cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3452930.v2
title: Geochemistry of 24 Ma basalts from NE Egypt: source components and fractionation history

description: Subalkaline basalts from NE Egypt represent an episode of magmatism at <em>c</em>. 24 Ma, coincident with widespread eruptive activity in northern Africa. New geochemical data provide insight into the mineralogical and isotopic characteristics of the underlying mantle. The basalts show little geochemical variation, with incompatible trace element abundances similar to those of ocean island basalts. They display fairly smooth primitive mantle-normalized incompatible trace element patterns. Trace element abundances and Sr–Nd–Pb–Hf isotopic signatures are consistent with contributions from two distinct source regions, one similar to the Afar plume and the other located within the metasomatized spinel-facies subcontinental lithosphere. Mixing of melts from these two domains was followed by minor crustal contamination during prolonged ascent or emplacement. Integrating the geochemical data with available tomographic information allows us to develop a framework for understanding mid-Tertiary magmatic activity throughout northern Africa. A model for this widespread volcanism involves ascent of upwelling mantle derived from the margins of the South African Superplume rooted at the core–mantle boundary and/or through small-scale convection at the 660 km discontinuity. Ascent of magmas to the surface was facilitated by pre-existing structures within the lithosphere, including those associated with incipient rifting of the Red Sea.
DOI: 10.6084/m9.figshare.3452930.v1
title: Geochemistry of 24 Ma basalts from NE Egypt: source components and fractionation history

description: Subalkaline basalts from NE Egypt represent an episode of magmatism at <em>c</em>. 24 Ma, coincident with widespread eruptive activity in northern Africa. New geochemical data provide insight into the mineralogical and isotopic characteristics of the underlying mantle. The basalts show little geochemical variation, with incompatible trace element abundances similar to those of ocean island basalts. They display fairly smooth primitive mantle-normalized incompatible trace element patterns. Trace element abundances and Sr–Nd–Pb–Hf isotopic signatures are consistent with contributions from two distinct source regions, one similar to the Afar plume and the other located within the metasomatized spinel-facies subcontinental lithosphere. Mixing of melts from these two domains was followed by minor crustal contamination during prolonged ascent or emplacement. Integrating the geochemical data with available tomographic information allows us to develop a framework for understanding mid-Tertiary magmatic activity throughout northern Africa. A model for this widespread volcanism involves ascent of upwelling mantle derived from the margins of the South African Superplume rooted at the core–mantle boundary and/or through small-scale convection at the 660 km discontinuity. Ascent of magmas to the surface was facilitated by pre-existing structures within the lithosphere, including those associated with incipient rifting of the Red Sea.
DOI: 10.6084/m9.figshare.3452927
title: The deep-sea microfossil record of macroevolutionary change in plankton and its study

description: The deep-sea planktonic microfossil record (foraminifera, coccolithophores, diatoms, radiolaria and dinoflagellates) provides a unique resource for palaeobiology. Despite some geographical gaps due to poor regional preservation, and intermittant time intervals lost to erosion, most time periods for each Cenozoic planktonic biogeographical province are preserved. Vast numbers of specimens and numerous deep-sea cores provide abundant material and the opportunity to tightly integrate macroevolutionary and palaeoenvironmental data. Current documentation of this record is mixed. Catalogues for foraminifera and coccolithophores offer nearly complete species-level clade histories, but taxonomy for siliceous microfossils is incomplete. Published occurrence data is primarily stratigraphic and covers only a fraction of the total preserved diversity. Age models for some sections are excellent (accuracy <em>c</em>. 100 kya) but for many other sections are still poor. Taxonomic errors, age model errors and reworking displace fossil occurrences in time, complicating palaeobiological analysis. With additional taxonomic work, careful collection of whole fauna/floral assemblage occurrence data, improved age models, and the development of better data filtering and analysis tools to deal with data outliers the deep-sea microfossil record can deliver its promise of providing the most complete, detailed record of macroevolutionary change available to science.
DOI: 10.6084/m9.figshare.3452927.v1
title: The deep-sea microfossil record of macroevolutionary change in plankton and its study

