. The study showed that subseismic shale architecture has a significant effect on reservoir connectivity. However, representing the complete spectrum of fine-scale architectural details in full-field simulation models is beyond the limits of existing computational capabilities. Previous work demonstrated that incorporating geologically based pseudo-relative permeabilities into relatively coarse full-field reservoir models renders practically intractable simulation cases tractable. We developed a methodology for generating pseudo-relative permeabilities at multiple geological scales, incorporating the effect of channel architecture and reservoir connectivity into fast simulation models. We describe a dynamic modelling workflow that integrates geologically based pseudo-relative permeabilities into a two-stage automatic history-matching algorithm. The history-matching problem is posed as one of data conditioning in the Bayesian framework. We show the application of the workflow to a channelized turbidite reservoir in West Africa. It is demonstrated that multiple geologically consistent models that are conditioned to production data can be generated rapidly thanks to optimally coarse simulation models that capture the effect of subseismic channel architecture on recovery behaviour, and run efficiently as the forward model within a Bayesian inference framework. Proof-of-concept tests carried out using field data indicate that the history-matched models predict well-by-well future recovery response with good accuracy.

Description: This paper provides data on the lateral continuity and geometry of potential reservoir geobodies in outcrops of Upper Khuff Formation time-equivalent strata in the Jebel Al Akhdar area (Oman Mountains, Sultanate of Oman). It presents outcrop-based quantitative data of shoal-associated grainstone bodies in a sequence stratigraphic framework on the scale of an average Khuff gas field. Such data may be useful for correlation and modelling of subsurface reservoirs. A stratigraphic correlation of five outcrop sections, based on facies, sequence analysis and gamma-ray pattern, was used as a framework for mapping the distribution and lateral extent of grainstone geobodies over an area of 8 x 8 km. Four grainstone bodies were traced laterally along distinct marker beds over several hundreds of metres. The stratigraphic architecture shows a general layer-cake pattern. The thickness and lateral extent of reservoir geobodies is strongly influenced by their stratigraphic position. High-energy shoal facies developed preferentially in the regressive parts of cycles of multiple hierarchies. Individual grainstone bodies may reach a thickness of 6 m, and those thicker than 3 m extend across the area of interest. Clinoforms or shingle-type geometries were explicitly searched for, but were not present. The observed systematic variations in extent and two-dimensional sedimentary architecture of Khuff grainstone bodies were used as input for 3D static facies modelling. Outcomes of this study have been used to reduce uncertainty on grainstone geometries, production-scale correlation strategies and definition of lateral facies successions in subsurface models of the Khuff reservoir.

Description: A detailed interpretation of seismic data has been carried out to analyse salt diapirism in the Straits of Hormuz in the Persian Gulf. Salt diapirs in the Zagros Foldbelt are mainly characterized by structures formed by mobilization of the Cambrian Hormuz salt as reactive diapirs during the Late Cretaceous-Tertiary Zagros orogeny. Interpretation of available data in the straits of Hormuz suggests that diapirs of Hormuz salt grew actively until the Early Miocene and then continued to rise passively by downbuilding of surrounding sediments until the present time. The syn- to post-Miocene Zagros sedimentation played a major role in passive diapirism. Sedimentation of the thick Lower Miocene deposits led to greater subsidence of the basin and passive diapirism of the Early Miocene Fars salt as well as further inflation of the Hormuz salt into neighbouring structures. Seismic mapping of the salt-related structures as well as observations in the overlying sediments, such as thickness variations and faulting, also constrain the Late Tertiary passive diapirism of the Hormuz and Fars salt in the Zagros.

Description: Nuclear magnetic resonance (NMR) is a useful tool in reservoir evaluation. The objective of this study is to predict petrophysical properties from NMR T2 distributions. A series of laboratory experiments including core analysis, capillary pressure measurements, NMR T2 measurements and image analysis were carried out on sixteen greensand samples from two formations in the Nini field of the North Sea. Hermod Formation is weakly cemented, whereas Ty Formation is characterized by microcrystalline quartz cement. The surface area measured by the BET method and the NMR derived surface relaxivity are associated with the micro-porous glauconite grains. The effective specific surface area as calculated from Kozeny's equation and as derived from petrographic image analysis of backscattered electron micrograph's (BSE), as well as the estimated effective surface relaxivity, is associated with macro-pores. Permeability may be predicted from NMR by using Kozeny's equation when surface relaxivity is known. Capillary pressure drainage curves may be predicted from NMR T2 distribution when pore size distribution within a sample is homogeneous.

Description: This paper presents an integrated seismic, petrophysical and analogue core study of the Mid-Eocene Grid deep-water Sandstone Member from the Nelson Field area, Central North Sea. Two possible turbiditic units were identified in seismic data. Grid 1 shows channel-like features and a complex stratigraphy whilst Grid 2 consists of scattered bright amplitude events (shown to be slumped shales and chalky limestones by cuttings analysis). Lower Eocene Tay Sandstone Member core from the nearby Gannet Field provided an analogue for sedimentary facies. This enabled petrophysical and seismic observations of the Grid Sandstone Member to be tied to sedimentological facies. An integrated model shows five facies associations and a complex reservoir quality distribution. A comparison with outcrop and seismic examples of channelized turbidites indicates that the Grid system represents a medium-scale channel complex, exhibiting multi-storey, nested offset stacking. This work presents a new example that provides a link between laboratory experiments on topographic interaction of turbidite flows with seismic-scale observations and facies determination. The Grid system also adds to our knowledge of Palaeogene turbidite evolution from sheet-like to channel-like forms and provides a useful analogue for improving hydrocarbon exploration and production efficiency in adjacent areas.

