ALBERT

Description: Seismic reflection and refraction profiles, and potential field data, complemented by crustal-scale gravity modelling, plate reconstructions and well cross-sections are used to study the evolution of the South Segment of the South Atlantic conjugate margins. Distinct along-margin structural and magmatic changes that are spatially related to a number of conjugate transfer systems are revealed. The northern province, between the Rio Grande Fracture Zone and the Salado Transfer Zone, is characterized by symmetrical seawards-dipping reflections (SDRs) and symmetrical continent–ocean transitional domain. The central province, between the Salado Transfer Zone and the conjugate Colorado–Hope transfer system, is characterized by along-strike tectonomagmatic asymmetry. The Tristan da Cunha plume, located on the central province of the South Segment, may have influenced the volume of magmatism but did not necessarily alter the process of rifted margin formation. Thus implying that, apart from voluminous magmatism, the extensional evolution of the central province of the South Segment may have much in common with ‘magma-poor’ margins.

Description: This chapter presents a synthesis of the pre-break-up plate tectonics of western Gondwana and the pre- and syn-rift magmatism in the SW South Atlantic margin (Brazil, Uruguay and Argentina) and the conjugate African continental margin (Angola, Namibia and South Africa). An updated database of the geographical locations of the primary available radiometric ages is also included in this work. A systematic analysis of the K–Ar and Ar/Ar ages from outcrops and boreholes shows a marked Mid to Late Jurassic peak in the southernmost segment of the South Atlantic, related to the emplacement of the Karoo volcanics in South Africa and in Argentina (including the Falkland Islands), and an important Early Cretaceous peak with age distributions that are related to the Gondwana break-up and formation of rift basins along the incipient continental margins. In both the southern Brazilian and Argentinian margins, as well as in the conjugate Namibian and South African margins, several igneous centres and basaltic lava flows are suggestive of the influence of mantle plumes in the Early Cretaceous, which were heralded by mafic dyke swarms in Argentina, Brazil, South Africa and Namibia.Supplementary material: A complete table with Radiometric ages of Jurassic–Early Cretaceous magmatism in the southern portion of West Gondwana is available at: www.geolsoc.org.uk/SUP18589

Description: Conservational models, like simple shear, pure shear or polyphase models that exclude exchanges between the lower continental crust and upper mantle, are usually proposed to explain the lithospheric stretching and consequent crustal thinning of passive continental margins. These models need large amounts of horizontal movement, and have, therefore, important implications for plate kinematic reconstructions and intraplate deformation. In this paper we propose to show these implications in the Central Segment of the South Atlantic Ocean. In the Angola–Brazilian system, these models imply about 240 km of horizontal movement. This movement can be compensated by two end-member mechanisms: (1) an intraplate deformation located in Africa; and (2) an intraplate deformation located in South America. We detail for each solution the strong geological and geodynamical implications, and discuss the consequences for the genesis of passive continental margins.

Description: This work integrates the available geological information and geochronology data for the Cretaceous–Recent magmatism in the South Atlantic, represented by onshore and offshore magmatic events, including the oceanic islands along the transform faults and near the mid-ocean ridge. The analysis of the igneous rocks and their tectonic settings allows new insights into the evolution of the African and Brazilian continental margins during the South Atlantic opening. Following the abundant volcanism in the Early Cretaceous, the magmatic quiescence during the Aptian–Albian times is a common characteristic of almost all Brazilian and West African marginal basins. However, rocks ascribed to the Cabo Granite (104 Ma) are observed in NE Brazil. In West Africa, sparse Aptian–Albian ages are observed in a few coastal igneous centres. In the SE Brazilian margin, an east–west alkaline magmatic trend is observed from Poços de Caldas to Cabo Frio, comprising igneous intrusions dated from 87 to 64 Ma. Mafic dyke swarms trending NW also occur in the region extending from the Cabo Frio Province towards the Central Brazilian Craton. On the West African side, Early Cretaceous–Recent volcanism is observed in the Walvis Ridge (139 Ma), the St Helena Ridge (81 Ma) and the Cameroon Volcanic Line (Early Tertiary–Recent). Volcanic islands such as Ascencion (1.0–0.65 Ma), Tristão da Cunha (2.5–0.13 Ma) and the St Helena islands (12 Ma) most probably correspond to mantle plumes or hot spots presently located near the mid-Atlantic spreading centre. Within the South America platform and deep oceanic regions, the following volcanic islands are observed: the Rio Grande Rise (88–86 Ma), Abrolhos (54–44 Ma), the Vitória–Trindade Chain (no age), Trindade (2.8–1.2 Ma) and Fernando de Noronha (12–1.5 Ma). There are several volcanic features along the NW–SE-trending Cruzeiro do Sul Lineament from Cabo Frio to the Rio Grande Rise, but they have not been dated. The only known occurrence of serpentinized mantle rocks in the South Atlantic margin is associated with the Saint Peter and Saint Paul Rocks located along the São Paulo Fracture Zone. The Cameroon Volcanic Line in NW Africa is related to the magmatism that started in the Late Cretaceous and shows local manifestations up to the Present. The compilation of all available magmatic ages suggests an asymmetrical evolution between the African and South America platforms with more pre-break-up and post-break-up magmatism observed in the Brazilian margin. This is most likely to have resulted from the different geological processes operating during the South Atlantic Ocean opening, shifts in the spreading centre, and, possibly, the rising and waning of mantle plumes.Supplementary material: A complete table with radiometric dates that have been obtained by universities, government agencies and research groups is available at: www.geolsoc.org.uk/SUP18596

Description: We present a synthesis based on the interpretation of two pairs of deep seismic reflection crustal sections within the Southern Rift System (SRS) separating Australia and Antarctica. One pair of sections is from the conjugate margins between the Great Australian Bight (GAB) and Wilkes Land, in the central sector of the SRS, which broke up in the Campanian. The second pair of conjugate sections is located approximately 400 km further east, between the Otway Basin and Terre Adélie, which probably broke up in Maastrichtian time. Interpretations are based on an integrated synthesis of deep multi-channel seismic, gravity and magnetic data, together with sparse sonobuoy and dredging information, and the conjugate sections are presented with the oceanic crust removed beyond the continent–ocean boundary (COB).At first order, both conjugate pairs show a transition from thinned continental crust, through a wide and internally complex continent–ocean transition zone (COTZ), which shows features in common with magma-poor rifted margins worldwide, such as basement ridges interpreted as exhumed subcontinental mantle. In the central GAB sector, the COTZ is symmetric around the point of break-up and displays a pair of mantle ridges, one on each margin, outboard of which lies a deep-water rift basin. Break-up has occurred in the centre of this basin in this sector of the SRS. In contrast, the Terre Adélie margin is nearly 600 km wide and shows an abandoned crustal megaboudin, the Adélie Rift Block. This block is underlain by interpreted middle crust, and appears to have a mantle ridge structure inboard, as well as an outboard exhumed mantle complex from which mylonitized harzburgite has been dredged. The conjugate margin of the Beachport Sub-basin is relatively narrow (c. 100 km wide) and does not appear to contain an exhumed mantle ridge, as observed along strike in the GAB.These observations from a single rift spreading compartment show that radically different break-up symmetries and margin architectures can result from an essentially symmetric rifting process involving multiple, paired detachment systems. This indicates the need for caution in interpreting causative mechanisms of rifting from limited conjugate sections in other rifts. We speculate that the underlying crustal composition, rheology and structural preconditioning play a significant role in partitioning strain during the transition to break-up.

Description: Hyperextended, magma-poor margins are characterized by a wide continent–ocean transition and anomalously small fractions of magmatism during mantle exhumation prior to oceanic spreading. Here, I bring together several aspects of their rift to drift transition and give a coherent picture of their evolution from platform to deep-sea environments. I focus mainly on the West Iberia Margin (WIM)–Newfoundland (NF) conjugates in the North Atlantic Ocean. The architectural evolution of these margins is characterized by upper-crustal faulting and lower-crustal deformation that are tightly coupled, resulting in fault displacement that is accompanied by underlying, equal and coeval crustal thinning. Lower crust deforms first ductilely, but then progressively switches to brittle due to enhanced conductive cooling at very slow extension velocities (〈c. 6 mm a−1 half-rate). The switch from ductile to progressively brittle lower crust is accompanied by the emergence of a dominant basinwards fault dip and oceanwards younging of fault activity. It is shown that these processes, acting in concert: (1) reconcile the horizontal extension on faults with crustal thinning without the need of lower-crustal flow; (2) explain, within one common Andersonian framework (faults active at 65°–30°), the change in fault geometry from planar to listric to detachment-like with increasing extension; and (3) generate the tectonic asymmetry observed between conjugate pairs. This work also discusses a high-resolution seismic section of the WIM showing that the ‘detachment-like’ fault S is truncated prior to the peridotite ridge where mantle exhumation first takes place. This suggests that serpentinized mantle rises due to its own buoyancy, separating and pulling the thinned crustal blocks apart. Once the crust has been separated, further mantle exhumation takes place by magma-poor extension of the underlying mantle. I show with numerical models that either a small reduction of mantle potential temperature (c. 25–50 °C), a mantle depletion of more than 10% or very slow half-extension velocities (c. 6 mm a−1) are required to reproduce the small amount of magmatism inferred. Available observations support either a very slow extension velocity or a smaller than normal mantle temperature; however, estimation errors may be large. Ultimately, unravelling which of these factors most contribute to magma-poor mantle exhumation will provide an improved understanding of the mantle lateral homogeneity and the three-dimensional nature of the rifting to drifting process.

Description: The İspendere ophiolite forms part of the Tauride active continental margin assemblage in SE Anatolia. The ophiolite exhibits an intact oceanic lithosphere section and is intruded by Late Cretaceous calc-alkaline granites. The ophiolite comprises mantle tectonites, ultramafic to mafic cumulates, isotropic gabbros, isolated diabase dykes, a sheeted dyke complex, plagiogranite and volcanic rocks. The volcanics and the sheeted dyke complex exhibit (1) similar rare earth element patterns, with flat to light rare earth element depletion (La–Yb)N=0.71–1.14 and 0.65–1.22, (2) negative Nb anomalies and (3) flat-lying high field strength element trends. These features differ from a typical Normal--Mid Ocean Ridge Basalt fractionation trend and could have resulted from c. 15% partial melting of a previously depleted mantle source. The whole-rock chemistry and the mineral chemistry of the ultramafic to mafic cumulates [high Ca plagioclases (An89–81), magnesian olivines (Fo88–81) and clinopyroxenes (Mg#90–83)] show that the primary magma of the plutonic suite is compositionally similar to modern island arc tholeiites. The available evidence suggests that the İspendere ophiolite formed at a northerly supra-subduction zone spreading centre of the Southern Neotethys, between the Taurides and the Bitlis–Pütürge metamorphic units, during the Late Cretaceous. Comparison with the adjacent Göksun, Kömürhan and Guleman ophiolites suggests that the İspendere ophiolite represents part of a single regional-scale sheet of oceanic lithosphere that was accreted to the base of Tauride active continental margin where it was cut by arc-type magmatic rocks.

Description: The development of the central Tauride region was dominated by rifting and passive margin development during Triassic–Early Cretaceous. The Tauride continental margin was later destabilized, followed by subsidence and collapse to form a flexurally controlled foredeep. Volcanic–sedimentary mélange and ophiolitic rocks were thrust onto the northern margin of the Tauride carbonate platform (Geyik Dağ) during Campanian–Maastrichtian. The remaining non-emplaced Tauride shelf subsided to form a second-stage foredeep during the Eocene. This basin was finally over-ridden by large thrust slices of Tauride shelf sediments, represented by the Hadim and Bolkar nappes, together with previously emplaced continental margin and ophiolitic units. Large- and small-scale field kinematic data indicate regional emplacement towards the west or SW. The ophiolitic rocks and related mélange were emplaced directly onto the Tauride autochthon (Geyik Dağ) in response to regional-scale out-of-sequence thrusting. Localized backthrusting to the NE took place in a transpressive setting. In the south, the relatively distal Bolkar nappe was emplaced over the more proximal Hadim nappe to produce the present thrust stacking order. The two-phase emplacement reflects initial northward subduction, which culminated in trench-continental margin collision (Campanian–Maastrichtian). This was followed by continent–continent collision (Eocene) related to suturing of a Mesozoic ocean basin to the north.

Description: The Ankara–Erzincan suture zone includes large bodies of ophiolite and ophiolitic melange in northeastern Anatolia. The ophiolitic bodies are (1) Refahiye (Erzincan), (2) Şahvelet (Erzurum), (3) Karadağ (Erzurum) and (4) Kırdağ (Erzurum). The ophiolite-related units include well-preserved sections of oceanic lithospheric and accretionary melanges with local blueschist assemblages. The ophiolite-related units in NE Anatolia are unconformably overlain by Campanian–Maastrichtian-aged sediments that were later imbricated with the ophiolitic rocks. Geochemical data for the individual ophiolite sections indicate a tholeiitic composition, depletion in Nb, enrichment in large ion lithophile elements, parallel to slightly depleted high field strength element patterns (compared with normal-mid ocean ridge basalt), and slightly light rare earth element-depleted to parallel rare earth element trends. These features suggest progressive source depletion towards island arc tholeiites and finally boninites. A fore-arc setting is proposed for the generation of the ophiolites. In contrast, the volcanic rocks from the mélange units exhibit tholeiitic to alkaline compositions and either depletion or enrichment of rare earth element and high field strength elements. Seamount-type alkaline and subduction-related tholeiitic basaltic rocks were apparently juxtaposed during subduction/accretion. Models involving either a single north-dipping subduction zone or two north-dipping subduction zones may be applicable. Both models involve the generation of supra-subduction zone-type ophiolites in a forearc setting, an accretionary prism (with blueschists) and a volcanic arc during the Late Cretaceous. The ophiolites, ophiolitic melange and related blueschists were emplaced either northwards onto the Pontide margin or southwards over the passive margin of the Tauride platform.