description: The deep-sea planktonic microfossil record (foraminifera, coccolithophores, diatoms, radiolaria and dinoflagellates) provides a unique resource for palaeobiology. Despite some geographical gaps due to poor regional preservation, and intermittant time intervals lost to erosion, most time periods for each Cenozoic planktonic biogeographical province are preserved. Vast numbers of specimens and numerous deep-sea cores provide abundant material and the opportunity to tightly integrate macroevolutionary and palaeoenvironmental data. Current documentation of this record is mixed. Catalogues for foraminifera and coccolithophores offer nearly complete species-level clade histories, but taxonomy for siliceous microfossils is incomplete. Published occurrence data is primarily stratigraphic and covers only a fraction of the total preserved diversity. Age models for some sections are excellent (accuracy <em>c</em>. 100 kya) but for many other sections are still poor. Taxonomic errors, age model errors and reworking displace fossil occurrences in time, complicating palaeobiological analysis. With additional taxonomic work, careful collection of whole fauna/floral assemblage occurrence data, improved age models, and the development of better data filtering and analysis tools to deal with data outliers the deep-sea microfossil record can deliver its promise of providing the most complete, detailed record of macroevolutionary change available to science.
DOI: 10.6084/m9.figshare.3452924
title: Palaeoposition of the Seychelles microcontinent in relation to the Deccan Traps and the Plume Generation Zone in Late Cretaceous-Early Palaeogene time

description: The Early Palaeogene magmatic rocks of North and Silhouette Islands in the Seychelles contain clues to the Cenozoic geodynamic puzzle of the Indian Ocean, but have so far lacked precise geochronological data and palaeomagnetic constraints. New <sup>40</sup>Ar/<sup>39</sup>Ar and U–Pb dates demonstrate that these rocks were emplaced during magnetochron C28n; however, <sup>40</sup>Ar/<sup>39</sup>Ar and palaeomagnetic data from Silhouette indicate that this complex experienced a protracted period of cooling. The Seychelles palaeomagnetic pole (57.55°S and 114.22°E; A9512.3°, <em>N</em>=14) corresponds to poles of similar ages from the Deccan Traps after being corrected for a clockwise rotation of 29.4°±12.9°. This implies that Seychelles acted as an independent microplate between the Indian and African plates during and possibly after C27r time, confirming recent results based on kinematic studies. Our reconstruction confirms that the eruption of the Deccan Traps, which affected both India and the Seychelles and triggered continental break-up, can be linked to the present active Reunion hotspot, which is being sourced as a deep plume from the Plume Generation Zone.
DOI: 10.6084/m9.figshare.3452924.v1
title: Palaeoposition of the Seychelles microcontinent in relation to the Deccan Traps and the Plume Generation Zone in Late Cretaceous-Early Palaeogene time

description: The Early Palaeogene magmatic rocks of North and Silhouette Islands in the Seychelles contain clues to the Cenozoic geodynamic puzzle of the Indian Ocean, but have so far lacked precise geochronological data and palaeomagnetic constraints. New <sup>40</sup>Ar/<sup>39</sup>Ar and U–Pb dates demonstrate that these rocks were emplaced during magnetochron C28n; however, <sup>40</sup>Ar/<sup>39</sup>Ar and palaeomagnetic data from Silhouette indicate that this complex experienced a protracted period of cooling. The Seychelles palaeomagnetic pole (57.55°S and 114.22°E; A9512.3°, <em>N</em>=14) corresponds to poles of similar ages from the Deccan Traps after being corrected for a clockwise rotation of 29.4°±12.9°. This implies that Seychelles acted as an independent microplate between the Indian and African plates during and possibly after C27r time, confirming recent results based on kinematic studies. Our reconstruction confirms that the eruption of the Deccan Traps, which affected both India and the Seychelles and triggered continental break-up, can be linked to the present active Reunion hotspot, which is being sourced as a deep plume from the Plume Generation Zone.
DOI: 10.6084/m9.figshare.3452921
title: Chapter 70 The Elatina glaciation (late Cryogenian), South Australia