Description: Reservoir mapping in the Gulf of Suez petroleum system is challenging because rift-parallel and cross-rift faults disrupted the sediments, leaving the reservoirs confined to stratigraphic, structural, and combined traps. We have developed a technique to address this challenge that integrates fault outcrop mapping using satellite image interpretation, seismic near-surface characterization techniques such as Rayleigh wave velocity mapping and ray parameter interferometry, as well as ant tracking of faults and geobody delineation on a prestack time-migrated (PSTM) cube. The technique uses a combination of geographic information system (GIS) and geological modelling software such as Petrel for surface/subsurface integration. The joint analysis of Rayleigh wave data with satellite imagery provides a near-surface structural geological model. The acquisition, processing, and interpretation of point-receiver seismic data enables the interpretation of near-surface geological structures. Detailed shallow structural geology can be imaged in the near surface, a data regime that is conventionally masked by the acquisition noise from the seismic acquisition. The shallow geological model comprises shallow lithological horizons as well as fault zones, the mapping of which may assist with the mitigation of shallow drilling risks. The integration of surface and subsurface structural mapping provides a tectonic framework for the delineation of reservoirs in the rift-faulted environment of the Gulf of Suez.

Description: A geomorphological assessment was undertaken to determine the risk of landslide damage to 38 km of the M25-M26 motorway underlain by the Gault Formation (a stiff clay to weak mudstone). Conventional methods for geomorphological mapping using stereoscopic aerial photography were found to be unhelpful, owing to the low topographic expression of landslips in the study area. In contrast, Light Detection and Ranging (LiDAR)-generated topographic contour maps proved invaluable, giving the landscape a pseudo-relief and allowing identification of the subtle landslide features. Relict (inactive) landslides were found to lack a definable backscarp and were mainly discernible by their indistinct toe lobes. Two types of active landslides were identified within the study area: slow creep failures barely distinguishable from relict slides, and rapid slides. A specific list of descriptors for landslides on Gault is presented based on the results of the geomorphological investigation. Four factors were found to be of particular importance in governing the potential for landsliding: the presence of relict slips; slopes of 7{degrees} or over; an abundant source of water; and close proximity to the top of the Gault where extremely high-plasticity Upper Gault crops out. The results of this investigation indicated that the section of motorway most affected by historical landsliding was also most at risk from future landslides. The similarity in morphology between active creep-type landslides and relict slides has implications for landslide management on Gault.

Description: The Antrim Lava Group (the basalts') and the underlying Ulster White Limestone Formation (the chalk') occupy a third of the land area of Northern Ireland. Neither sequence offers any significant groundwater resource potential but the basalt yields a baseflow contribution of 2630 Ml day-1 to the Lough Neagh catchment. Large spring discharges occur from the eastern outcrop of the chalk along the Antrim coast, giving the chalk a misleading reputation as a significant aquifer. These springs represent karstic risings from streams flowing off the basalt towards the sea, mixed with a small proportion of groundwater that has seeped through the basalt into the chalk below, although the concealed chalk aquifer is, for the most part, confined. Groundwater flow in the basalt is almost entirely of shallow catchment scale following preferred pathways within fossil soil horizons and other sub-horizontal discontinuities within the basalt sequence. Towards the periphery of the basalt some deeper circulation penetrates the chalk to discharge at outcrop. The main subcrop of the chalk is relatively impermeable with tighter jointing that is not favourable for transport or for storage. Available evidence indicates that little groundwater circulation in the chalk aquifer derives from direct rainfall recharge to the overlying basalts and that groundwater circulation is limited away from outcrop.

Description: Groundwater within the outcrop area of the Lincolnshire Limestone aquifer in eastern England is characterized by high (〉50 mg l-1) nitrate concentrations, whereas in the confined zone c. 15 km further east, nitrate concentrations are low (

Description: This study aims to assess the engineering properties of tufa. The engineering behaviour of tufa is dependent on the depositional environment, diagenesis and weathering characteristics. An engineering classification of tufa should include primary fabric, post-depositional changes and strength. The rock mass features of tufa include sedimentary structures resulting from frequently changing sedimentary environments, lithological variation owing to depositional and post-depositional changes, and cavities of primary and karstic origin. The tufa mass is therefore heterogeneous and description of the rock mass requires specialist experience. When there is core loss during drilling, it is difficult to decide if the zone of zero core recovery is a weak clastic tufa, a palaeosol, a crushed phytohermal tufa or a cavity. Antalya tufa exhibits a wide range of behaviour, ranging from loess-like collapsible soil to limestone-like hard rock. The unconfined compressive strength of rock tufas varies between 1 and 100 MPa. Collapsible tufas may have collapse potential up to Cp = 14%. Typical geohazards associated with engineering works on tufa include flexural failure, punching shear, consolidation settlement and punch failure, cave collapse, differential settlement of footings and excavation collapse. Special foundation and drainage measures are required to overcome the geohazards posed by tufa.