Description: New data for regionally important granulite facies metaophiolitic rocks and cross-cutting granitoids rocks are presented and discussed. The high-temperature/high-pressure Berit metaophiolite is cut by unmetamorphosed Eocene (51–45 Ma) granitoid rocks. The highest metamorphic grade occurs in blocks of mafic granulites. Enveloping amphibolite facies rocks reflect retrograde metamorphism related to exhumation. Sm–Nd (pyroxene–garnet–amphibole–whole rock) isochron ages of 52–50 Ma for the granulite facies rocks are interpreted to represent the time of cooling of the granulite facies rocks. The over-riding Malatya metamorphic unit to the north is also intruded by Eocene granitoid rocks. The granulite facies metamorphism of the meta-ophiolitic rocks is inferred to have formed in the roots of an Eocene magmatic arc, with accentuated heat flow being provided by subduction of a spreading ridge, or rupture of the subducting slab. The high-temperature/high-pressure metamorphism was followed by exhumation, as indicated by field structural relations and the evidence of retrograde metamorphism. The Eocene arc magmatism can best be explained by northward subduction of the Southern Neotethys, which persisted after the time of latest Cretaceous regional ophiolite emplacement until the collision of the Eurasian (Anatolian) and Arabian continents during the Early–Mid Miocene. Subsequent Plio-Quaternary left-lateral strike-slip strongly affected the area.Supplementary-material: Four supplementary tables giving the whole rock geochemistry of the granitoids, mineral geochemistry of the granulite facies rocks, LA-MC-ICP-MS zircon U–Pb data belonging to granitoids and Sm–Nd data belonging to granulite facies rocks and two documents giving the detailed analytical procedures and detailed petrography of the granitoids are available at www.geolsoc.org.uk/SUP18588

Description: The El-Kabir Lineament and the El-Kabir Basin further south form part of the southernmost of several sinistral strike-slip lineaments that characterize the distributed Africa–Eurasian collision zone in the easternmost Mediterranean region. Based on onshore field evidence and offshore two-dimensional (2D) seismic evidence, the El-Kabir fault lineament is interpreted as a sinistral strike-slip fault zone that was active at least from Middle Eocene time onwards. The El-Kabir Lineament was probably active in a transpressional mode during Middle Eocene–Early Miocene(?). The fault lineament was then active in a transtensional mode during Miocene–Recent time. The transtension resulted in the formation of the adjacent NE–SW El-Kabir Basin. Continuing subsidence provided the accommodation space for thick sediment accumulation (〉3 km) within the El-Kabir Basin and its offshore extension (roughly corresponding to the Latakia Basin). Offshore 2D seismic data confirm that the basin is fault-bounded and that it continued to be active during Pliocene–Recent time. To the NE, the NE–SW El-Kabir Lineament is truncated and offset by the north–south-trending Dead Sea Transform Fault Zone (Ghab Graben), which propagated northwards during the Pliocene. The inferred Neogene–Recent transtension is explicable by kinematic linkage with oceanic crust in the easternmost Mediterranean that is likely to have experienced contemporaneous subduction zone rollback.

Description: A transition from construction to collapse of the Alpine orogen in Middle to Late Eocene time is recorded in the structural fabrics of gneissic rocks in the southern Menderes Massif, western Turkey. Augen gneiss in the southern Menderes Massif indicates a spatial switch of shear sense along a north–south section through the complex (top-to-north shear in the north and top-to-south in the south). This ‘kinematic hinge’ corresponds to a broad zone of dominant pure shear where crust underwent vertical thinning and approximate north–south extension. During this extension, foliation became corrugated with fold axes parallel to lineation, indicating inflow from neighbouring crust to the east and the west. Published geochronologic work suggests a Middle to Late Eocene age for this dominant fabric. Thermal weakening of felsic Menderes crust beneath Alpine nappes may have triggered this orogenic collapse. Deformation fabrics developed at temperatures of c. 550 °C, and progressive cooling during collapse generated strain localization within a kilometre-thick shear zone at the southern margin of the Menderes Massif. In the southern Menderes, the corrugation of foliation indicates that Middle to Late Eocene flow was constricted into an orogen-perpendicular direction. This behaviour is similar to the collapse and orogen-parallel extension of the European Alps (Lepontine dome, Tauern Window).

Description: According to the literature, the Adana Basin, at the easternmost part of the Mediterranean Basin in southern Turkey, records the Pliocene stage with shallow-marine to fluvial deposits. Our micropalaeontological analysis of samples from the Adana Basin reveal Late Lago–Mare biofacies with Paratethyan ostracod assemblages pertaining to the Loxocorniculina djafarovi zone. Grey clays rich in planktonic foraminifera lie above the Lago–Mare deposits. Within the grey clays, the continuous occurrence of the calcareous nannofossil Reticulofenestra zancleana and the base of the Reticulofenestra pseudoumbilicus paracme points to an Early Zanclean age (5.332–5.199 Ma). Both ostracod and benthic foraminifera indicate epibathyal and bathyal environments. 87Sr/86Sr measurements on planktonic and benthic foraminifera fall below the mean global ocean value for the Early Zanclean, indicating potentially insufficient mixing of low 87Sr/86Sr Mediterranean brackish ‘Lago–Mare’ water with the global ocean in the earliest Pliocene. We utilize the ages and palaeodepths of the marine sediments together with their modern elevations to determine uplift rates of the Adana Basin of 0.06 to 0.13 mm a−1 since 5.2–5.3 Ma (total uplift of 350–650 m) from surface data, and 0.02–0.13 mm a−1 since c. 1.8 Ma (total uplift of 30–230 m) from subsurface data.Supplementary material: Microphotographs of foraminifers, ostracods, and calcareous nannofossils, plots of the calcareous nannofossil frequencies, occurrence of foraminifers and ostracods in the study sections, results of Sr isotopic analysis, and a complete list of fossils are available at www.geolsoc.org.uk/SUP18535.

Description: Late Cenozoic tectonics affected the evolution of the Euphrates river valley in northern Syria. Data on the height and composition of terraces and new K–Ar dating of overlying basalts are presented for the area between the Assad Reservoir and the town of Abou Kamal. The presence of the Late Cenozoic Euphrates Fault, longitudinal with respect to the valley, is established by the lower height of the terraces on the NE side of the valley compared with the same terraces on the SW side. Geophysical profiling (dipole axial sounding; correlation refraction method and georadar) across the southern side of the valley (opposite the town of Ar Raqqa) confirms the offset on the fault as 〉25 m. Movements along the transverse Rasafeh–El Faid fault zone and the Halabiyeh–Zalabiyeh deformation zone have resulted in local uplift and the splitting of river terraces. During the Pliocene–Early Pleistocene, uplift and strong incision of the Euphrates valley propagated from near the Syrian–Turkish border to near the Iraq–Syrian border. The Euphrates began to deposit alluvium onto the pre-existing low-lying Mesopotamian Foredeep at c. 3.5 Ma. Intense incision began by late Late-Pliocene time to form terrace IV. Comparable incision further downstream began during the Early Pleistocene to form terrace III.

Description: New fault data are presented for the Karasu Valley, southern Turkey. Field measurements concentrate on the Eocene–Miocene (c. 48–7 Ma) sediments exposed on the south-western rift margin, in order to investigate the early development of this basin. Fault data show two trends in orientation NW–SE and NE–SW with a subordinate north–south trend. Stress inversions combined with field relationships indicate at least three phases of faulting. Firstly, an extensional event characterized by NE–SW and NW–SE normal faults, which are interpreted to have formed owing to flexural uplift in the forebulge region to the Bitlis–Zagros collisional front prior to the Middle Miocene. Secondly, north–south normal faults invert to give a stress ratio [R=(σ2 – σ3/σ1 – σ3)] indicative of an extensional stress regime, transitional to strike-slip faulting. The final stress phase (Pliocene–Recent) is of strike-slip faulting and east–west-trending normal faulting. This stress regime is interpreted as the result of the propagation of the Dead Sea Fault or East Anatolian Fault. Previous models of rift formation have invoked either transpressional or transtensional origins for the area; the new data presented here indicate that the southernmost Karasu Valley developed through extension followed by transtension.Supplementary material: The fault data (including location, orientation, kinematic information) used in this study are available at www.geolsoc.org.uk/SUP18532.

Description: The Monte Cagnero sedimentary section, which crops out in the northeastern Apennines near Urbania in the Umbria–Marche Basin (Italy), contains well-exposed strata spanning the middle Eocene to lower Oligocene interval. We use an integrated magnetobiostratigraphic approach to generate a high-resolution age model for the Monte Cagnero section, with the goal of obtaining a reliable chronostratigraphic framework for studying Eocene–Oligocene palaeoceanographic changes during the switch from greenhouse to icehouse conditions. The studied sediments consist of alternating reddish and greenish limestones and marlstones. A new integrated age model for the section is based on high-resolution palaeomagnetic analyses, combined with detailed planktonic foraminiferal and calcareous nannofossil biostratigraphic results. Rock magnetic measurements show that the magnetic mineralogy is dominated by a mixture of high- and low-coercivity minerals, probably representing a combination of hematite and magnetite. A robust magnetostratigraphic signal, together with the identification of key planktonic foraminiferal and nannofossil biostratigraphic events, allows construction of a detailed age model for the section. Based on these results, we infer that the section spans a continuous interval (within magnetochron resolution) from the middle Eocene to lower Oligocene (c. 41–27 Ma; Chrons C18r–C12r). The Monte Cagnero section, therefore, represents a sequence that is suitable for studying the impact of the Neo-Tethyan gateway closure on subtropical Eocene circulation and determining the nature and timing of palaeoceanographic changes in the Tethys through the late middle Eocene to early Oligocene interval.

Description: Euparkeria capensis has long been considered an archetype for the ancestral archosaur morphology, and has been placed just outside of crown Archosauria by nearly all cladistic analyses. Six species are currently considered to be putative members of a clade Euparkeriidae, and have been collected from Olenekian- or Anisian-aged deposits in South Africa (Euparkeria capensis – the only definitive member of the group), China (Halazhaisuchus qiaoensis, Wangisuchus tzeyii, ‘Turfanosuchus’ shageduensis), Russia (Dorosuchus neoetus) and Poland (Osmolskina czatkowicensis). Four other species (Turfanosuchus dabanensis, Xilousuchus sapingensis, Platyognathus hsui, Dongusia colorata) were historically assigned to Euparkeriidae, but have been removed by recent work. Recent authors deemed Osmolskina czatkowicensis and Dorosuchus neoetus to be the most likely taxa to form a euparkeriid clade with Euparkeria capensis, but Osmolskina czatkowicensis and Euparkeria capensis were not found as sister taxa by the only cladistic analysis to have tested euparkeriid monophyly. Euparkeria capensis was small (〈1 m), insectivorous or carnivorous, probably had vision adapted to low-light conditions and a semi-erect crocodile-like stance, and may have been facultatively bipedal. Bone histology demonstrates that Euparkeria capensis had a slow growth rate, which has been suggested to have been an adaptation to relatively stable environmental conditions.

Description: Pterosaurs are a clade of highly specialized, volant archosauromorphs recorded from the Upper Triassic to the uppermost Cretaceous. Problematic remains referred to the Pterosauria are reported from the Triassic of Europe and both North and South America, but unequivocal pterosaur specimens are only known from the Alps (Italy, Austria and Switzerland: Preondactylus buffarinii, Austriadactylus cristatus, Peteinosaurus zambellii, Eudimorphodon ranzii, Carniadactylus rosenfeldi, Caviramus schesaplanensis and Raeticodactylus filisurensis) and Greenland (‘Eudimorphodon’ cromptonellus). Pterosaurs are diagnosed mostly by features associated with the advent of powered flight. They are generally considered to be archosaurians more closely related to dinosaurs than to crocodilians, but non-archosaurian positions have also been proposed. There is a lack of general agreement about ingroup relationships, particularly among the basal pterosaurs. Triassic pterosaurs differ from other non-pterodactyloid pterosaurs in features of the dentition and caudal vertebral column. A ‘Big Bang’ model for their early history fits better with the fossil record: the earliest unequivocal pterosaurs show a sudden and geographically limited appearance in the fossil record, as well as a relatively high burst of diversity and considerable morphologic disparity. Absence of pterosaur remains from deposits where they are expected to be found suggests that they had not yet evolved in pre-Norian times.

Description: The ornithosuchids were a group of archosaurs with body lengths ranging from 2 to 4 m recorded from Upper Triassic beds in Argentina and Scotland. The group was defined as a node-based clade including Ornithosuchus longidens, Riojasuchus tenuisceps, Venaticosuchus rusconii and all descendants of their most recent common ancestor. The ornithosuchids are diagnosed by the following apomorphies observed in the three known species of the clade: downturned premaxilla; premaxilla–maxilla contact with a diastema in the alveolar margin equal in length to two teeth; palatine–pterygoid fenestra; and orbit with a distinct ventral point surrounded by ‘V’-shaped dorsal processes of the jugal. The most remarkable postcranial apomorphy of the group is the presence of the so-called crocodile reversed ankle joint, a condition that seems to be unique for the ornithosuchids among amniotans. The systematic history of Ornithosuchidae is complex and Ornithosuchus was allied with dinosaurs or phytosaurs prior to the implementation of numerical phylogenetic analyses. Currently, there is consensus that Ornithosuchidae is positioned within Pseudosuchia, but their phylogenetic position within the group remains strongly debated. Nevertheless, all hypotheses agree in inferring an extremely long ghost lineage at the base of the clade. The presence of derived pseudosuchians in the late Olenekian produces a ghost lineage of c. 16–18 millions of years for Ornithosuchidae, indicating that only the late evolutionary history of the clade is currently sampled in the fossil record.

Description: Prestosuchus chiniquensis is an extinct species of terrestrial archosaur from the Middle Triassic Epoch restricted to southern Brazil. In this paper the thigh musculature of P. chiniquensis is reconstructed based on a well-preserved specimen and on myological descriptions of extant birds and crocodylians. Among the 16 analysed muscular groups, 13 were recognized as present and homologous to both extant groups of archosaurs, and two only to the crocodylian line of archosaurs, so that 15 muscular groups were reconstructed in the fossil specimen. Morphological particularities of the pelvic girdle and the hindlimbs of P. chiniquensis gave a distinct arrangement for the muscular origin and insertion sites, leading to different lines of action and functions when compared with extant archosaurs. The comparison between extinct and extant archosaurs showed a basal condition sustained in some aspects, such as the morphology of the femur and the flexion of the knee, although other aspects were considered as derived, such as the morphology of the pubis and ischium, and their associated muscle origin locations.

Description: A small aetosaur skull and skeleton and referred material from the Chinle Formation, Eagle Basin of Colorado, USA, is described as a new taxon, Stenomyti huangae gen. et sp. nov, distinguished from other aetosaurs by the following autapomorphies: three premaxillary teeth; four palpebrals; pronounced midline ridge on frontals and parietals; paired ridges flanking midline ridge on parietal and frontal; exclusion of quadratojugal from ventral margin of skull by contact between jugal and quadrate; exclusion of postorbital from infratemporal fenestra; infratemporal fenestra a horizontally oriented oval that embays the posterior edge of the jugal; retroarticular process longer than distance between articular glenoid and posterior edge of external mandibular fenestra; oval to irregularly shaped ventral osteoderms that do not contact each other. Paramedian and lateral osteoderms of S. huangae are nearly identical to those of Aetosaurus ferratus, and other shared cranial characters suggest that these taxa are closely related and lie outside the clade Typothoracisinae + Desmatosuchinae. This discovery indicates that other reports of Aetosaurus across Laurasia based on osteoderms should be reassessed. Similar confusion with the osteoderms of other non-typothoracisine/desmatosuchine aetosaurs such as Aetosauroides, Stagonolepis and Calyptosuchus suggests that osteoderms are not always reliable taxonomic indicators.

Description: The main focus of the book is the geological and geophysical interpretation of sedimentary basins along the South, Central and North Atlantic conjugate margins, but concepts derived from physical models, outcrop analogues and present-day margins are also discussed in some chapters. There is an encompassing description of several conjugate margins worldwide, based on recent geophysical and geological datasets. An overview of important aspects related to the geodynamic development and petroleum geology of Atlantic-type sedimentary basins is also included. Several chapters analyse genetic mechanisms and break-up processes associated with rift-phase structures and salt tectonics, providing a full description of conjugate margin basins based on deep seismic profiles and potential field methods.

Description: Regional gravity data and a three-dimensional (3D) inversion approach were used to examine variations in crustal thickness and to extend seismic-based interpretations along the Scotian margin, Atlantic Canada. Constraints on Moho, crust and sedimentary layers were based on seismic refraction models and profiles of deep multichannel seismic data. A subsurface 3D density anomaly distribution was developed, using initial constraints from bathymetric data and seismic basement depth estimates, and inverting for crustal and subcrustal geometries. Predictions from the model include regional maps of Moho structure, crustal thickness and stretching factor. Depth slices allow comparison with seismic interpretations along three transects. The model predictions of variable width of crustal extension and northward thinning of oceanic crust agree with the seismic profiles. The density anomaly model shows significantly greater thinning and numerous block faulting beneath the northern margin and more uniform thinning to the SW. The fairly sharp transition between the two regions may be explained by a transfer zone separating different rifting regimes.

Description: During the complex evolution and transition of the United States (US) Central Atlantic from a rift system to a passive margin, five post-rift sedimentary depocentres developed along its approximately 1850 km length. Varying in size, shape and thickness of sediment fill, these depocentres are separated by interbasin arches and regions lacking major post-rift sedimentary depocentres.From 1976 until 1984, a single phase of exploratory drilling was carried out in three of these depocentres. Located primarily on the continental shelf, the tested play types resulted in a single, modest natural gas discovery. The drilling clarified the risks of various petroleum system elements and processes in the areas and plays tested.During 2010, a new resource inventory covering the area was completed by a team of Bureau of Ocean Energy Management geologists and engineers. The inventory incorporated and applied modern exploration concepts and key new learnings from NE-adjacent offshore Nova Scotia, conjugate NW Africa and the African transform margin. Nine new conceptual plays and a single proven high-risk play have been identified and their resources inventoried.

Description: Maps have been compiled of indicators of uplift, denudation, sedimentation rates, igneous activity and climate over South Atlantic margins in order to develop the most consistent interpretation of the development of topography, climate and sediment supply through time. Continental margin uplifts and associated topography are concentrated in the Late Cretaceous and Oligocene–Recent periods, with the rates of sediment supply from these dependent on the occurrence of wet or rapidly changing climate. An irregular bimodality is seen on several aspects of African and Brazilian margin geology through time, particularly on periods of sediment progradation, high sedimentation rates and turbidite reservoir development, with peaks of "each centred on the Santonian and Miocene. Some regions show only one of these sedimentation rate peaks and the bimodal pattern, in general, is weaker for the Brazil margin, attributed to continuing uplift of southern Brazilian margins in the early Palaeogene.A crude relationship is observed between sedimentation rate and reserves in turbidite reservoirs. Sedimentary rate mapping can thus be used to identify turbidite fairways of different ages, tied in turn to drainage catchments containing a combination of high topography and wet climate. Additional implications for source rock development and burial history are also explored.Supplementary material: The published papers and electronic sources used for the construction of sedimentation rate profiles (Excel and ArcGIS files of calculated sedimentation rates) are available at http://www.geolsoc.org.uk/gsl/SUP18520.

Description: New seismic and well data in the deep-water basins of Campos, Santos, South Kwanza and Benguela, supported by plate reconstructions, help answer fundamental questions on the rifting history of the central South Atlantic, specifically on the amount and effect of fault-related deformation, and on when and where sea-floor spreading started. The Paraná mantle plume played a fundamental role – dynamically raising the plate, prolonging continental rifting by heat-softening the crust and, after break-up, delaying the onset of marine conditions. Previous discrepancies in extension and subsidence have been solved, and the location and age of the continent–ocean boundary can now be determined. Rifting involved approximately 450 km of homogeneous pure shear, equivalent to a β factor (lithosphere stretching factor) of 4.5. Break-up occurred at 123 Ma (Barremian–Aptian boundary), 7–8 Ma later than the southern South Atlantic but 6 Ma before widespread salt deposition. The mid-Atlantic ridge was initially subaerial, marked by a volcanic high. Sea-floor spreading was at a rate of 24 mm year−1, similar to syn-rift deformation prior to break-up. Transcontinental strike-slip shear zones are not evident but a major NW–SE lithospheric lineament associated with a failed triple junction arm had a major influence on the magmatic history, both prior to and after break-up.Supplementary material: A4 versions of the seismic sections shown in Figures 6 & 7 are available at http://www.geolsoc.org.uk/SUP18563.

Description: The Nova Scotia and Morocco margins formed within a transition between volcanic margins to the south and non-volcanic margins to the north. We present deep seismic profiles to document the nature of this transition. Profiles on the Nova Scotia margin show two major transitions. The first transition represents a sharp reduction in syn-rift volcanism coincident with major changes in the East Coast Magnetic Anomaly and with the southern limit of the Slope Diapiric Province. The second transition represents a further restriction in syn- and post-rift volcanism leading to exposure of serpentinized mantle or the creation of highly tectonized oceanic crust. This transition is marked by highly extended and faulted continental crustal blocks. Revised plate reconstructions show similar transitions along the Moroccan margin. The southern transition occurs at a major change in the West Africa Coast Magnetic Anomaly and the southern limit of the Morocco Salt Basin. The second transition occurs at a major basement high (Tafelney Plateau), which is considered a high relief accommodation zone and contains highly extended faulted crustal blocks similar to those in a conjugate position off central Nova Scotia. This transition marks a major change in rifting asymmetry and separates the margins into two fundamentally distinct segments.

Description: Understanding the genesis of the very peculiar 600 km-wide Santos Basin–São Paulo Plateau system and its narrow conjugate Namibe Margin is a kinematic and structural problem. Several hypotheses have been proposed in order to explain the genesis of this system that imply the same amount of horizontal movement. We investigate the consequences of the horizontal movement in the Santos Basin, based in plate kinematic reconstructions. The kinematic history of this system that we present here, based on the interpretation of seismic profiles and kinematic constraints, has the following consequences: (1) there is no evidence of a ridge jump sensu stricto but, rather, a southwards propagation in the Central Segment of the South Atlantic that starts in the northern part, between the NE Brazilian and Gabonese margins; (2) the Namibe margin evolved as a transform passive margin; (3) the opening direction of the Santos Basin–São Paulo Plateau system is oblique to the general opening motions of the South American and African plates; and (4) this opening is younger (6 Ma) than those of the other basins of the Central Segment of the South Atlantic.

Description: The Moroccan salt basin appears to be very unique in the sense that it is not sedimentary loading but tectonic inversion which appears to drive the latest stages of salt-related deformation in the central part of the basin. The gravity potential to maintain salt tectonics is provided by the differential uplift of the Atlas Mountains, located adjacent and striking almost perpendicular to the margin.Along the offshore part of the Moroccan salt basin there are many play types, most of them related to the Triassic syn-rift salt. Toe-thrust anticlines at the basinwards edge of the salt basin form very large structures. Traps associated with salt tongues and diapirs define a more ‘classical’ salt-flank play. Numerous salt tongues, sheets and canopy complexes provide for a ‘Gulf of Mexico-style’ subsalt play. Despite the numerous untested play types, there have been only four deep-water exploration wells drilled in the entire Moroccan salt basin, none of them having subsalt penetrations.

Description: Tectonic reconstructions made across the southern South Atlantic Ocean indicate a diversity of rift and drift basin characteristics on the conjugate margins that define them as different stratigraphic and structural entities. In terms of petroleum systems, the basins are not as unlike as some characteristics suggest. Given the lack of significant hydrocarbon discoveries to date south of the Walvis Ridge, doubts have been cast on the presence in this area of the prolific Lower Cretaceous lacustrine and marine source rock systems, which are well known in the Greater Campos Basin and offshore Angola. Oils and condensates from the basins south and north of the Walvis Ridge exhibit geochemical similarities suggesting that comparable source rock systems are present in both areas. The condensate geochemical analysis results from the Kudu Field in Namibia are compared with oils from marine and lacustrine sources in Brazil, indicating that the Kudu condensates are derived from at least two different source rocks. These results suggest that the underexplored basins offshore Namibia contain thermally mature Lower Cretaceous lacustrine and marine source rocks, offering a new frontier for petroleum exploration in Africa's southern South Atlantic.

Description: The study focuses on Equatorial Atlantic margins, and draws from seismic, well, gravimetric and magnetic data combined with thermo-mechanical numerical modelling.Our data and numerical modelling indicates that early drift along strike-slip-originated margins is frequently characterized by up to 10°–20° spreading vector adjustments. In combination with the warm, thinned crust of the continental margin, these adjustments control localized transpression.Our observations indicate that early-drift margin slopes are too steep to hold sedimentary cover, which results in their inability to develop a moderately steep slope undergoing cycles of gravitational instability resulting in cyclic gravity gliding. These slopes either never develop such conditions or gain them at later development stages.Our modelling suggests that the continental margin undergoing strike-slip-controlled break-up experiences warming due to thinning along pull-apart basin systems. Pull-apart basins eventually develop sea-floor spreading ridges. Margins bounded by strike-slip faults located among pull-apart basins with these ridges first undergo cooling. However, spreading ridges leaving the break-up trace along its strike eventually pass by these cooling margins, warming them again before the final cooling proceeds. As a result, the structural highs surrounded by several source rock kitchens witness a sequential expulsion onset in different kitchens along the trajectory of spreading ridges.Supplementary material: Discussion of the methods used, chronostratigraphic results and strike-slip margin characteristics are available at http://www.geolsoc.org.uk/SUP18518

Description: Reconstructions of the Anatolian continent and adjacent areas assume the existence of one or more continental fragments during Mesozoic–Early Cenozoic time. These rifted from North Africa (Gondwana) during the Triassic, drifted across the Mesozoic Tethys and collided with Eurasia during latest Cretaceous–Paleocene time. Current reconstructions range from a regional-scale Tauride–Anatolide continent with oceanic basins to the north and south, to numerous rifted continental fragments separated by small oceanic basins. Field-based evidence for the inter-relations of the continental blocks and associated carbonate platforms is discussed and evaluated here, especially to distinguish between sutured oceans and intra-continental convergence zones. Several crustal units are restored as different parts of one large Tauride–Anatolide continent, whereas several smaller crustal units (e.g. Kırşehir massif; Bitlis/Pütürge and Alanya/Kyrenia units) are interpreted as continental fragments bordered by oceanic crust. We infer a relatively wide İzmir–Ankara–Erzincan ocean in the north and also a wide South Neotethyan ocean in the south. Several smaller oceanic strands (e.g. Inner Tauride ocean, Berit ocean and Alanya ocean) were separated by continental fragments. Our proposed reconstructions are shown on palaeotectonic maps for Late Permian to Mid-Miocene. The reconstructions have interesting implications for crustal processes, including ophiolite genesis and emplacement.

Description: Magnetostratigraphy is best known as a technique that employs correlation among different stratigraphic sections using the magnetic directions defining geomagnetic polarity reversals as marker horizons. The ages of the polarity reversals provide common tie points among the sections, allowing accurate time correlation. Recently, studies of magnetic methods and the timing of geological processes have acquired a broader meaning, now referring to many types of magnetic measurements within a stratigraphic sequence. Many of these measurements provide correlation and age control not only for the older and younger boundaries of a polarity interval, but also within intervals. Thus, magnetostratigraphy no longer represents a dating tool based only on geomagnetic polarity reversals, but comprises a set of techniques that includes measurements of geomagnetic field parameters, environmental magnetism, rock-magnetic properties, radiometric dating and astronomically forced palaeoclimatic change recorded in sedimentary rocks, and key corrections to magnetic directions related to geodynamics, palaeocurrents, tectonics and diagenetic processes.

Description: The nature of the southern margin of the Anatolian microplate during the Neogene is complex, controversial and fundamental in understanding active plate-margin tectonics and natural hazards in the Eastern Mediterranean region. Our investigation provides new insights into the Late Pleistocene uplift history of Cyprus and the Troodos Ophiolite. We provide isotopic (14C) and radiogenic (luminescence) dates of outcropping marine sediments in eastern Cyprus that identify periods of deposition during marine isotope stages (MIS) 3, 4, 5 and 6. Past sea-levels indicated by these deposits are c. 95±25 m higher in elevation than estimates of worldwide eustatic sea-level. An uplift rate of c. 1.8 mm/year and possibly as much as c. 4.1 mm/year in the past c. 26–40 ka is indicated. Holocene marine deposits also occur at elevations higher than those expected for past SL and suggest uplift rates of c. 1.2–2.1 mm/year. MIS-3 marine deposits that crop out in southern and western Cyprus indicate uniform island-wide uplift. We propose a model of tectonic wedging at a plate-bounding restraining bend as a mechanism for Late Pleistocene to Holocene uplift of Cyprus; uplift is accommodated by deformation and seismicity along the margins of the Troodos Ophiolite and re-activation of its low-angle, basal shear zone.Supplementary material: An expanded description of the procedures used in determining OSL ages for samples given in Table 2 is available at www.geolsoc.org.uk/SUP18533.

Description: Magnetostratigraphy is best known as a technique that employs correlation among different stratigraphic sections using the magnetic directions that define geomagnetic polarity reversals as marker-horizons. The ages of the polarity reversals provide common tie points among the sections, allowing accurate time correlation. Recently, magnetostratigraphy has acquired a broader meaning, now referring to many types of magnetic measurements within a stratigraphic sequence. Many of these measurements provide correlation and age control not only for the older and younger boundaries of a polarity interval, but also within intervals. Thus, magnetostratigraphy no longer represents a dating tool based only on the geomagnetic polarity reversals, but comprises a set of techniques that includes measurements of all geomagnetic field parameters, environmental magnetism, rock magnetic and palaeoclimatic change recorded in sedimentary rocks, and key corrections to magnetic directions related to geodynamics, tectonics and diagenetic processes.

Description: Lower Eocene to Oligocene microfossil-rich hemipelagic sediments in ODP Hole 647A, southern Labrador Sea, provide a strategic section for resolving the early history of high North Atlantic climates and ocean circulation, and for correlating with carbonate-poor lower Cenozoic sediments in the Arctic and Nordic seas. Our new, integrated palaeomagneto- and multigroup biostratigraphy (63 dinoflagellate cyst, calcareous nannofossil, planktonic foraminifer and diatom datums) significantly improves Site 647 chronostratigraphy and provides a framework for future studies. This new age model, coupled with provisional δ18O analyses, provides greater confidence in the location of significant ocean-climate events at this site, including the Eocene–Oligocene transition and the Middle Eocene Climatic Optimum. Early Eocene hyperthermals may also be present near the base of the section. Palaeomagnetic age control is significantly improved in the Eocene, but not in the Oligocene. Revised estimates of sedimentation and biogenic flux indicate changes in supply and preservation that may be climatically controlled. A Lower to Middle Eocene hiatus is more precisely constrained, with a c. 4 million year duration. Age and depth errors quantify the age uncertainties throughout the section. Our revised age model will play an important role in stratigraphic correlation between very high latitude and lower latitude sites.Supplementary material: All tables with ages and age-derived calculations based on the Gradstein et al. (2004) timescale used herein are reproduced as supplementary tables using both the Gradstein et al. (2004) and the Cande & Kent (1995) timescales (Tables DS1–DS6). Discrete sample and shipboard pass-through cryomagnetometer palaeomagnetic data, planktonic foraminifer and fine fraction (〈20 µm) stable isotope data, raw and processed core GRA density data, and specifications and results of GRA density spectral analyses are also provided as supplementary tables (Tables DS7–DS11). These tables are available at www.geolsoc.org.uk/SUP18546.