Description: Water has its own special characteristics, whether visible and flowing on the surface or invisible underground as groundwater. Owing to its mobility, water cannot be easily possessed; without it human survival and the living environment as we know it would not be possible. In European countries and their former colonies, including the Americas, water rights have their origins both in civil law from the European continent and in the common law of England. Both traditions viewed groundwater as the property of the owner of the land above it, who could use it as he pleased, irrespective of any impact to his neighbours. As long as abstractions remained small, questions of sustainability and impact to others and the environment did not arise. Technological progress in the last century caused an explosion in the quantities of groundwater abstracted. It was soon recognized that groundwater, even when renewable, is not inexhaustible and that its overexploitation can lead to unacceptable impacts. In the same period, intensive agriculture, urban expansion and industrial development led to the pollution of groundwaters in many countries. Impacts on both quantity and quality prompted legislative changes worldwide. Modern legislation has sought to control abstraction by introducing a system of permits or licences granted and regulated by the state, and to protect aquifers from pollution by introducing water quality standards and environmental regulations.

Description: The intrinsic vulnerability of the Chalk aquifer in East Anglia in eastern England to surface-derived contamination is dependent on the nature and juxtaposition of overlying Quaternary deposits. The study presented here is a direct investigation of the physical characteristics and pore water isotope composition of the glacial deposits found overlying the Chalk at five drilled locations in north Norfolk. The pore water isotopic composition demonstrated a range of {delta}18O values from -8.13 to -6.47{per thousand}, similar to the range for Chalk groundwater in the area of -8.18 to -7.01{per thousand}. A lithology-dependent model is developed that recognizes the presence of isotopically depleted palaeowater of late Pleistocene origin contained within layers of clay-rich till, adjacent to pore water containing modern meteoric water within layers of sand-rich till. The presence of (weathered) vertical fractures and intercalated lenses of sand- and gravel-rich layers is inferred to explain the occurrence of isotopically enriched water within the general mass of clay-rich till. It is apparent that groundwater movement in the heterogeneous lodgement till is controlled by advection in the more permeable sand-rich layers, whereas in the mass of clay-rich till, diffusion is more dominant. At one confined site, the observed pore water isotopic profile is modelled as having developed by downward diffusion of modern meteoric water during the past 5-10 ka.

Description: This study developed a neural network model for examining the performance of recycled concrete for the treatment of acidic groundwater. Concentrations of Al, Fe and Ca and alkalinity of the effluent were selected as the output parameters to simulate the performance of recycled concrete for neutralizing acidic groundwater. The input variables were the number of pore volumes, pH, oxidation reduction potential and the average hydraulic conductivity. Of the 658 experimental datasets available, 409 datasets were used for training, 184 datasets were used for validation, and the remaining datasets were used for cross-validation. The reported results indicate that the neural model is a valuable tool to assess and simulate the performance of recycled concrete. The sensitivity study confirmed that the selected input signals of the output estimate were equally important. A similar model could also be used for full-scale permeable reactive barrier installation provided that up-scaling issues such as the possible non-homogeneous nature of the recycled concrete and variation in groundwater quality can be effectively resolved.

Description: A tunnel extension to the Thames Water Ring Main has recently been completed in SE London. Two new deep shafts were built at either end, using jacked caisson construction methods. One of the shafts was excavated through much of the London Basin Palaeogene geological sequence and into the Chalk. It is the world's deepest large-diameter jacked caisson. Close geological supervision throughout the construction process validated the pre-construction ground model. This in turn has facilitated predictions of and contingency measures for adverse ground ahead of excavation. Observation and monitoring of the engineering behaviour of each of the stratigraphic units during construction has demonstrated how field data can be gained subsequent to the pre-construction ground investigation. In doing so, construction data have been used to augment and verify the ground investigation borehole and laboratory test data on which shaft design was based, in addition to providing assurances to the on-site construction team on the absence of unforeseen ground conditions.

Description: In the Three Gorges major landslides are the primary disasters, and endanger the normal running of the Three Gorges Dam and the life and property of the residents in the region. Hence, it is very important to formulate effective strategies for the prevention and remediation of landslides in this region, as part of which landslide mechanism analysis is an important task. In this paper, landslide mechanism analysis in the Three Gorges is carried out based on spatial data mining and knowledge discovery. The 1:50000 geological map, 1:10000 relief map and China-Brazil Earth Resources Satellite (Cbers) images were adopted to produce the key factors influencing landslide development, including engineering rock group, reservoir water fluctuation, vegetation coverage, slope structure, elevation, slope and aspect. A soft partition method was adopted to elevate the knowledge levels and formulate the quantification factors qualitatively based on the cloud model. In terms of these qualitative factors, a concept grid is built based on formal concept analysis and a concept grid algorithm. Based on this concept grid, the knowledge related to landslide mechanism is mined from the multi-theme landslide data, including the associations between the various factors that influence a landslide, the circumstances in which a landslide is easily triggered, and the relationship between landslide probability and factor combination. The experimental results show that the knowledge of landslide causes mined by our method possesses high confidence and is in agreement with the field circumstances. Therefore, the spatial data mining method proposed in this paper is suitable for landslide mechanism analysis. It can achieve the transformation between quantitative detection data of landslides and qualitative human mind, thereby leading to an innovative approach for landslide mechanism analysis.

Description: Measurements of the particle size distribution of samples of desert sand from the Great Sand Sea region of Libya are reported. The dune sands proper, being poorly (uniformly) graded, would not normally be regarded as suitable for making concrete, but the sand from the troughs between dunes, being well graded with little or no fines, would be acceptable as fine aggregate for concrete. Some observations are made on the grain morphology and texture of the particles in one sample in relation to its aeolian mode of formation.

Description: : The Mesoproterozoic Stoer Group of the ‘Torridonian' has been dated at 1177 ± 5 Ma (2), based on 40 Ar/ 39 Ar dating of authigenic K-feldspars precipitated in degassing structures within the Stac Fada Member, interpreted previously as an impact ejecta deposit. Fluid inclusion analysis of the K-feldspar shows that it precipitated from hot fluids, and so must immediately post-date emplacement of the ejecta blanket. The oxygen isotopic composition of K-feldspar is remarkably constant at 9.7 ± 0.2 (V-SMOW) and is consistent with derivation from evaporated lake water. The new age supports previous determinations of 1199 ± 70 Ma from Pb–Pb dating of limestone and 1180 Ma from palaeomagnetic data, but provides much higher precision. Supplementary material: The raw 40 Ar/ 39 Ar data, J-parameters, correction factors, air calibrations and blank data are available at http://www.geolsoc.org.uk/SUP18453 .

Description: : In this paper we reassess the geochronology and geochemistry of three dredge hauls from the SE corner of the Aves Ridge (Caribbean Sea) originally sampled in 1968 by Duke University's R.V. Eastward . Two hauls consist of light rare earth element-enriched granitoids with a U–Pb zircon emplacement age of 75.9 ± 0.7 Ma. A further haul contains mostly calc-alkaline island arc basaltic andesites of uncertain age. Petrological, trace element and isotopic constraints indicate that the granitoids have an oceanic crustal source and were formed by melting of the lower arc, oceanic or oceanic plateau crust. The mafic rocks formed by partial melting of an incompatible trace element-enriched mantle wedge, which was probably composed of mantle plume material. Both the dredged rocks and data from the Dutch–Venezuelan Antilles indicate a period of west-dipping underthrusting and subduction beneath, or close to, the Caribbean–Colombian Oceanic Plateau between c . 88 and c . 59 Ma, concurrent with collision of part of the plateau with northwestern South America. Constraints from the geochemistry and geochronology of offshore southern Caribbean arc and plateau rocks suggest that in the southern Caribbean there was no pre-existing west-dipping subduction system during formation of the Caribbean–Colombian Oceanic Plateau, whereas long-lived SW-dipping subduction in the northern Greater Antilles is more probable. Supplementary material: Sample details, major and trace element data (file 1), cathodoluminescence images of analysed zircons (file 2) and whole-rock standards (file 3) are available at http://www.geolsoc.org.uk/SUP18438 .

Description: : In the frontal part of the Rhenohercynian fold-and-thrust belt (High-Ardenne slate belt, Germany), two successive types of quartz veins, oriented normal and parallel to bedding respectively, are interpreted to reflect the early Variscan compressional tectonic inversion of the Ardenne–Eifel sedimentary basin. Fracturing and sealing occurred in Lower Devonian siliciclastic multilayers under very low-grade metamorphic conditions in a brittle upper crust. A geometrical and microthermometric analysis of these veins has helped to constrain the kinematic and pressure–temperature conditions of both vein types, allowing the reconstruction of the stress-state evolution in a basin during tectonic inversion. It is demonstrated that bedding-normal extension veins, which developed under low differential stresses and repeatedly opened and sealed (crack-seal) under near-lithostatic fluid pressures, reflect the latest stage of an extensional stress regime. Bedding-parallel veins, which developed at differential stresses that were still low enough to allow the formation of extension veins, cross-cut the bedding-normal veins and preceded the regional fold and cleavage development. These veins show a pronounced bedding-parallel fabric, reflecting bedding-normal uplift and bedding-parallel shearing under lithostatic to supra-lithostatic fluid pressures during the early stages of a compressional stress regime. This kinematic history corroborates that fluid overpressures are easy to maintain during compressional tectonic inversion at the onset of orogeny.

Description: : Classically, the North Sea Chalk is interpreted as having been deposited under quiet, homogeneous pelagic conditions with local redeposition in slumps and slides. Recent observations of highly discontinuous reflection patterns on 2D and 3D seismic reflection data from the NW European Chalk Group have led to a revision of some general ideas of chalk deposition, with the suggestion that long-lived, contour-parallel bottom currents exerted a primary influence on the development of intra-chalk channels, drifts and mounds. This study proposes an alternative explanation for the formation of selected intra-chalk seismic and stratal discontinuities, interpreting these as being caused by gravity-driven processes that developed in response to intense syndepositional tectonics. Submarine mass-transport systems identified in the study area include large-scale slumps, slides, debris flows and turbidites. The last occur in sinuous channel systems flanked by large master levees, with the channel fill exhibiting well-developed secondary banks and overbanks on the outer bends of the channel thalweg. This first documentation of channelized density-flow deposits in the North Sea Chalk has important consequences for the interpretation and prediction of redeposited chalk units, emphasizing at the same time the strength of detailed 3D seismic discontinuity detection for subsurface sedimentary-systems analysis.