Description: Correlation of lithostratigraphic sections is widely used to examine the nature of lateral facies changes within or between basins. It can provide significant clues for regional environmental and palaeogeographic reconstructions. There are problems associated with lithostratigraphic correlation; diachronous deposition of similar lithological units may not be recognized. We report here an attempt to determine lateral facies changes in coeval sedimentary sections, through three-dimensional magnetostratigraphic correlations in the Guide Basin, an intramontane basin in the northeastern part of the Tibetan Plateau. The method is successful for correlating lateral facies and helps to identify sediment sources in the basin.

Description: We conducted a palaeomagnetic study on the Cenozoic sedimentary sequences of the Nankai Trough, recovered by the Integrated Ocean Drilling Program Expedition 322 in SE Japan. Sedimentary sections of Late Miocene age from the two subduction input sites (sites C0011 and C0012) recorded a pattern of magnetic polarity reversals that correlates well with the known magnetic polarity time scale. The polarity of characteristic remanent magnetization could be identified throughout the majority of the recovered cores of the two sites, following removal of a low-stability drilling-induced remanence. Most of the observed magnetostratigraphy from the characteristic directions is in good agreement with that to be expected from the stratigraphic position of the sequence deduced from the biostratigraphic data. Palaeomagnetic data from both shipboard and shore-based studies indicate changes in the rate of sedimentation from 9.5 to 2.7 cm/kyr at about 11 Ma, suggesting that some fundamental palaeoenvironmental change in the Shikoku Basin and/or significant tectonic event may have occurred in Late Miocene.

Description: Extensive outcrops in the Umbria–Marche Basin of central Italy include some of the most complete successions of Palaeogene sediments known from the Tethyan Realm. Owing to the continuous deposition in a pelagic setting, a rather modest tectonic overprint, the availability of excellent age control through magneto-, bio-, chemo- and tephrostratigraphy, and direct radioisotopic dates from interbedded volcaniclastic layers, these sediments have played a prominent role in the establishment of standard Palaeogene time scales. We present here a complete and well-preserved Palaeogene pelagic composite succession of the Umbria–Marche Basin, which provides the means for an accurate and precise calibration of the Palaeogene time scale. As a necessary step towards the compilation of a more robust database on a wide scale so as to improve the magneto-, bio- and chronostratigraphic framework of the classical southern Tethyan zonations, enabling regional and supraregional correlations, we have constructed a record of reliable Palaeogene planktonic foraminifera, calcareous nannofossil and dinocyst biohorizons commonly used in tropical to subtropical Cenozoic zonations. In addition, an age model is provided for the Palaeogene pelagic composite succession based on magnetostratigraphy, planktonic foraminifera and calcareous nannofossils, which contributes to an integrated chronology for the Palaeogene Tethyan sediments from c. 65.5 to 23 Ma.Supplementary material: Tables 1 to 13 which provide further details of the Palaeogene pelagic succession of the Umbria–Marche Basin (central Italy) are available at http://www.geolsoc.org.uk/SUP18539

Description: Ocean Drilling Program (ODP) Site 711, located in the western equatorial Indian Ocean near the Seychelles Archipelago on Madingley Rise, is an important site for studying middle Eocene to early Oligocene climatic evolution. This site is ideal for studying the impact of Neo-Tethyan gateway closure on Indian Ocean currents and circulation to further understand global climate changes through the greenhouse to icehouse transition. Middle Eocene-to-lower Oligocene strata recovered within Hole 711A (Cores 711A-14X to 21X) primarily consist of clay-bearing nannofossil oozes/chalks, with layers rich in radiolarians. Here, we report a high-resolution magnetostratigraphic record and a new integrated age model for the middle Eocene-to-lower Oligocene section of Hole 711A. Correlation of the polarity pattern to the geomagnetic polarity timescale provides a record from Chron C19r (middle Eocene) to C12r (early Oligocene). Our results extend the existing polarity record down into the middle Eocene and confirm published results from the lower Oligocene section of the hole. Overall, these new results from Hole 711A have important implications for identifying and dating global climate change events, and for reconstructing calcite compensation depth history at this site.Supplementary material: Magnetostratigraphic data used for construction of age models for Hole 711A included in this study are available at: www.geolsoc.org.uk/SUP18595

Description: We studied the detailed characteristics of the Pringle Falls excursion from samples at the original site recovered from four profiles drilled along the Deschutes River, Oregon. We drilled 827 samples spaced along 5 km for their detailed directional study. The profiles registered a high-resolution (〉10 cm/ka) palaeomagnetic record of the excursion (c. 211±13 ka) recorded by diatomaceous lacustrine sediments. We conducted palaeomagnetic and rock magnetic studies to investigate the reproducibility of the signal throughout the profiles. We performed low-field susceptibility v. temperature analysis that indicated that the main magnetic carrier is pure magnetite (Curie point 575 °C). The magnetic grain size also indicated single domain–multi domain (SD–MD) magnetite. The demagnetization was performed by alternating field experiments and the mean directions were determined by principal component analyses. The detailed behaviour of the palaeosignal is highly consistent since they are rapidly deposited sediments providing a detailed representation of the palaeofield. The dissected virtual geomagnetic pole paths in three different phases are highly internally consistent and are defined by clockwise and anticlockwise loops travelling from high northern latitudes over eastern North America and the North Atlantic to South America and then to high southern latitudes; then they return to high northern latitudes through the Pacific and over to Kamchatka.

Description: Non-crocodyliform crocodylomorphs, often called ‘sphenosuchians’, were the earliest-diverging lineages of Crocodylomorpha, and document the stepwise acquisition of many of the features that characterize extant crocodylians. The first crocodylomorph fossils are approximately 230 million years old (upper Carnian, Late Triassic), and at least one of these early lineages persisted until at least 150 million years ago (Late Jurassic). These taxa occupied a wide variety of terrestrial environments from equatorial regions to high-paleolatitudes during the early Mesozoic. Despite a quarter-century of quantitative phylogenetic work, the interrelationships of early crocodylomorphs remain in a state of flux, though recent studies suggest that these lineages are paraphyletic with respect to Crocodyliformes, rather than forming a monophyletic early offshoot of Crocodylomorpha as some previously hypothesized. Nearly all early crocodylomorphs were upright quadrupedal small-bodied taxa, but lumping them all together as small cursorial faunivores masks ecological and morphological disparity in diet and limb functional morphology. With the accelerated pace of recent discovery of new specimens and taxa, future consensus on early crocodylomorph phylogeny will provide a solid framework for understanding their change in diversity and disparity through time, potential biogeographic patterns, and the morphological transformation leading to Crocodyliformes.

Description: Recent palaeohistological studies on paramedian osteoderms of aetosaurs revealed the presence of growth lines (lines of arrested growth or LAGs) and a minimal or nonexistent secondary remodelling in the bone matrix of these elements. This feature allows the age of individuals to be estimated through growth line count. In the present contribution we study the growth curve of the South American aetosaur Aetosauroides scagliai. We estimated the age (obtained from LAG counting) and body size (body length and body mass were used as proxies) of different aetosaur specimens in order to reconstruct the growth curve of the South American species. The data obtained for Aetosauroides scagliai were compared with that of other aetosaurs, such as Neoaetosauroides engaeus, Aetosaurus ferratus, Aetobarbakinoides brasiliensis, Typothorax coccinarum and Paratypothorax sp. Our results indicate that, if body length is considered as proxy, all studied aetosaur specimens have a similar or almost identical growth rate. However, important variations arose among aetosaur taxa if body mass is considered as proxy, which would be related to a body morphology ranging from slender (e.g. Aetobarbakinoides brasiliensis) to very wide (Typothorax coccinarum) morphotypes. In comparison with extant pseudosuchians (i.e. crocodylians), Aetosauroides scagliai possesses a relatively lower growth rate.

Description: Unlike most rauisuchians, which are known based on partially preserved specimens, fossils attributed to Decuriasuchus quartacolonia include a monotaxonomic assemblage composed of nine associated individuals (MCN-PV10.105a–i), three with almost complete skulls (MCN-PV10.105a,c,d), and a partial disarticulated skull (MCN-PV10.004) collected in the Middle Triassic (Ladinian, Dinodontosaurus Biozone) beds of the Santa Maria Formation, in south Brazil. Because of its completeness and possible phylogenetic position, as one of the most basal loricatans, D. quartacolonia is a key taxon for anatomic, evolutionary and biomechanical studies of rauisuchians. The comparative description of its osteology reveals that the skull and mandible of D. quartacolonia are very similar to those of cf. Prestosuchus chiniquensis and Saurosuchus galilei, sharing a drop-shaped subnarial fenestra, a subtriangular antorbital fenestra with an elongated and narrow anterior point, a ‘roman nosed’ nasal, and a posteroventrally oriented ridge on the lateral surface of the ventral ramus of the squamosal. Among the differences are the autapomorphies of D. quartacolonia: numerous maxillary teeth (17), lateral expansion of the nasal/lacrimal covering the antorbital fenestra dorsally, and squamosal and quadratojugal forming a subtriangular projection that invades the lower temporal fenestra.

Description: A palaeogeographical reconstruction of the South American and African continents back to anomaly C34 (84 Ma) brings together the Rio Grande Rise (RGR) and the central portion of the Walvis Ridge (WR), thus the RGR–WR aseismic ridges may have a common origin. If the construction of the RGR–WR basaltic plateau took place mainly between 89 and 78 Ma, as indicated by the ages of the basalts sampled by DSDP wells, then the basaltic magmas are the result of an ‘on-ridge’ volcanism. Once separated, the normal sea-floor spreading and thermal subsidence of the RGR and WR ridges continued until approximately 47 Ma when an Eocene magmatism took place in the RGR. In the WR, a younger volcanism is observed in the Guyot Province. The available geochemical and isotope data of the WR–RGR basalts do not indicate the participation of the continental crust melting component. Incompatible trace element ratios and isotope signatures of the basalts from the RGR–WR ridges are distinct from the present-day Tristan da Cunha alkaline rocks, and are nearly identical to the high-Ti Paraná Magmatic Province (PMP) tholeiites (133–132 Ma). Both the high-Ti PMP and the WR–RGR basalts are characterized by moderate initial 87Sr/86Sr and low 206Pb/204Pb isotope ratios [Enriched Mantle I (EMI) mantle component], suggesting melting from a common source, with significant participation of sub-continental lithospheric mantle (SCLM). A three-dimensional (3D) flexural modelling of the RGR and WR was conducted using ETOPO1 digital topography/bathymetry and EGM2008-derived free-air anomalies as a constraint. The best fit between the observed and calculated free-air anomalies was obtained for an elastic plate with elastic plate thickness (Te) of less than 5 km, consistent with an ‘on-ridge’ initial construction of the RGR–WR. The modelling of the crust–mantle interface depths indicates a total crustal thickness of up to 30 km in the RGR–WR. Flexural analysis reinforces the geological evidence that RGR was constructed during two main magmatic episodes, the tholeiitic basalts in the Santonian–Conician times and the alkaline magmatism in the Eocene. Geochemical and geophysical evidence, which rules out the classical deep-mantle plume model in explaining the generation of basalts of these volcanic provinces, is presented. Finally, three models to explain the geochemical and isotope signatures of RGR–WR basalts are reviewed: (1) thermal erosion of SCLM owing to edge-driven convection; (2) melting of fragmented or detached SCLM and lower crust; and (3) thermal erosion at the base of the SCLM with lateral transport of enriched components by mantle flow.

Description: The first comprehensive geological and geophysical surveys of the Brazilian continental margin during the 1970s recognized the crust in the SE Brazilian basins as ‘anomalous’ but models for the opening of the South Atlantic proposed at that time invoked a very narrow continent–ocean transition. Nevertheless, such studies established the presence of a thick sedimentary prism, including an extensive salt layer under the São Paulo Plateau. The earliest reconstructions for the South Atlantic invoked a seaward shift of the spreading axis to account for the asymmetric widths of the salt layer between the Brazilian margin and its conjugate in offshore Africa.Although our understanding of continent–ocean transition has progressed since then, direct seismic imaging at crustal scale has only been possible recently through long offset (10 km), deep recording (18 s), pre-stack depth migrated (PSDM) to 40 km, seismic-reflection data. These data allow us to generally image the Moho from under thick continental crust (〉30 km) to thin oceanic crust (c. 5 km). Although the nature of the transitional crust is still contested, these seismic data allow for constraints on various models for continent–ocean transition. Future integrated studies utilizing PSDM and refraction-seismic data will further refine these models.

Description: The discovery of the Jubilee Oil Field in 2007 in the Tano Basin of Ghana is a primary example of the potential for Late Cretaceous deep-water stratigraphic traps in basins previously overlooked by the exploration industry. The Tano Basin forms the eastern extension of the Deep Ivorian Basin, which resulted from Aptian–Albian trans-tension associated with the opening of the Atlantic between the St Paul and Romanche fracture zones and the subsequent post-rift subsidence. The basin was the focus for deposition of a thick Upper Cretaceous, deep-water clastic sequence, which, in combination with a modest Tertiary section, provided sufficient thickness to mature a Cretaceous source rock in the central part of the Tano Basin. This well-defined reservoir and charge fairway forms the play, which, when draped over a large plunging nose (the South Tano high), resulted in the formation of a stratigraphic–structural combination trapping geometry that is characteristic of the Jubilee Field and subsequent discoveries in this play.

Description: The Almada Basin, located in the southern Bahia State segment of NE Brazil, shares a similar sedimentation history and stress regime with the other eastern Brazilian basins. But when considering the composition of the transitional crust, a remarkably different behaviour is observed between the Almada Basin and the other eastern Brazilian basins. The architectural elements of the basin such as the reflection Moho discontinuity, the oceanic and continental basements, and the sedimentary section, as well as the tectonic style, are discussed in this study using gravity, seismic, regional geology and well-drilling results.The Almada Basin is part of a continental rift system that developed during the Early Cretaceous, heralding the Gondwana break-up and subsequently evolving into a passive divergent margin. Deep seismic profiles show the progressive thinning of the continental crust but there is no clear evidence of mantle exhumation.The Almada Basin is the conjugate margin of the South Gabon Basin in West Africa. Although both basins display similar stratigraphic record and geological evolution, the rifting mechanism resulted in a considerable asymmetric break-up. The Almada Basin is floored by the Itabunas–Salvador–Curaçá Belt of the São Francisco Craton and is characterized by Palaeoproterozoic granulites in a high-angle east-dipping thrust fault regime. However, the South Gabon Basin lies on the Neoproterozoic West Congolian Belt that is made up of low- to medium-grade metamorphic rocks in a low-angle thrust tectonic regime. The Precambrian basement fabric of both the Almada and South Gabon basins is marked by lithospheric-scale discontinuities that controlled the implantation of the rift zone and the extension style during the Mesozoic. The strong basement structural inheritance can be recognized in both the geological and geophysical records.The key architectural elements of a volcanic margin, such as large igneous provinces, seaward-dipping reflectors and the basinal syn-rift magmatism, are not recognized in the Almada Basin. Although the South Atlantic margin is mostly volcanic in the southernmost segment, the presence of these two non-volcanic segments – the southern Bahia State and the southern Gabon – are important as a record of the differences in the geotectonic process that governed the formation of the South Atlantic divergent margins.

Description: We use seismic, field, core, borehole and vitrinite-reflectance data to constrain the development of the Newark Rift Basin, one of the largest and most thoroughly studied basins of the eastern North American rift system that formed during the break-up of Pangaea. These data provide critical information about the geometry of the preserved synrift section and the magnitude of post-rift erosion. We incorporate this information into a new structural restoration of the basin. Our work shows that the Newark Basin was initially narrow (〈25 km) and markedly asymmetric; synrift strata show significant thickening towards the basin-bounding faults. Subsequently, the basin became wider (perhaps 〉100 km wide), deeper (up to 10 km) and less asymmetric; synrift strata exhibit subtle thickening towards the basin-bounding fault system. Several intrabasin faults dissected the Newark Basin after synrift deposition, and the basin fill was tilted (c. 10°NW) and folded. Erosion (up to 6 km) accompanied the intrabasin faulting, NW tilting and folding, significantly reducing the basin size. Our work suggests that the eastern North American rift system is characterized by a very broad zone of upper-crustal extension in which a few, wide, deep, long-lived, fault-bounded basins (like the Newark Basin) accommodated much of the extension.

Description: Deposition of the Abenaki Formation carbonate complex began during the Middle Jurassic, shortly after the interpreted onset of western Atlantic sea-floor spreading, and continued through Late Jurassic time, resulting in thick carbonate deposits along the Jurassic shelf edge. This carbonate complex was the exploration target of 16 wells drilled from 1970 to 1989. Although there were no discoveries in the carbonate objectives, oil was discovered in Cretaceous siliciclastics in structural drape closures overlying the carbonate margin.The Province of Nova Scotia decided to undertake a technical study to further the interest in the carbonate bank objective while the shallow oil play was being developed. Subsequently, in 1989, two studies were undertaken to investigate a porosity play in the Jurassic Baccaro Member of the Abenaki Formation because significant porosity had been encountered in a number of the dry holes that targeted the carbonate margin, particularly the Demascota G-32 well.The first study modelled porosity in several wells utilizing one-dimensional (1D) and wedge models, and amplitude v. offset (AVO) models. The Demascota G-32 well was used to seismically identify and model several types of potential hydrocarbon-bearing prospects along the bank. Modelling indicated that zones of 11–14% porosity with a minimum thickness of 10 m could be detected. However, a thickness of 50 m was required to resolve the top and base of the porosity. The AVO model for the Demascota well demonstrated that an increase in amplitude with offset (AVO effect) in the presence of gas and fracturing (which dramatically decreases Poisson’s ratio) should be detectable and may be useful in identifying prospects in this type of play. The assumption of a fractured reservoir was reasonable due to the number of seismically identified faults at the front of the carbonate bank and the description of fractures in conventional cores taken in the Baccaro Member. The second study involved acquiring a pair of dip and strike seismic lines adjacent to the Demascota well and reprocessing them to preserve relative amplitudes while providing a high-resolution, stacked section, especially at the Baccaro Member level. Interpretation of these lines was undertaken in the AVO domain. An increase in amplitude with offset was observed up-dip of the Demascota G-32 well that indicated a fractured, gas-filled porous zone could exist up-dip of this well.Following these studies, 3D seismic data was acquired over the shallower Panuke Oil Field and similar studies were conducted on that dataset in 1997. As a result, Encana drilled a structural high containing bright amplitude reflectors and encountered over 100 m of net gas pay in vuggy and cavernous limestones and dolomites in 1999. This validated the earlier studies, confirming that these reservoirs could be seen on seismic data and proved that economic gas reservoirs exist in the carbonate bank. These results should encourage exploration along the extensive, sparsely drilled Late Jurassic carbonate margins bounding offshore eastern North America and its conjugates in the Central Atlantic Region.

Description: The tectonosedimentary development of the South Atlantic is compared with the Central Atlantic margins, which are associated with major episodes of magmatism during the Mesozoic continental break-up. Subsequently, the Cenozoic break-up in the North Atlantic led to the formation of the volcanic Norwegian–Greenland conjugate margins. The DSDP boreholes in the magma-poor Iberian–Newfoundland margins have confirmed the occurrence of exhumed mantle at the ocean–continent transition. This possibility has been suggested for the South Atlantic margins, but still lacks confirmation from drilling.The Red Sea and the Gulf of Aden may be considered as natural laboratories to study the break-up processes and formation of divergent continental margins. Using key geological and geophysical data, we compare some of the structures observed in incipient stages of basin formation between the African and the Arabian plates with the structures observed in older sedimentary basins associated with the Gondwana break-up. We also analyse deep seismic reflection profiles and potential field data at the continent–ocean boundary of these conjugate margins, using palinspastic reconstructions to define the corresponding seismic pairs. We conclude that the Red Sea and the Gulf of Aden display remarkable differences to the Iberian–Newfoundland margins, and notable similarities with the South Atlantic margins.

Description: The segmented East Indian continental margin developed after the Early Cretaceous break-up from Antarctica. Its continental crust terminates abruptly without considerable thinning along the Coromondal strike-slip segment and thins considerably before it terminates in the orthogonal rifting segments. The segments have an exhumed continental mantle corridor oceanwards of them. This, proto-oceanic crust, corridor varies in width from segment to segment, indicating a relationship with varying break-up-controlling tectonics of the adjacent margin segments.The top of the proto-oceanic crust is imaged by a higher reflectivity zone, while its base does not have any distinct signature. A contorted system of reflectors represents its internal structure. Its gravity signature is a longer-wavelength anomaly with peak values up to 30 mGal less negative than surrounding values. Its magnetic signature is represented by a positive anomaly with peak values of 0–56 nT. Wide proto-oceanic segments are adjacent to margin segments that are preceded by the orthogonally rifting Cauvery, Krishna–Godavari and Mahanadi rift zones. A narrow proto-oceanic segment is adjacent to the margin segment initiated by the dextral Coromondal transfer zone. A combination of seismic interpretation and gravity/magnetic forward modelling indicates that proto-oceanic crust is most probably composed of lower crust slivers and unroofed hydrated upper mantle, being formed between the late rifting and the organized sea-floor spreading.

Description: Two different types of ‘transitional lithosphere’ have been documented along magma-poor rifted margins. One consists of apparently subcontinental mantle that has been exhumed, brittlely deformed, and serpentinized during late stages of rifting. A second is thinned (〈10 km) continental crust, which in some cases is known to have been supported near sea level at least early in the rift history and thus is interpreted to reflect depth-dependent extension. In both cases, it is typically assumed that oceanic crust forms at the time that the brittle continental crust is breached or soon thereafter, and thus that transitional lithosphere has relatively limited width. Here three representative cases of transitional lithosphere are examined: one in the Newfoundland–Iberia rift and one at Goban Spur (both exhumed mantle), and one off the Angola–Congo margin (thin continental crust flanked seaward by apparently exhumed lower continental crust±exhumed mantle). Considering the geological and geophysical evidence, it appears that depth-dependent extension (riftward flow of weak lower continental crust and/or upper mantle) may be a common phenomenon on magma-poor margins and that this can result in a much broader zone of transitional lithosphere than has hitherto been assumed. Transitional lithosphere in this wide zone may consist of subcontinental mantle, lower continental crust or some combination thereof, depending on the strength profile of the pre-rift continental lithosphere. Transitional lithosphere ceases to be emplaced (i.e. ‘final break-up’ occurs) only when emplacement of heat and melt from the rising asthenosphere becomes dominant over lateral flow of the weak lower lithosphere. This model implies a two-stage break-up: first, the rupture of the brittle continental crust; and, second, the eventual separation of the ductile subcontinental lithosphere which is coincident with emplacement of normal oceanic crust. Well defined magnetic anomalies can form in transitional lithosphere that consists of highly serpentinized, exhumed mantle, and such anomalies therefore are not diagnostic of oceanic crust. Where present, the anomalies can be helpful in interpreting and dating the rifting history.

Description: Middle Eocene magmatic rocks (MEMR) (49.3±2 to 38.1±1.9 Ma) formed an east–west trending belt after continental collision and rest unconformably on pre-Middle Eocene units as a common cover. The origin and tectonic setting of MEMR are controversial as both arc and post-collisional settings are proposed. We present new geological and petrological data from the western part of the belt, between the Armutlu Peninsula and the Almacık Mountains. The MEMR are represented by basic to intermediate volcanic rocks, dykes and coeval granites. The lavas exhibit a continuous trend from basalt to dacite. The MEMR as a whole display low- to medium-K subalkaline (to rarely mildly alkaline) affinities and a calc-alkaline trend. On N-type Mid Ocean Ridge Basalt-normalized spidergrams these rocks display relative enrichment in large ion lithophile elements, slight enrichment in light rare earth elements, but depletion in Ta and Nb. Geochemical data and Sr, Nd, Pb and δ18O isotope compositions, coupled with εNd(T) values, reveal that the MEMR magma was of hybrid type, with both depleted sub-continental lithospheric mantle and crustal components. We conclude that the MEMR was produced in a post-collisional setting, and we favour a slab-breakoff mechanism to explain this as it is consistent with the known Middle Eocene tectonic evolution of northwestern Turkey.

Description: Evidence mainly from Neogene–Recent sedimentary units and penetrative structures (faults and folds) is used to constrain stress regimes in Cyprus. Following c. south-vergent folding/thrusting, a regional change to extension activated several depocentres during the Late Miocene–Early Pliocene. Fault analysis establishes that kinematic linkages existed between the four Late Miocene basins in southern and western Cyprus. During Late Pliocene(?)–Early Pleistocene time there was a switch to c. east–west left-lateral strike-slip/transpression and fault reactivation. Late Pleistocene growth folding in western coastal Cyprus is explained by reactivation of extensional faults in a left-lateral stress regime. The timing of neotectonic faulting/folding in several areas is constrained by optically stimulated luminescence dating. Existing tectonic models involving north–south collision, left-lateral strike-slip and post-collisional suture tightening are problematic in certain respects. A new model is proposed in which Late Miocene extensional basin formation relates to northward subduction coupled with rollback of the African plate. Subduction culminated in collision of the Eratosthenes Seamount, the leading edge of the African plate, with the Cyprus active margin (c. 3 Ma). This initiated regional uplift focused on the Troodos Massif. Cyprus was by then coupled with Anatolia as it escaped westwards towards the Aegean subduction zone, giving rise to dominantly strike-slip-related structures in southern Cyprus during the Late Pliocene–Recent.

Description: Anatolia and the easternmost Mediterranean region, especially Turkey, Cyprus and northern Syria, represent an excellent natural laboratory for the study of fundamental geological processes (e.g. rifting, seafloor spreading, ophiolite genesis and emplacement, subduction, exhumation and collision). Their interaction has created an intriguing array of deep-sea basins, microcontinents and suture zones.The volume's 22 papers include a large amount of new field-based information (much of it multidisciplinary and the product of teamwork). After an overview, the volume is divided into four sections: Late Palaeozoic–Early Cenozoic of the Pontides (northern Turkey); Late Palaeozoic–Early Cenozoic of the Taurides–Anatolides (central and southern Turkey); Late Cretaceous–Pliocene sedimentary basins and structural development (central Anatolia to the Mediterranean); Late Miocene–Recent Neotectonics (southern Turkey, Cyprus and northern Syria).The volume will interest numerous academic researchers, those concerned with resources (e.g. hydrocarbons; mineral deposits) and also hazards (e.g. earthquakes), as well as advanced undergraduate and postgraduate students.

Description: Upper Ordovician–Upper Cretaceous high-pressure–low-temperature metasedimentary and meta-igneous rocks in the Dursunbey area provide insights into the Tavşanlı Zone (Anatolides) when compared to crustal units further south (e.g. Afyon Zone and Taurides). Schists near the base of the Tavşanlı Zone succession are cut by a small Upper Ordovician metagranite. This is covered by metaclastic sediments that are interbedded with bimodal rift-related basic-silicic volcanics of inferred Triassic age. Above this is a thick metacarbonate platform interpreted as the result of post-rift subsidence. Overlying metacarbonates, metapelites and metachert with metabasaltic intercalations (Upper Cretaceous?) reflect platform collapse. Overlying mélange contains blocks of ocean-derived intrusive and extrusive igneous rocks (e.g. ocean island-type basalt), metacarbonates and radiolarian chert, set in a low-grade metamorphosed shaly matrix. The Tavşanlı Zone was buried in a north-dipping subduction zone to 74–79 km at c. 88 Ma, exhumed and tectonically juxtaposed with accretionary mélange prior to the Late Palaeocene–Early Eocene. Geochemical studies of the meta-igneous rocks indicate the presence of ocean island basalt (OIB) and mid-ocean ridge basalt (MORB) sources modified by crustal contamination, evidenced by Th enrichment and fractional crystallization. A subduction chemical influence in the lower part of the succession (e.g. Nb depletion) was probably derived from subcontinental mantle lithosphere, modified during some previous subduction event (Panafrican?).supplementary-material: Full geochemical data are available at www.geolsoc.org.uk/SUP18570

Description: Continental margin-type, ophiolitic and mélange units are exposed throughout central eastern Turkey (e.g. Gürün, Hekimhan and Pınarbaşı areas). These restore as a north-verging Triassic-rifted continental margin that underwent Jurassic–Early Cretaceous passive margin subsidence. Chemically ‘enriched’ basaltic lavas of seamount type are interbedded with and overlain by Middle Jurassic–Early Cretaceous ribbon cherts. Ophiolitic rocks (e.g. Pınarbaşı, Dağlıca, Kuluncak, Hekimhan, Divriği) formed by spreading above a Late Cretaceous northwards-dipping intra-oceanic subduction zone. Emplacement of continental margin units, mélanges and ophiolites onto the East Tauride platform was driven by trench-margin collision during latest Cretaceous. The northern part of the East Tauride neritic carbonate platform detached and overthrust the continent to the south (Malatya Metamorphics) which was deeply underthrust, metamorphosed at least to greenschist facies and exhumed by latest Cretaceous. Collision-related Mid-Eocene southwards thrusting strongly affected the western part of the region (e.g. Pınarbaşı), whereas areas further east (e.g. Darende, Hekimhan, Divriği, Sivas) mainly experienced folding. Taking account of the regional tectonic setting, we infer that the Gürün platform, with its distinctive unbroken up to Lutetian-aged succession, represents a small exotic terrane that was translated from a relatively southerly (‘internal’) part of the Tauride platform (Geyik Dağ), related to strike-slip displacement (syn/post-Eocene to pre-Pliocene).Supplementary material: Two supplementary tables giving the GPS coordinates of the samples of basic intrusive and extrusive igneous rocks that were analyzed during this work are available at www.geolsoc.org.uk/SUP18569

Description: The Plio-Quaternary Eşen Çay Basin is situated at the junction of Hellenic and Cyprus arcs in southwestern Turkey. The basin is important for understanding the tectonic evolution of the region in relation to the Hellenic and Cyprus arcs. Fault data from unconsolidated Pliocene and Quaternary deposits, as well as from pre-Pliocene lithologies, are analysed in order to reconstruct the evolution of the stress field evolution from Pliocene onwards. Inversion of measured fault slip vector data identifies two main stress states: extensional and strike-slip. Both states are characterized by a NE–SW-trending minimum horizontal stress axis (σHmin=σ3). The mean R value is 0.67, indicating a triaxial state of stress. The inversion also indicates the existence of extensional and strike-slip faulting characterized by a NW–SE-trending σ3 axis. This indicates a change in the direction of the minimum horizontal stress axis (σ3) from a NW–SE-trending σ3 that dominated prior to Quaternary to a NE–SW-trending σ3 that dominated during Quaternary up to actual time.