Description: : The Late Devonian Svalbardian event relates to the final activity in the Caledonian Orogen, and affected Devonian strata in Spitsbergen by major folding, oblique thrusting and basement uplift. In southern Spitsbergen, the Devonian deformation and the complementary, presumed Mid-Carboniferous Adriabukta event deformation caused uplift of the Sørkapp–Hornsund basement high or horst. This high is fault-bounded by Devonian sandstones and a questionably aged Early or Mid-Carboniferous mudstone unit (Adriabukta Formation). The Adriabukta Formation at Hornsund occurs in the core of a major syncline, with underlying Devonian strata in the west limb, all truncated in the footwall by a steep, east-side-up oblique-reverse fault. Mid- to Late Carboniferous rifting reversed the motion and produced rift-fill deposits, and these strata overlie the deformed Devonian rocks and the Adriabukta Formation with an angular unconformity. A similar basin architecture and major syncline bounded by a reverse fault with lateral movement characterize the Svalbardian deformation in the Mimerdalen–Pyramiden area at Billefjorden farther north. Similarity also exists between a Late Devonian unit (Plantekløfta Formation) at Mimerdalen and the Adriabukta Formation at Hornsund, and we question the previous interpretation of the Adriabukta Formation as Carboniferous. Rather, we suggest that the Adriabukta and Svalbardian deformation events may have been part of the same event.

Description: : The provenance and exhumation history of paragneisses that enclose the 471–458 Ma eclogites in the Caledonian Jæren nappe, SW Norway, were constrained by performing U–Pb analysis on detrital zircon and Rb–Sr dating of mica. Zircon grains from four samples were analysed by laser ablation inductively coupled plasma mass spectrometry, providing detrital U–Pb ages between 3130 and 620 Ma. These data suggest Laurentian provenance, implying the existence of an early Caledonian (Taconian) HP fragment of Laurentian crust in the southern Scandinavian Caledonides. Several rims and recrystallized zircon patches yielded U–Pb ages averaging at 469 ± 6 Ma (2). These are identical to the Lu–Hf ages of the eclogites and underscore the importance of Taconian metamorphism in this part of the Caledonides. The main phengite Rb–Sr age cluster at 424.4 ± 4.6 Ma provides time constraints on the amphibolite-facies recrystallization of former high-Si phengite. Five out of seven biotite Rb–Sr ages were identical, yielding a weighted mean age of 413.6 ± 2.6 Ma. Low-Si phengite and biotite in three samples gave c . 400 Ma ages. The Rb–Sr data record the mid-crustal emplacement of the exotic Jæren nappe and its subsequent unroofing along the western edge of Baltica during the backsliding and collapse of the Scandian orogenic front. Supplementary material: The sample locations, U–Pb isotope data and ages for zircon, and the phengite and biotite major element data are available at http://www.geolsoc.org.uk/SUP18448 .

Description: : Plio-Pleistocene sediments exposed around the ophiolitic Troodos Massif document spectacular uplift from below sea level to a maximum height of c . 2000 m. Sedimentation reflects a dominant control of focused tectonic uplift, modified by the effects of glacio-eustatic sea-level change and climatic change. Understanding the uplift and controls on deposition has been hindered by an inadequate age model. Here, we present a preliminary investigation of the polarity of remanent magnetizations recorded within the upper part of the Pliocene succession in the Pissouri and Mesaoria basins and from the Pleistocene marine terrace deposits that border the Troodos Massif. When integrated with available lithostatigraphic and biostratigraphic data, the main results are as follows. Focused uplift of the Troodos Massif began during the Late Pliocene, either between 2.14 and 1.95 Ma or immediately prior to 1.77 Ma. Shallow-marine, ophiolite-derived clastic and bioclastic sediments accumulated in both the Mesaoria and Pissouri basins, implying that the Troodos Massif was uplifted as a single tectonic entity. Non-marine, deltaic and fluvial facies prograded into both of the basins during the Pleistocene (1.77 Ma–recent). Marine terraces in SW and south Cyprus were cut and covered by littoral sediments from 〈0.78 Ma, suggesting that high rates of uplift of the Troodos Massif persisted into mid- and late Pleistocene time.

Description: The use of inductively coupled plasma-mass spectrometry (ICP-MS) combined with liquid collectors greatly improved the reliability of the Metals-in-soil-gas' (MSG) technique in the late 1990s. To date, the MSG technique has been successfully applied in several locations varying in: commodity type (e.g. gold, base metals and nickel), depth of burial, and climatic regimes (e.g. from semi-arid through to wet temperate). In this paper, two case studies and a pilot study are reported to illustrate the effectiveness of the technique. The results show that in MSG, a suite of chalcophile elements, similar to the association of commodity and pathfinder elements in the deposits, exhibit sharp anomalies above the known sulphide mineralization. Copper and Zn peaks can reach tens of thousands of ppb over a background of

Description: Water systems from the P[a]durea Craiului Mountains and the northeastern extremity of the Pannonian Basin (Oradea-Felix) are investigated for deuterium, global salt content, and major solutes. All types of groundwater (springs, wellhead water, domestic wells, karst springs, cave water) display{delta} D values (-76.1{per thousand} to -62.3) similar to the surface running water (-76.5{per thousand} to -50.7), suggesting that they are meteoric in origin. The global salt content ranges from 49 mg/l to 1300 mg/l for the groundwater and from 46 mg/l to 665 mg/l for the surface water. From the co-variation between the{delta} D values, the global salt content, and the major solutes, as well as from the seasonal variation of these parameters, genetic links could be established. The mineralization of the groundwater is due to intense underground circulation, mostly in the karst system developed within the Mesozoic deposits of the P[a]durea Craiului Mountains.