Description: The Darende Basin is an excellent example of an important, but little known, type of sedimentary basin that can form on the top of emplaced ophiolites prior to and during continental collision. The basin formation was preceded by southward emplacement of accretionary mélange and ophiolites onto the Tauride carbonate platform during latest Cretaceous. Sedimentation began during the Maastrichtian with non-marine clastic sediments accumulating in palaeovalleys. This was followed by a Maastrichtian marine transgression, triggered by extension along the basin margins. Rudist-rich patch reefs and a carbonate shelf developed in different areas. A second transgression during the Mid-Eocene was preceded by emergence, a hiatus (Paleocene), localized faulting and low-angle (〈5–10°) tilting. Middle Eocene hemipelagic marls, shallow-marine Nummulites-rich carbonates, calciturbidites and sparse alkaline volcanism culminated in Late Eocene shallowing, emergence and then deformation. The first phase of basin development (Maastrichtian) is seen as extensional, related to slab-pull that resulted from northward subduction of remnant oceanic lithosphere beneath Eurasia in the Pontides to the north. The second phase of basin development (Mid–Late Eocene) is explained by crustal downflexure to form an under-filled foreland basin during the final collision of the Tauride continent with Eurasia. Basin uplift was delayed until after a Mid-Miocene marine incursion.Supplementary material: Full results of the palaeontological determination of collected samples from the Eocene aged sedimentary rocks of the Darende Basin are available at www.geolsoc.org.uk/SUP18544

Description: We present palaeomagnetic results from the Oligocene through Miocene part of the Integrated Ocean Drilling Program Site U1333 (1030.996′N, 138°25.159′W), which is located in 4853 m-deep water over seafloor with an estimated crustal age of 46 Ma. Detailed magnetostratigraphic investigations are essential to provide a sound age model for the study of the palaeoclimatic and palaeo-oceanographic history of the Cenozoic of the Equatorial Pacific and to improve the database of Pacific magnetostratigraphy. Rock magnetic measurements were carried out at 1 cm resolution on 81 U-channel samples from the spliced section with the goal of extracting a high-resolution record of the magnetostratigraphy. Stepwise demagnetization of the natural remanent magnetization yielded a well-defined magnetostratigraphy over a time interval of approximately 10 Ma between the base of Chron C6n (19.722 Ma) and the middle of Chron C11r (〉29.9 Ma) and identification of the Oligocene–Miocene transition at the base of Subchron C6Cn.2n. The palaeomagnetic data are characterized by shallow inclinations, and by 180° alternations in declinations downhole, reflecting magnetic polarity zones. The relatively high temporal resolution allowed for the identification of three possible excursions previously not identified on the geomagnetic polarity time scale, which were recorded in Subchrons C8n.1r and C11n.2n and in Chron C11r.

Description: Palaeomagnetic and palaeoenvironmental data from Indonesia and particularly from the Island of Sulawesi are scarce and exact dating has turned out to be a challenge in many archives from this region. Here we outline difficulties in radiocarbon dating of the palaeoenvironmental record from Lake Kalimpaa, Sulawesi, Indonesia. These difficulties demand the integration of additional parameters to obtain a reliable chronology for this record. Thus, we compare the palaeomagnetic secular variation data from this record with the CALS3k.4 spherical harmonic geomagnetic model of the 0–3 ka field (Korte & Constable 2011). The resulting age–depth model for the Lake Kalimpaa sequence provides a profound basis for further multi-proxy investigations on this record. For the first time, high-resolution palaeomagnetic secular variation data continuously spanning the past 1300 years are presented for this region, which complement existing records with lower temporal resolution or records missing the top-most sections.

Description: Lithostratigraphic, magnetostratigraphic and rock-magnetic cyclostratigraphic data were combined to create a high-resolution age model for 342 m of Late Pliocene–Middle Pleistocene marine deposits exposed in the Stirone River, northern Italy. Magnetostratigraphic analysis of 74 oriented samples at 21 stratigraphic horizons recognized five polarity zones between c. 3.0 and 1.0 Ma. Unoriented samples were collected every metre between 0 and 311 m and low-field magnetic susceptibility (χ) was measured for cyclostratigraphic analysis. The χ data series was tied to absolute time using the magnetostratigraphy and subjected to multi-taper method spectral analysis. The resultant power spectra revealed significant frequency peaks that are aligned with eccentricity, obliquity and precession Milankovitch orbital cycles. The χ data, correlated to the 41 ka obliquity and the 23 ka/19 ka precession cycles and anchored to a well-established biostratigraphic horizon, were used to create a high-resolution age model for the Stirone section between 2.99 and 1.81 Ma, where stratigraphic positions of magnetic reversals were previously poorly defined. This cyclostratigraphic age model reveals that the length of an important depositional hiatus at the base of the C2An.1n subchron is 200 ka shorter than previously determined. We link the precession-aligned variability in χ to global mid-latitude, insolation-induced variability in runoff and ocean circulation.

Description: Rock magnetic cyclostratigraphy was measured in the Barremian–Aptian Cupido (‘Cupidito’) Formation, northeastern Mexico. The goal was to develop an objective evaluation of palaeo-environmental variability recorded in the formation that is independent of facies analysis and interpretation. Anhysteretic remanent magnetization (ARM) was used to estimate magnetic mineral concentration variations for the upper 143 m of the formation, which is characterized by metre-scale carbonate cycles representative of inner- and middle-shelf marine environments. Isothermal remanent magnetization acquisition experiments and scanning electron microscope (SEM) examination indicate that micron-sized detrital magnetite from eolian dust carries the ARM signal. At the sampled sections from Garcia and Chico canyons, 25 km apart, ARM records a synchronous 30–35 m oscillation with maxima coinciding with fourth-order sequence boundaries, superimposed with prominent high-frequency variability. Calibrating the 30–35 m oscillation to a 405 kyr period (long eccentricity cycle) focuses the high frequencies into short eccentricity, obliquity and precession index bands; the precession-band signal modulates with an eccentricity signature. The ARM signal is correlated between sections, but decoupled from the interpreted fifth-order depositional cycles. ARM amplitudes diminish up-section with facies suggesting deepening conditions that diluted magnetite concentration. This probably signals a warming, increasingly humid climate, changing global circulation and/or greater dispersal of magnetite grains.

Description: Ichnological evidence suggests that dinosauromorphs originated by the Early Triassic, and skeletal remains of non-dinosaur representatives of the clade occur from the Anisian to the end of the Triassic. These taxa are small- to medium-sized, vary in feeding and locomotor features, and occurred over most of western Pangaea. They include the small lagerpetids from the Mid–Late Triassic of Argentina and the United States, and the larger, quadrupedal Silesauridae, with records in the Middle Triassic of Africa and Argentina, and in the Late Triassic of Europe, the Americas and northern Africa. The former group represents the earliest diverging dinosauromorphs, whereas silesaurids are more closely related to Dinosauria. Other dinosauromorphs include the archetypal early dinosauriform Marasuchus lilloensis (Middle Triassic of Argentina) and poorly known/controversial taxa such as Lewisuchus admixtus and Saltopus elginensis. The earliest diverging dinosauromorphs may have preyed on small animals (including insects), but cranio-dental remains are rare; by contrast, most silesaurids probably included plant material in their diet, as indicated by their modified jaw apparatus and teeth. Our knowledge of the anatomy and thus relationships of non-dinosaurian Dinosauromorpha is still deficient, and we suspect that future discoveries will continue to reveal novel patterns and hypotheses of palaeobiology and biogeography.

Description: Proterochampsia is a monophyletic group of crocodile-like archosauriforms currently endemic to the late Middle and early Late Triassic of South America considered as one of the potential successive sister-taxa of the crown group Archosauria. The proterochampsians come from the Ischigualasto-Villa Unión Basin in the west of Argentina and the Parana Basin in the south of Brazil. The traditional composition of the group includes the genera Cerritosaurus Price 1946, Proterochampsa Reig 1959 (with two species: P. barrionuevoi in Argentina and P. nodosa Barberena 1982 in Brazil), Chanaresuchus Romer (with two species from Argentina: C. bonapartei Romer and C. ischigualastensis Trotteyn et al. 2012), Gualosuchus reigi Romer 1971 and Tropidosuchus romeri Arcucci 1990. After a precladistic history of confusion about their relationships with crocodilians, in the last 20 years new discoveries of taxa, and more systematic and phylogenetic studies, have clarified their position as non-archosaurian archosauriforms and their relationships with other Triassic archosaurs.

Description: The virtual geomagnetic pole (VGP) trajectories during some geomagnetic polarity reversals of different ages are marked by anisotropic behaviour. This recurrent phenomenon may be reflected in the paleomagnetic data, even if the transitional field was not completely recorded. As the long-scale geomagnetic variations have a confined oscillatory character, the VGP paths from stratigraphically controlled sequences may be described on the basis of sine and cosine functions, even if time is not the independent variable. Here we considered longitude (or space) as the independent variable which had to be ‘unrolled’ to overcome the 360° repetitions as the VGPs moved around the geographic pole.Sixteen VGP series from the Early Cretaceous Serra Geral lava flows of southern Brazil were analysed using a modified version of the periodogram for uneven data series, and a combination of information approach. The combination of all the spectra, as in a stacking procedure, reduces noise and results in a smooth curve highlighting features of interest. We found a set of highest correlation wavelengths of approximately 167, 190, 209, 257, 277 and 368°. Phase analyses using two different methods revealed strikingly good coherence for some of these wavelengths, indicating that they are not only artefacts of the spectral analysis. Similar analysis of magnetostratigraphic data from the Icelandic Magmatic Province indicated that the two datasets may have wavelengths of approximately 165 and 270° in common. These results suggest quasi-periodic behaviour, possibly with sub-harmonic instabilities owing to the modulating effect of inner Earth's anisotropies influencing the pole trajectory.

Description: Applying time-series analyses using Fourier transform and multi-taper methods to low-field, mass-specific magnetic susceptibility (χ) measurements on marine samples from well-studied shale and limestone outcrops of the Upper Ordovician (Edenian Stage; Upper Katian) Kope Formation, northern Kentucky, corroborates direct visual identification in outcrops of Milankovitch eccentricity (c. 405 and 100 ka), obliquity and precessional climate cycles. Because individual outcrops were too short and deposition too chaotic to yield significant time-series results, it was necessary to build a c. 50 m thick composite sequence from three well-correlated outcrops to quantify the cyclicity. Time-series analysis was then performed using χ measured for 1004 closely spaced samples covering the section. Milankovitch bands are recorded in the time-series data from the composite. We tested this result by comparison of these bands to cyclic packages in outcrop, which correspond to thicknesses represented in the time-series datasets. This is particularly well defined for the eccentricity and obliquity cycles, with precessional bands being evident but as less well-defined packages of beds.

Description: In this study we examine glaciogenic rhythmites from the Late Palaeozoic Itararé Group, Paraná Basin, Brazil. We conduct spectral analysis on lithological cycle (‘couplet’) thickness series, and declination of maximum axis of anisotropy of magnetic susceptibility ellipsoidal tensor (K1) data. We tested the efficiency of K1 as a palaeoclimatic proxy. To constrain the timescale of harmonic features in the data, we analysed the couplet thickness spectra, converting the spectra to the time domain using an astronomical calibration based on Milankovitch frequency ratios. Comparison of the two rhythmites provides insights into their sedimentation rate evolution and cyclicity. Millennial-scale mechanisms of climatic origin influenced the deposition of both rhythmites, generating the lithological couplets, and are consistent with millennial-scale variations recognized as triggers for large-scale climatic changes during the Late Pleistocene. The common harmonic features in the couplet thickness and K1 spectra support the view that the azimuth of the K1 axis in sedimentary fabric is a useful palaeoclimatic proxy, reflecting sedimentation processes that were directly influenced by flow-induced, sediment transport, which is linked to external climate factors.

Description: Vertical-axis rotations of blocks in/around the Tibetan Plateau can be attributed to the India–Asia collision. Study of the vertical-axis rotations of these blocks will increase our understanding of the mechanisms and kinematics of continent–continent collisions. We report here a new palaeomagnetic study of rotations using data from four localities (five magnetostratigraphy sections) in the Jiuquan Basin. Our study indicates that the mean declinations of each section are different from each other, similar to what has been observed in the other localities in the NE Tibetan Plateau. However, using the mean directions of every 100 m of section, we observe that the four localities have similar sequential patterns of rotations during the last 13 Ma: significant continuous counterclockwise before c. 8.0 Ma, insignificant rotations between 8.0–4.0 Ma, and slight clockwise rotation after 4.0 Ma. This indicates that, rather than being a record of spatially varying declinations, it is a temporal variation in the occurrence of regional rotations. Combined with other geological evidence, the rotation patterns may suggest two major tectonic activity phases of the northeastern Tibetan Plateau during the last 13 Ma: an eastward extrusion and strike-slip dominant phase before 8.0 Ma, a significant shortening and a rapid uplift dominant phase after 8.0 Ma.Supplementary material: Magnetostratigraphic results of the Hongshuiba and Wenshushan sections are available at: http://www.geolsoc.org.uk/SUP18540.

Description: Here we establish a magnetostratigraphy susceptibility zonation for the three Middle Permian Global boundary Stratotype Sections and Points (GSSPs) that have recently been defined, located in Guadalupe Mountains National Park, West Texas, USA. These GSSPs, all within the Middle Permian Guadalupian Series, define (1) the base of the Roadian Stage (base of the Guadalupian Series), (2) the base of the Wordian Stage and (3) the base of the Capitanian Stage. Data from two additional stratigraphic successions in the region, equivalent in age to the Kungurian–Roadian and Wordian–Capitanian boundary intervals, are also reported. Based on low-field, mass specific magnetic susceptibility (χ) measurements of 706 closely spaced samples from these stratigraphic sections and time-series analysis of one of these sections, we (1) define the magnetostratigraphy susceptibility zonation for the three Guadalupian Series Global boundary Stratotype Sections and Points; (2) demonstrate that χ datasets provide a proxy for climate cyclicity; (3) give quantitative estimates of the time it took for some of these sediments to accumulate; (4) give the rates at which sediments were accumulated; (5) allow more precise correlation to equivalent sections in the region; (6) identify anomalous stratigraphic horizons; and (7) give estimates for timing and duration of geological events within sections.

Description: The earliest history of Archosauriformes is mainly represented by members of Proterosuchidae and Erythrosuchidae, which are known worldwide from latest Permian to Middle Triassic beds. These two groups were historically combined within ‘Proterosuchia’, with approximately 30 nominal species. Two morphotypes have been recognized among proterosuchians: proterosuchids with a generally more sprawling gait and elongated and low skulls with an overhanging premaxilla, and the more heavily built erythrosuchids, with a probably less sprawling gait and large, presumably hypercarnivorous, skulls. The systematics of ‘Proterosuchia’ was relatively chaotic throughout most of the twentieth century, but currently there exists consensus regarding the non-monophyly of proterosuchians and their phylogenetic position outside all other archosauriforms. In contrast, the delimitation and taxonomic content of Proterosuchidae and Erythrosuchidae remain unstable. Few studies of proterosuchian palaeobiology have been carried out. Current lines of evidence favour a predominantly terrestrial lifestyle for proterosuchians. Limb bone histology indicates rapid continuous growth rates in Proterosuchus and Erythrosuchus before reaching sexual maturity. A better knowledge of proterosuchian anatomy, systematics, evolution and ecology is important for advancing understanding of the origin and early radiation of Archosauriformes and the patterns of biotic recovery following the Permo-Triassic mass extinction event. There remains much research to be carried out in proterosuchian palaeobiology.