Description: Acid mine drainage (AMD) is a particular focus of environmental research, involving the examination of many pollutants and their reactivity. Special attention must be paid for an accurate characterization of AMD samples in the field and in the laboratory. AMD samples are typically unstable due to the presence of colloidal material such as iron oxyhydroxides and bacteria. They induce physical and chemical transformations that may affect the analytical results. Variations in pH are recorded within days following sample collection, indicating changes in their chemistry. The present work demonstrates evidence of the instability of AMD samples, through the results of monitoring experiments performed under different laboratory conditions. Expeditious indicators, such as pH and electrical conductivity (combined with the analysis of crystallinity, composition and morphology of the resulting precipitates), allow monitoring of the evolution of the samples. The results also provide information about the transformation of the typical ochre products that precipitate from AMD, suggesting the formation of schwertmannite and its evolution to a more crystalline mineral.

Description: Passive systems with constructed wetlands are designed to simulate natural attenuation processes in order to treat mine water in a long-term and cost-effective manner. In this way, they are especially appropriate to treat mine water discharging from abandoned mines. This paper presents geochemical and mineralogical data obtained from a recently constructed passive system in the Jales abandoned mine, north Portugal. It shows the role of fresh ochre-precipitates, formed as waste products from the neutralization process, in the retention of trace elements. Chemical analysis of these waste products revealed strong enrichment factors for metals and arsenic, relative to the water from which they precipitate. The mineralogical study shows that ochre-precipitates are poorly ordered iron-rich material, such as ferrihydrites, that occur as small spherical aggregates (

Description: Exploration for deep-seated mineral deposits in mature mining camps requires integration of large and heterogeneous spatial data-sets. Traditionally, geological, geochemical, and geophysical observations are acquired, processed and analysed independently within separate spatial contexts or more commonly, for geochemical data, in non-spatial feature space. Although methodological developments are still in progress, 3D GIS (geographic information system) technologies already provide powerful tools that can be used to integrate such heterogeneous data-sets to visualize, compare, and characterize geological relationships in a more supportive interpretive environment. Importantly, this technology provides better opportunities to embed all these properties in a more robust geometric framework in which structural history and palaeogeographic setting can be taken into account. We present 3D GIS applications that aid in interpreting relationship patterns amongst faults, folds and geochemical trends. Examples from the Noranda mining region, a classic VMS mining camp, demonstrate the applicability of 3D GIS to support the discovery of new mineral resources at depth.

Description: Iron occurs naturally as Fe2+, Fe3+, and, to a lesser extent, as Fe0. Many fundamental (bio)geochemical processes are based on redox cycling between these oxidation states. Mossbauer spectroscopy provides quantitative information about the distribution of Fe among its oxidation states, identification of Fe-bearing phases, and relative distribution of Fe among those phases. Portable, miniaturised Mossbauer spectrometers were developed for NASA's Mars Exploration Rovers (in operation since 2004) and provide a means for non-destructive, in-situ field investigations. On Mars, these instruments provided evidence for aqueous activity with implications for habitability, were applied in geological mapping of the landing sites, and helped to identify meteorites, for example. On Earth, they were used in field studies of green rust, the identification of air pollution sources, or the study of archaeological artefacts. Their application to in-situ resource utilisation (ISRU) on the Moon has been demonstrated in a recent NASA field test of hardware for oxygen production. A new detector system in an advanced version of these instruments is based on Si Drift Detectors and permits the simultaneous acquisition of X-ray fluorescence spectra to determine elemental compositions.

Description: Sampling around the Ni-Cu deposits in the northern Thompson Nickel Belt (TNB), central Canada, was conducted to document Ni-Cu mineralization signatures in till. Samples used in this study include archived material collected in 1996 and new samples collected in 2005 and 2006. During the Late Wisconsinan, the Laurentide Ice Sheet flowed southwestward and subsequently westward across the TNB striating outcrops and transporting metal-rich till. Exploration along the belt and in the surrounding terranes should consider both the older SW and younger westward ice flow events when interpreting and following up till geochemical results. Till geochemistry of the 3 offer further discrimination of significant till geochemical anomalies. Using the deposit signatures in till as a guide, five anomalous till samples outside the belt represent new exploration targets because they contain significant elevated concentrations of, in various combinations, Pt, Pd, Cu, Cr, Mo, Sb, Bi and Fe.