Description: We have studied the rock magnetic and palaeomagnetic properties of a 41 m long core (Hole M0058A) recovering calcareous sediments located seaward of Noggin Reef, offshore Queensland, Australia to decipher the magnetostratigrapy of the site. We deployed 1 cm3 samples at every 10 cm down-core and subsampled the core by means of U-channels in order to obtain a continuous record. Stepwise alternating field demagnetization from natural remanent magnetization to 80 mT showed that the characteristic remanent magnetization was isolated at low demagnetization fields between 0 and 15 mT. We conducted magnetic granulometry analyses and Curie point determinations. The low-field v. temperature analyses indicate the presence of Ti-poor magnetite with Curie points from 560 to 563 °C. Hysteresis loop experiments were performed. The results show Mrs/Ms and Hcr/Hc ratios corresponding to single domain to multi-domain and super-paramagnetic to single domain ranges. Both discrete and continuous inclination results indicate a remarkable correlation of three excursional inclinations occurring during intervals of low intensity of magnetization closely corresponding to the Laschamp (c. 41 ka), Skálamælifell (c. 94 ka) and Blake (c. 115–120 ka) ‘aborted reversals,’ and indicate that the base of the core is much older than the Blake excursion.

Description: ‘Rauisuchia’ comprises Triassic pseudosuchians that ranged greatly in body size, locomotor styles and feeding ecologies. Our concept of what constitutes a rauisuchian is changing as a result of discoveries over the last 15 years. New evidence has shown that rauisuchians are probably not a natural (monophyletic) group, but instead are a number of smaller clades (e.g. Rauisuchidae, Ctenosauriscidae, Shuvosauridae) that may not be each other's closest relatives within Pseudosuchia. Here, we acknowledge that there are still large gaps in the basic understanding in the alpha-level taxonomy and relationships of these groups, but good progress is being made. As a result of renewed interest in rauisuchians, an expanding number of recent studies have focused on the growth, locomotor habits, and biomechanics of these animals, and we review these studies here. We are clearly in the midst of a renaissance in our understanding of rauisuchian evolution and the continuation of detailed descriptions, the development of explicit phylogenetic hypotheses, and explicit palaeobiological studies are essential in advancing our knowledge of these extinct animals.

Description: Proterochampsians are basal archosauriforms whose record is restricted to the Middle and Upper Triassic in Argentina and Brazil. They are quadruped forms that present characteristics consistent with a semi-aquatic lifestyle, such as an anteroposteriorly elongated skull that is flattened dorsoventrally with dorsally located orbits. In 2003, specimen UFRGS-PV-0877-T was discovered at the Schoenstadt site, in the city of Santa Cruz do Sul (Santacruzodon Assemblage Zone, Santa Maria Formation). This specimen, consisting of disarticulated cranial elements (such as nasals, frontals, parietals, postorbitals, a left squamosal, a left pterygoid and a fragment of a right mandibular ramus that bears teeth) and postcranial elements (such as femora, the left tibia, one vertebral centrum and two rib fragments), is assigned to the ‘proterochampsian’ Chanaresuchus bonapartei Romer (1971). This assignment is based on the shared V-shaped frontal-parietal suture of the new specimen and Chanaresuchus bonapartei, which differs from the transversely aligned and zigzagged pattern of C. ischigualastensis.

Description: Aetosauria is a clade of obligately quadrupedal, heavily armoured pseudosuchians known from Upper Triassic (late Carnian–Rhaetian) strata on every modern continent except Australia and Antarctica. As many as 22 genera and 26 species ranging from 1 to 6 m in length, and with a body mass ranging from less than 10 to more than 500 kg, are known. Aetosauroides scagliai was recently recovered as the most basal aetosaur, placed outside of Stagonolepididae (the last common ancestor of Desmatosuchus and Aetosaurus). Interrelationships among the basal aetosaurs are not well understood but two clades with relatively apomorphic armour – the spinose Desmatosuchinae and the generally wide-bodied Typothoracisinae – are consistently recognized. Paramedian and lateral osteoderms are often distinctive at the generic level but variation within the carapace is not well understood in many taxa, warranting caution in assigning isolated osteoderms to specific taxa. The aetosaur skull and dentition varies across taxa, and there is increasing evidence that at least some aetosaurs relied on invertebrates and/or small vertebrates as a food source. Histological evidence indicates that, after an initial period of rapid growth, lines of arrested growth (LAGs) are common and later growth was relatively slow. The common and widespread Late Triassic ichnogenus Brachychirotherium probably represents the track of an aetosaur.

Description: Silesauridae is an exclusively Triassic group of dinosauromorphs, knowledge on the diversity of which has increased dramatically in the last few years. Silesaurid relationships are still contentious, as a result in part of different homology statements, particularly regarding the typical edentulous mandible tip of these animals. One of the most complete silesaurids yet discovered is Sacisaurus agudoensis from the Caturrita Formation (Late Triassic: Norian) of Rio Grande do Sul, Brazil, represented by numerous isolated bones recovered from a single site. The anatomy of S. agudoensis is fully described for the first time here, and comparisons are provided to other basal dinosauromorphs. S. agudoensis is a small-bodied animal (less than 1 m in length) that possesses a dentition consisting of leaf-shaped crowns with large denticles in the carinae, a plesiomorphic propubic pelvis with an almost fully closed acetabulum, elongate distal hindlimbs suggesting well-developed cursorial ability, and a laterally projected outer malleolus in the tibia. All previous numerical phylogenies supported a non-dinosaur dinosauromorph affinity for Silesauridae, but the reanalysis of one of those studies suggests that a position within Dinosauria is not unlikely, with silesaurids forming the basal branch of the ornithischian lineage.

Description: Postosuchus kirkpatricki is a Late Triassic (Norian) ‘rauisuchid’ archosaur from North America. The initial description of the Postosuchus type material included elements from two poposaurids. This confusion has prevented adequate description of the material. Recent examination of the type material and other specimens of Postosuchus, and of related taxa, has helped clarify the osteology of Postosuchus. The type specimens represent c. 75% of the skeleton. Together with other referred material, Postosuchus remains one of the most completely known rauisuchids. The paratype skeleton, which is relatively complete, would have been c. 3.5–4 m in length, and the holotype would have been closer to 5–6 m.Analysis of the postcranial skeleton of Postosuchus suggests that it may have been an obligate biped (based in part on limb proportions, which are similar to some theropod dinosaurs, the size of the manus (30% of the size of the pes) and the highly reduced nature of the digits and vertebral measurements). Possible postcranial autapomorphies of Postosuchus include a large, rugose triangular supra-acetabular buttress confluent with the dorsal margin of the iliac blade, and a symmetrical pes with digits two and three being roughly equal in length.

Description: The main objective of this book is to provide a global overview of divergent margins based on geological and geophysical interpretation of sedimentary basins along the South, Central and North Atlantic conjugate margins, from plate tectonics and crustal scales to a more detailed description of stratigraphical and structural elements that are responsible for petroleum plays. These themes are complemented by geodynamic concepts based on physical and numerical models, and by comparisons with present-day embryonic margins, which are succinctly discussed in some papers.Supplementary material: Three plate animations of the Atlantic Ocean are available at www.geolsoc.org.uk/SUP18620.

Description: Continental break-up mechanisms vary systematically between slow- and fast-extension systems. Slow-extension break-up has been established from studies of the Central Atlantic, European and Adria margins. This study focuses on the intermediate and fast cases from Gabon and East India, and draws from the interpretation of reflection seismic, gravimetric and magnetic data.Interpretation indicates continental break-up via continental mantle unroofing in all systems, with modifications produced by magmatism in faster-extension systems. Break-up of the intermediate-extension Gabon system involves partial upper continental crustal decoupling from continental mantle; whereas, in the fast East Coast India system, decoupled and lower-crustal regimes underwent upwarping in ‘soggy’ zones in the footwalls of major normal faults. Usually, upper-crustal break-up is affected by pre-existing anisotropies, which form systems of constraining ‘rails’ for extending continental crust. This modifies the local stress regimes. They regain a regional character as the function of constraining rails vanishes during progressive unroofing of the upper mantle. Different regions attain different amounts of upper-crustal stretching prior to the break-up. The break-up location is then controlled by the upper-crustal energy balance principle of ‘wound linkage’, by which the minimum physical work is performed for linking upper-crustal ‘wounds’, leading to successful upper-crustal break-up.Supplementary material: Supplementary information and figures on the modelling of the mechanisms and architecture is available at http://www.geolsoc.org.uk/SUP18525.

Description: Metamorphic and igneous rocks exposed in NW-vergent thrust sheets and their autocthonous basement in the NE Pontides were dated by the U–Pb method using zircons, supported by geochemical data for granitic rocks. Two meta-sedimentary units (Narlık schist and Karadağ paragneiss) yielded detrital zircon populations of 0.50–0.65 and 0.9–1.1 Ga, suggesting an affinity with NE Africa (part of Gondwana). The youngest concordant zircon age is Ediacaran for the schist but Devonian for the paragneiss, bracketing the paragneiss depositional age as Mid-Devonian to Early Carboniferous. Metamorphic rims of zircon cores in the paragneiss gave Carboniferous ages (345–310 Ma). The zircon rim data indicate two Variscan metamorphic events (334 and 314 Ma) separated by a hiatus (320–325 Ma). Granite emplacement took place during early Carboniferous, Early Jurassic and Late Jurassic phases. The crystallization age of the early Carboniferous granites (c. 325 Ma) corresponds to a hiatus in the zircon age data that could reflect subduction slab break-off. The Variscan granitic rocks intruded a Gondwana-derived continental terrane that was loosely accreted to Eurasia during early–late Carboniferous time but remained isolated from Eurasian-derived terrigenous sediment. In contrast, the Jurassic granitic magmatism relates to later back-arc extension along the southern margin of Eurasia.Supplementary material: Full isotope data (8 tables) are available at www.geolsoc.org.uk/SUP18558

Description: The Upper Cretaceous–Mid-Eocene Kırıkkale, Tuz Gölü, Haymana and Çankırı basins are bounded by the Pontide (Eurasian) continental margin to the north, the Niğde–Kırşehir microcontinent to the east and the Tauride–Anatolide continental unit to the south. The basins developed during northward subduction/collision of the İzmir–Ankara–Erzincan Ocean (‘northern Neotethys’) in the north and the inferred Inner Tauride Ocean in the south. Subduction of the İzmir–Ankara–Erzincan Ocean resulted in latest Cretaceous collision of the Niğde–Kırşehir microcontinent with the Pontide active margin and ophiolite emplacement. Some mid-ocean ridge-type oceanic crust remained to the SW and formed the basement of the Kırıkkale and Tuz Gölü basins. These basins are partially floored by an accretionary wedge to the west and by the Niğde–Kırşehir microcontinent to the east. Locally volcaniclastic, the sediment infill switched to terrigenous after latest Cretaceous. The Haymana Basin, further NW, developed as a forearc basin on the Mesozoic accretionary wedge and Pontide continental fragments. The Çankırı Basin also developed on an accretionary wedge, bounded by the Eurasian active margin to the north. An extensional setting prevailed during the latest Cretaceous related to subduction of remnant oceanic crust, followed by a switch to regional compression during Late Paleocene–Mid Eocene progressive and diachronous collision.

Description: The Kannaviou Formation (up to 750 m thick) accumulated in a deep-sea setting in west Cyprus during Campanian–Early(?) Maastrichtian time. The formation depositionally overlies Upper Cretaceous ophiolitic lavas, including those associated with serpentinite-hosted arcuate lineaments. The Kannaviou Formation locally overlies ophiolitic serpentinite, indicating that mantle rocks were exposed on the seafloor prior to sediment deposition. Geochemical analyses of basalts that depositionally underlie the Kannaviou Formation, within the arcuate lineaments, indicate close similarities with the boninitic lavas of the South Troodos Transform Fault Zone in south Cyprus. Abundant volcanogenic and minor terrigenous and pelagic sedimentary rock material is present within the Kannaviou Formation, while kaolinite is common within interbedded red clays. Suitable terrigenous source lithologies are present in the deformed continental margin/deep-sea sedimentary rocks of the Mamonia Complex in west Cyprus. Whole-rock chemical analysis of sandstones of predominantly volcaniclastic origin indicates an intermediate arc-like composition. Electron microprobe analysis shows that glass is silicic, with a tholeiitic fractionation trend. Similar arc-like volcanic rocks of Late Cretaceous age are exposed in the western Kyrenia (Girne) Range, north Cyprus. The provenance of the Kannaviou Formation provides evidence of Late Cretaceous northwards subduction of the South Neotethys beneath a continental margin to the north.Supplementary material: The sample locations, complete chemical analyses, electron probe data and x-ray diffraction results are available at www.geolsoc.org.uk/SUP18579

Description: A detailed account is given of the fault geometry and segment structure of the East Anatolian Fault Zone as a whole based on mapping of active faults, supported by available seismological and palaeoseismological data. We divide the East Anatolian Fault into two main strands: southern and northern. The main southern strand is c. 580 km long between Karlıova and Antakya, and connects with the Dead Sea Fault Zone and the Cyprus Arc via the Amik triple junction. The northern strand, termed the Sürgü–Misis Fault system, is c. 350 km long and connects with the Kyrenia–Misis Fault Zone beneath the Gulf of İskenderun. We infer that slip partitioning between the main and northern strands of the East Anatolian Fault accommodates 2/3 and 1/3 of the slip rate of the lateral motion between the Arabian and Anatolian plates, respectively in the Çelikhan–Adana–Antakya region. Taking account of the time elapsed from the latest events on the East Anatolian Fault, we suggest that the Pazarcık and Amanos segments have the potential to produce destructive earthquakes in the near future.Supplementary material: The data and interpretations given here are supported by five additional annotated field photographs and two tables of factual data, these are available at www.geolsoc.org.uk/SUP18568

Description: During Late Cretaceous–Mid-Eocene the Girne (Kyrenia) Range formed part of the northerly active continental margin of the southern Neotethys. Following Late Eocene–Late Miocene mainly deep-marine clastic deposition, the range was thrust southwards in a convergent (transpressional) stress regime during Late Miocene (Messinian)–earliest Pliocene time. Sinistral transpression is most evident near the front of the range in the east and in several segments, implying strain compartmentalization. The range was relatively quiescent during Early–Mid Pliocene, followed by strong c. east–west-trending uplift during Late Pliocene–Pleistocene. Further south, the east–west Dar Dere (Ovgos) lineament was active as a north-down extensional (or transtensional) fault zone during Oligocene–Mid-Miocene. Sinistral strike-slip/transpression followed during Late Miocene, followed by strike-slip at least during Late Pliocene–Pleistocene. The latest Miocene–earliest Pliocene thrusting/oblique convergence reflects closure of the southern Neotethys and tightening of the suture between the Arabian (North African) and Turkish (Eurasian) continents. Collision-related uplift of the Girne (Kyrenia) Range and the Troodos Massif further south took place from Late Pliocene time onwards. The Dar Dere (Ovgos) lineament is interpreted as a terrane boundary that was reactivated related to westward tectonic escape of Anatolia during Neogene–Recent time. The structure as a whole reflects regional diachronous continental collision.Supplementary material: Detailed geological maps of key areas to the south and north of the Girne (Kyrenia) Range based on regional mapping and field observations are available at www.geolsoc.org.uk/SUP18534.

Description: Most existing tectonic models suggest Pliocene–Quaternary deformation and uplift of the NE Tibetan Plateau in response to the collision of India with Asia. Within the NE Tibetan Plateau, growth of the terranes was suggested to progress northeastward with the Yumu Shan (mountain) at the northeasternmost corner of the Qilian Shan (mountains) being uplifted only since about 1 Ma ago. Here we present a detailed palaeomagnetic dating and tectonosedimentological measurement of Cenozoic sediments in the eastern Jiuquan Basin related to the deformation and uplift of the North Qilian Shan and Yumu Shan. The results show that the eastern Jiuquan Basin is a Cenozoic foreland basin and received sediments at about 27.8 Ma at the latest. Eight subsequent tectonic events at about 27.8, 24.6, 13.7–13, 9.8–9.6, 5.1–3.6, 2.8–2.6, 0.8 and 0.1 Ma demonstrate the development of the foreland basin in response to Oligocene–Quaternary uplift of the North Qilian Shan and subsequent propagation of thrust–fold system owing to collision of India with Asia. The Yumu Shan is the late phase of deformation front in the thrust–fold system and commenced rapid uplift at about 9.8–9.6 Ma at the latest. A rigid block-floating model is proposed to interpret the mechanism of this deformation and uplift history.

Description: Archosaurs, an important reptile group that includes today's crocodiles and birds, arose during the Triassic in the aftermath of the greatest mass extinction of all time. In the last 20 years, our understanding of the early evolution of the group has improved substantially with the discovery of new fossils and species of early archosaurs and their closest relatives, a better understanding of the relationships of these animals, and new insights into their palaeobiology. In order to synthesize these new data, researchers of early archosaurs from around the world met at the first symposium of early archosaur evolution at the IV Congreso Latinoamericano de Paleontología de Vertebrados (September 2011) in San Juan, Argentina. This symposium facilitated collaboration and strove to paint a better understanding of these extraordinary animals. The resultant body of work is a state-of-the-art examination of early archosaur groups and their close relatives including historical, anatomical, biogeographical, evolutionary and palaeobiological data. This contribution furthers our knowledge of the anatomy, relationships, and palaeobiology of species-level taxa as well as more global patterns of archosaur evolution during the Triassic.

Description: Doswelliidae is a clade of armoured non-archosaurian archosauriform reptiles more closely related to Archosauria than are Proterosuchidae, Erythrosuchidae and possibly Euparkeria capensis. It is currently known from the late Middle Triassic (Ladinian) of Germany, the late Middle to early Late Triassic (Ladinian–Carnian) of Argentina and Brazil, and the Late Triassic (Carnian–Norian) of the USA. To date, two unambiguous synapomorphies diagnose Doswelliidae: (i) osteoderm ornamentation coarse, incised, and composed of central regular pits of subequal size and shape, and (ii) osteoderms with anterior articular lamina. Five taxa are currently recognized: Archeopelta arborensis, Doswellia kaltenbachi, Doswellia sixmilensis, Tarjadia ruthae and a new taxon from Germany. Based on skeletal features and occurrence, doswelliid archosauriforms may have had a semi-aquatic mode of life.

Description: Phytosauria is a nearly cosmopolitan clade of large, quadrupedal, carnivorous archosauriforms. They are known unambiguously from Late Triassic deposits, although the clade’s ghost lineage extends at least to the late Early Triassic. Their nares are uniquely located close to the orbits rather than anteriorly in the rostrum as in modern crocodylians, and the rostrum is formed by elongated premaxillae bearing many teeth. Phytosaurs have roughly triangular, ornamented paramedian osteoderms, rounder appendicular osteoderms, and a unique ‘gular shield’ assembled from multiple, irregular osteoderms under the throat. Phytosaurs are reconstructed as semi-aquatic because of their general similarity to modern crocodylians and common preservation in fluvial and shallow-marine deposits. Currently, over thirty species are recognized. New specimens continue to be collected, some representing new taxa. The taxonomic status of other named taxa is uncertain and requires re-investigation. Since their discovery, phytosaurs have been used as biostratigraphic and biochronological index taxa for correlating Late Triassic sediments worldwide. Recent systematic and taxonomic revisions cast doubt on some of those correlations. Our understanding of the evolution of Phytosauria is far from complete. With reevaluation of well-known specimens, rigorous and comparative morphological descriptions, and robust phylogenetic hypotheses of ingroup relationships, studies of phytosaurs can address larger palaeobiological questions.

Description: The osteology of an almost complete braincase of the rauisuchian archosaur Prestosuchus chiniquensis from the Middle Triassic of Brazil is described for first time, based on two specimens (UFRGS-PV-0629-T and UFRGS-PV-0156-T). A comparative description with other taxa of rauisuchians is presented that forms the basis of a phylogenetic analysis. To perform the phylogenetic analysis, we describe and discuss each character codification for a modified version of the recent matrices of Gower (2002), Gower & Nesbitt (2006) and Brusatte et al. (2010). The analysis resulted in two most parsimonious trees that differ from the topologies recovered by Gower (2002) in a few aspects within Rauisuchia, and Prestosuchus chiniquensis was unequivocally depicted as deeply nested within Pseudosuchia, as the sister taxon of Batrachotomus kuperferzellensis in both topologies, supported by a single synapomorphy: the reduced to small fissure of the post-temporal fenestra between parietal, supraoccipital and exoccipital-opisthotic.

Description: The partial postcrania of Poposaurus gracilis, a bipedal poposauroid convergent with theropod dinosaurs, has been known for nearly a century, but the skull of P. gracilis has proven elusive. P. gracilis is part of a clade of morphologically divergent pseudosuchians (poposauroids) whose members are sometimes bipedal, lack dentition (i.e. beaks) and some have elongated neural spines (i.e. sails). However, the timing and acquisition of these character states is unknown given the uncertainty of the skull morphology of the ‘mid-grade’ poposauroid P. gracilis. Here, we present the first confirmed skull remains of P. gracilis directly associated with diagnostic pelvic elements that overlap with the holotype. The incomplete skeleton (PEFO 34865) from the Chinle Formation of Petrified Forest National Park (Arizona, USA) includes a left maxilla with a large, mediolaterally compressed tooth, left dentary, right prearticular and a partial postcranium. The character states of P. gracilis (bipedal, ‘sail-less’ and toothed) demonstrate that the evolution of bipedalism, the origin/loss of a dorsal ‘sail’ and the shift to an edentulous beak are complex in poposauroids. P. gracilis is widespread in the Upper Triassic formations in the western USA and is restricted temporally prior to the Adamanian–Revueltian faunal turnover during the Norian.

Description: The first large (〉1 m) diapsids appeared near the Permian–Triassic extinction and a subset of diapsids, the archosauriforms, expanded their body size range soon after in the Early–Middle Triassic. Here, we examine body size at key evolutionary events within Archosauriformes during the Triassic and through the end-Triassic extinction. Using femoral length as a body size proxy and a temporally calibrated phylogeny of Archosauriformes, we estimate ancestral body sizes using a maximum likelihood approach and test for the presence of an adapative radiation by comparing the fit of competing evolutionary models. Archosauriform body size is characterized by punctuated change with more change occurring early in the Triassic. Archosaurs crossing the Triassic–Jurassic boundary show a wide range in ancestral size, and dinosaurs (sauropodomorphs and theropods) are considerably larger in the Jurassic. Crocodylomorph origins are characterized by a drop in body size; however, both the relative amount of change and the rate of change are matched among other archosaur clades. Archosauriforms increase in absolute body size through the Triassic and evidence suggests that a directional trend in size increase occurred in the early Mesozoic. The morphological signature of adaptive radiation is rare in comparative data from extant animals but is present at the origination of Archosauriformes.

Description: Archosauromorphs radiated into numerous trophic niches during the Mesozoic, many of which were accommodated by particular suites of cranial adaptations and feeding behaviours. The mandibular symphysis, the joint linking the mandibles, is a poorly understood craniomandibular joint that may offer significant insight into skull function and feeding ecology. Using comparative data from extant amniotes, we investigated the skeletal anatomy and osteological correlates of relevant soft tissues in a survey of archosauromorph mandibular symphyses. Characters were identified and their evolution mapped using a current phylogeny of archosauriforms with the addition of non-archosauriform archosauromorphs. Extinct taxa with the simple Class I condition (e.g. proterochampsids, ‘rauisuchians’), rugose Class II (aetosaurs, protosuchians, silesaurids) and interdigitating Class III symphyses (e.g. phytosaurs, crocodyliforms) and finally fused Class IV (avians) build the joints in expected ways, although they differ in the contributions of bony elements and Meckel’s cartilage. Optimization of the different classes of symphyses across archosauromorph clades indicates that major iterative transitions from plesiomorphic Class I to derived, rigid Class II–IV symphyses occurred along the lines to phytosaurs, aetosaurs, a subset of poposauroids, crocodyliformes, pterosaurs and birds. These transitions in symphyseal morphology also appear to track changes in dentition and potentially diet.

Description: We present the first comprehensive description of Prorotodactylus and Rotodactylus dinosauromorph tracks from the Early and Middle Triassic of the Holy Cross Mountains, Poland. We describe and comprehensively figure tracks that have been mentioned briefly in previous accounts as well as new, recently discovered material, and analyse the variation and stratigraphic distribution of these specimens. Tracks have been recorded from four sites – Koszary, Stryczowice, Wióry and Baranów – which span the early Olenekian–early Anisian (c. 250–246 Ma). These tracks therefore represent an ichnological record of the evolutionary succession of early dinosauromorphs during the earliest part of their evolutionary history. Recognized track types include cf. Prorotodactylus isp., Prorotodactylus isp., Prorotodactylus mirus, Rotodactylus cursorius, Rotodactylus isp. and cf. Rotodactylus isp. At least three distinct Early and early Middle Triassic early dinosauromorph ichnofaunas can be recognized. The oldest, which is early Olenekian in age, is characterized by the presence of Prorotodactylus isp., cf. Prorotodactylus isp. and non-archosaurian archosauromorph or archosaur tracks (e.g. Synaptichnium isp., Protochirotherium isp.), recorded at the Stryczowice and Koszary sites. The following assemblage, recorded at the late Olenekian Wióry site, displays the highest ichnodiversity of dinosauromorphs, with four track types present (Prorotodactylus isp., Prorotodactylus mirus, Rotodactylus cursorius and cf. Rotodactylus isp.). The youngest site, Baranów, includes Rotodactylus isp., as well as other larger dinosauromorph tracks. The first body fossil evidence of dinosauromorphs is a few million years younger than the youngest Polish tracks, so Prorotodactylus and Rotodactylus tracks currently provide the oldest record of dinosauromorph morphology, biology and evolution.

Description: Marine inundation hazards in French Polynesia are various and unevenly distributed in the territory; they are strongly related to the physiography (topography, bathymetry, coral reef development) of these oceanic islands. Cyclones and tsunamis appear as predominant processes in the definition of coastal flooding risks for Polynesian people. This study examines the geomorphic impacts of Tropical Cyclone Oli, which struck the western part of French Polynesia in February 2010. Submarine reef erosion is quantified through coral colony degree of destruction and massive coral colony displacement. Sediment transport and beach retreat are quantified, and flow velocities at the coastline are estimated through boulder analysis. Erosion and resilience of a sandy bank (cay) at the reef margin is also considered on Tubuai Island through satellite image analysis and GPS field survey. Outer-reef slope angle appears as a major control factor for coral destruction, with vertical submarine cliffs relatively shielded compared to gentle slopes. Submarine boulder measurements provide valuable estimates of flow velocity profile with depth. Beachrock slab measurements also provide estimates of flow velocities at the reef–beach junction. Combining these different geomorphic markers might be a way to apprehend the flow velocity variation when the cyclone waves cross the coral reef.

Description: In the past few years, large earthquakes and torrential rain hit southern Taiwan and induced severe submarine hazards off the SW coast. Marine sediments (turbidites) provide valuable records with which to study and understand the formation of these submarine geo-hazards. The Pingtung Earthquake (two major events (ML=7.0) plus many aftershocks), on 26 December 2006, triggered turbidity currents that severed submarine cables in the Fangliao and Gaoping submarine canyons. This caused significant economic loss. In addition to earthquake activity, typhoons and torrential rains that induced flooding are also important mechanisms responsible for the formation of turbidites. On 8–9 August 2009 Typhoon Morakot brought heavy rains to southern Taiwan, causing serious landslides and flooding on land. The typhoon also caused submarine cable breaks in the Gaoping Canyon. All such events are likely to be recorded in the marine sediments of the canyon system, and by analysing these records we may be able to reconstruct the history of past earthquakes and floods in the region. Chirp sonar profiles, in conjunction with core analysis, including X-ray radiographs, grain size and 210Pb analysis, are used to identify the sources, transport and deposition of the turbidites (or hyperpycnite) and to reconstruct the history of earthquakes and flooding in the study area. Results indicate that these submarine hazards are not only related to earthquake and floods but that the unique geological and hydrological setting also plays an important role in the initiation of these submarine geo-hazards.

Description: The 2004 Indian Ocean tsunami deposited an extensive sandsheet on the coastal plain of SE India. At particular sites, the sedimentary bedding in the sandsheet provides evidence of variable energy conditions and flow during inundation of the coast. Trenching of the deposits at sites where only unidirectional flow was observed allowed the investigation of changes in hydrodynamics recorded in bedding structures without the added complexity of return flows and reworking. A high-velocity initial surge is recorded as upper flow regime (UFR) plane bedding. Following the initial high flow a period of falling flow velocity and quiescence occurs where sediments settle out of suspension, often resulting in a reverse graded bed that transitions to a graded (fining-up) bed. As water levels begin to decline after maximum inundation sheet flow caused the formation of inversely graded (coarsening-up) beds or a return to UFR conditions. At one site the final stages of tsunami inundation is recorded as small channels that have an erosional base and are filled with graded sediments that exhibit complex patterns of sedimentation. Pits excavated in areas of unidirectional flow allow the development of a sedimentary model for tsunami sediment dynamics across flat topography under unidirectional flow conditions.

Description: This paper examines communication methods used to inform the vulnerable community of Hilo, Hawaii of the impending tsunamis that struck in 1946 and 1960. These tsunamis caused tragic loss of life and enormous economic damage in Hilo and along the shores of the Hawaiian Island chain. Over 12 h notice of a possible large tsunami was given in 1960 and the siren warning system sounded more than 4 h prior to the event. The government agencies knew there was a tsunami alert and the media were broadcasting warnings. However, the 1960 tsunami took the lives of 61 people in Hilo only 14 years after 96 people were killed during the 1946 event. In order to discover why so many people perished, government agency logs recorded during the 1960 tsunami were examined and personal accounts from survivors of both the 1946 and 1960 tsunamis were analysed. Contributing to the tragic loss of life was a lack of communication between government agencies in addition to media inaccuracies and a public that was not educated in tsunami safety. Effective tsunami mitigation can only be accomplished through continual tsunami awareness education for the public, media and emergency personnel, and with accurate and timely tsunami warnings.