Description: Soils from the vicinity of the Endeavor Mine, in the Cobar region of western NSW, have been sieved into the (a) 2-4 mm, (b) 1-2 mm, (c) 0.5-1 mm, (d) 250-500 {micro}m, (e) 125-250 {micro}m, (f) 63-125 {micro}m and (g)

Description: The Pinguino deposit is characterized by the presence of indium-rich polymetallic vein mineralization representing an atypical epithermal occurrence for the low sulphidation epithermal mineralization from the Deseado Massif, Patagonia, Argentina. Polymetallic veins display high In, Zn, Pb, Ag, Cd, Au, As, Cu, Sn, W and Bi values represented by complex sulphide mineralogy. Mineralization developed in two main stages: a Cu-Au-In-As-Sn-W-Bi stage, and a Zn-Pb-Ag-In-Cd-Sb stage. Correlation coefficients are used to estimate the degree of inter-relation between metals concentrations in each stage and specifically to determinate the behaviour of indium. Indium concentrations show a wide range (3.4-1184 ppm In) and, based on the correlation coefficients of ore geochemistry, in the first stage indium is associated mainly with Sn, present in ferrokesterite and cassiterite, while the highest indium values are related to the late mineralization stage, closely associated with Zn and Cd and present in the Fe-rich sphalerite, the most important In-bearing mineral in the deposit.

Description: Petrography has been used by geologists to investigate rocks for over 150 years. More recently, petrographic techniques have been applied to the investigation of a wide range of construction geomaterials, most notably building stone, aggregates, concrete and mortar. The service life performance of buildings and infrastructure assets is dependent on good design and specification, the availability of high-quality construction materials, good construction workmanship and adequate maintenance. This paper reviews the state of practice for the petrography of geomaterials, as applied to construction projects worldwide. Petrographic methods and standards specific to geomaterials are introduced. Application of the techniques at various stages of the life cycle of structures is discussed including resource assessment, quality assurance, condition assessment, forensic engineering of failures and conservation of historic buildings. The contribution of petrography to sustainable construction is also discussed.

Description: The southwestern region of Sri Lanka is underlain mainly by Precambrian metasedimentary rock sequences consisting of charnockites, gneisses and migmatites. Along the Southern Expressway, charnockites occur extensively as boudinage structures of different dimensions (mini- and mega-) enveloped or wrapped by gneissic rock bands. As a result of characteristic tropical intense precipitation and extreme weathering conditions of the area, gneissic rocks decompose to loosely bound lateritic soils or hard lateritic cover. The lowermost parts of rock cuttings along the expressway show the occurrence of charnockite boudins wrapped within less competent gneisses that have weathered into lateritic soils. Weathering and erosion processes weaken the bond between gneisses and the boudins, resulting in some of the more competent boudins becoming detached and falling to the ground, leaving voids in the cut slopes and thereby making the slopes more vulnerable to erosion. However, on weathering, gneissic bands when not associated with boudinage structures were observed to develop hard lateritic covers at the top of cut slopes. In some cuttings, boudins are associated with highly folded, pegmatite-rich migmatitic gneisses that weather more rapidly than banded gneisses. Erosional features such as gullies and cavities cause large-scale instability owing to collapse of weathered rocks and soils, giving rise to slope failures.

Description: The geology of the Chalk beneath east London and the Thames Gateway is reviewed and key features affecting engineering geology are summarized. In particular, the variable stratigraphy preserved beneath the sub-Palaeogene erosion surface, the evidence for syndepositional tectonics in the Chalk, and the recognition of tectonic fractures and strata-bound fracture systems are emphasized. The contrasting physical properties of chalk and flint are discussed and the depth of weathering in the subcrop and outcrop are compared and contrasted. The information gained from separate ground investigations is combined to suggest that there are regions in east London where better quality chalk and less permeable ground are present between regions of poorer quality chalk with higher permeability, closely related to zones of faulting.

Description: The IPCC global sea-level rise projections made in 1990 set the framework for the coastal policy response to sea-level rise in England and Wales. It was predicted that sea-level rise would result in an increase in wave energy at the cliff foot and accelerated cliff recession. The 50 year recession records for the Holderness cliffs, UK, have been examined to establish whether there has been acceleration in recession rates since the early 1990s. As relative sea level has risen over the second half of the 20th century, so have Holderness cliff recession rates, from around 1.2 m a-1 in the early 1950s to around 1.5 m a-1 by 2000. However, there has been no significant acceleration in the rate of global sea-level rise since 1990 and no rapid increase in the recession rate. However, the Holderness data series may show responses to decadal-scale sea-level changes associated with the 18.6 year nodal tidal cycle.

Description: In this study, variations in optimal pump-and-treat (P&T) remediation designs and costs for a contaminated and mass-transfer-limited aquifer are investigated for different hydraulic conductivity (K) heterogeneity conditions with focus on the influence of the correlation length ({lambda}) of spatially variable K values. Several heterogeneous K fields with diverse {lambda} values and variances ({sigma}2) are considered. The impact of {lambda} on optimal remediation design selection is analysed considering different relative locations of low and high K regions. Furthermore, optimal designs obtained for different initial contaminant plume configurations are evaluated. Optimal designs are determined using a simulation-optimization approach. Results show that the locations of low and high K zones within an aquifer, and their respective areas defined through {lambda}, affect remediation design and cleanup cost noticeably. It is observed that in addition to typical geostatistical parameters ({lambda} and {sigma}2), better determination of both the spatial distribution of low and high K regions and the initial contaminant mass is critical for better P&T design.

Description: Laboratory mechanical tests were carried out to study the intrinsic variability of rock salt specimens obtained from the Middle and Lower members of the Maha Sarakham formation in the Khorat basin. Prior to the mechanical tests, the types and amount of inclusions were identified by visual examination and after testing by X-ray diffraction and dissolution methods. The uniaxial compressive strength of the specimens linearly increases from 27 MPa to about 40 MPa as the anhydrite content (by weight) increases from 0% (pure halite) to 100% (pure anhydrite). The combined stiffness of the salt and the anhydrite causes an increase of specimen elasticity from 22 GPa (pure salt) to as high as 36 GPa (pure anhydrite). Tensile strengths increase with increasing anhydrite content, particularly when the content is above 60% by weight. Below this limit the anhydrite has an insignificant impact on the specimen tensile strength. The tensile strength of salt crystals can be as high as 2 MPa, whereas that of the inter-crystalline boundaries is 1 MPa. The visco-plasticity increases exponentially with crystal size, as dislocation glide mechanisms become predominant for the specimens comprising large crystals. Salt specimens with fine crystals deform by dislocation climb mechanisms, and hence reduce the specimen's visco-plasticity. The true understanding of the impact of the inclusions on the mechanical properties of the salt is important for the design and stability analysis of underground mines and storage caverns.

Description: In the design of major construction works, the better the ground conditions are known, the more control there is on the assessment of risks for construction, contract and personnel, and ultimately on final costs. Understanding of the ground conditions is usually expressed as a conceptual ground model that is informed by the results of desk study and of dedicated ground investigation. Using the GSI3D software, a 3D geological model (a model composed of attributed solid volumes, rather than of surfaces) can be constructed that exactly honours geologists’ interpretations of the data. The data are used in their true 3D position. The 3D model of faulted Lambeth Group (Palaeogene) strata in the area of the proposed new Crossrail Farringdon underground station, in central London, has several types of benefit. These include allowing optimum use of available ground investigation data, including third party data, with confidence. The model provides an understanding of the local geological structure that had not been possible using other commonly used methods: in particular, it shows the likely distribution of numerous water-bearing coarse deposits and their faulted offsets, which has potentially significant effects on groundwater control. The model can help to focus ground investigation, constrain design and control risk.

Description: Six types of sedimentary stone (four bioclastic calcarenites, one calcitic sandstone and one calcitic dolostone) commonly used as building materials were studied from a petrophysical point of view and their durability was evaluated. The following analytical techniques were used: X-ray diffraction, polarizing optical microscopy, hydric tests, mercury intrusion porosimetry, ultrasound, salt crystallization cycles, freeze–thaw cycles and colorimetry. The hydric behaviour of the stones is affected by their different textures. The most compact stone absorbs less water compared with the other samples and has the lowest open porosity; however, more porous and less compact stones achieved better results in terms of the degree of pore interconnection and the drying rate. All the stones have unimodal pore size distribution and most pores had radii of 10 μm or less. Accelerated ageing tests caused some changes in the colour of stones and, above all, the loss of fragments, especially during salt crystallization cycles. The main causes of decay were the different mineralogy between the grains and the matrix in the sandstone and a strong anisotropy owing to the presence of sedimentary planes in one calcarenite. On the basis of our results we then ranked the stones according to their quality as building materials.

Description: Oceanic and continental lithosphere distribution within the eastern Mediterranean is not well understood. A gravity inversion, incorporating a lithosphere thermal gravity anomaly correction, has been used to map Moho depth, crustal thickness and lithosphere thinning for the eastern Mediterranean, from which the distribution of oceanic and continental lithosphere, the structure of the ocean–continent transition (OCT) and the location of the continent–ocean boundary (COB) can be determined. The gravity inversion results show thin crust and high continental lithosphere thinning under the Ionian Sea and the Herodotus Basin, consistent with these basins being underlain by oceanic crust. Moho depths from gravity inversion are in agreement with seismic refraction estimates in these basins. Highly thinned continental crust is predicted under the offshore Sirte and Levant basins. The sharp decrease in crustal thickness predicted by gravity inversion off the Libyan and Egyptian coast gives an indication of COB location. Crustal thickness and continental lithosphere thinning determined from gravity inversion have also been used to explore the relationship between the Cretaceous West and Central African Rift System (WCARS: Benue Trough, Chad, Central African Shear Zone (CASZ) and Sudan basins) and the eastern Mediterranean basins; continuity between the Cretaceous WCARS and the eastern Mediterranean basins is not apparent in the gravity inversion results.

Description: There is significant opportunity in re-working older data with modern geophysical technology to develop new plays and concepts in the northern and eastern Mediterranean. New exploration success and higher commodity prices have encouraged both majors and independents to reconsider the Mediterranean as a viable entry point to North African and Southern European energy markets. Two case studies in the Adriatic Sea and Levantine Basin are examined for play concepts and leads using vintage seismic data re-imaged with modern imaging techniques integrated together with a geologically driven workflow. The Adriatic was selected based upon maturity of hydrocarbon discovery; in comparison the Levantine Basin ranks as a region of new territory which we are only just beginning to understand.