description: Deposits of the late Cryogenian Elatina glaciation constitute the Yerelina Subgroup in the Adelaide Geosyncline region, South Australia. They have a maximum thickness of <em>c</em>. 1500 m, cover 200 000 km<sup>2</sup>, and include the following facies: basal boulder diamictite with penetrative glaciotectonites affecting preglacial beds; widespread massive and stratified diamictites containing faceted and striated clasts, some derived from nearby emergent diapiric islands and others of extrabasinal provenance; laminated siltstone and mudstone with dropstones; tidalites and widespread glaciofluvial, deltaic to marine-shelf sandstones; a regolith of frost-shattered quartzite breccia up to 20 m thick that contains primary sand wedges 3+ m deep and other large-scale periglacial forms; and an aeolian sand sheet covering 25 000 km<sup>2</sup> and containing primary sand wedges near its base. These deposits mark a spectrum of settings ranging from permafrost regolith and periglacial aeolian on the cratonic platform (Stuart Shelf) in the present west, through glaciofluvial, marginal-marine and inner marine-shelf in the central parts of the Adelaide Geosyncline, to outer marine-shelf in sub-basins in the present SE and north. The Elatina glaciation has not been dated directly, and only maximum and minimum age limits of <em>c</em>. 640 and 580 Ma, respectively, are indicated. Palaeomagnetic data for red beds from the Elatina Formation (Fm.) and associated strata indicate deposition of the Yerelina Subgroup within 10° of the palaeoequator. The Yerelina Subgroup is unconformably to disconformably overlain by the dolomitic Nuccaleena Fm., which in most places is the lowest unit of the Wilpena Group and marks Early Ediacaran marine transgression.
DOI: 10.6084/m9.figshare.3452921.v1
title: Chapter 70 The Elatina glaciation (late Cryogenian), South Australia

description: Deposits of the late Cryogenian Elatina glaciation constitute the Yerelina Subgroup in the Adelaide Geosyncline region, South Australia. They have a maximum thickness of <em>c</em>. 1500 m, cover 200 000 km<sup>2</sup>, and include the following facies: basal boulder diamictite with penetrative glaciotectonites affecting preglacial beds; widespread massive and stratified diamictites containing faceted and striated clasts, some derived from nearby emergent diapiric islands and others of extrabasinal provenance; laminated siltstone and mudstone with dropstones; tidalites and widespread glaciofluvial, deltaic to marine-shelf sandstones; a regolith of frost-shattered quartzite breccia up to 20 m thick that contains primary sand wedges 3+ m deep and other large-scale periglacial forms; and an aeolian sand sheet covering 25 000 km<sup>2</sup> and containing primary sand wedges near its base. These deposits mark a spectrum of settings ranging from permafrost regolith and periglacial aeolian on the cratonic platform (Stuart Shelf) in the present west, through glaciofluvial, marginal-marine and inner marine-shelf in the central parts of the Adelaide Geosyncline, to outer marine-shelf in sub-basins in the present SE and north. The Elatina glaciation has not been dated directly, and only maximum and minimum age limits of <em>c</em>. 640 and 580 Ma, respectively, are indicated. Palaeomagnetic data for red beds from the Elatina Formation (Fm.) and associated strata indicate deposition of the Yerelina Subgroup within 10° of the palaeoequator. The Yerelina Subgroup is unconformably to disconformably overlain by the dolomitic Nuccaleena Fm., which in most places is the lowest unit of the Wilpena Group and marks Early Ediacaran marine transgression.
DOI: 10.6084/m9.figshare.3452918
title: Chapter 44 The Chiquerío Formation, southern Peru

description: The Chiquerío Formation (Fm.) is a thick glaciogenic succession deposited unconformably on gneisses of the Arequipa massif in southern Peru. It has undergone greenschist facies metamorphism during Early Palaeozoic orogenesis. The Chiquerío Fm. consists of nearly 400 m of diamictite, sandstone, mudstone and carbonate, with a thin (11 m) cap dolostone at the top of the formation. It is overlain by the San Juan Fm., a 2-km-thick carbonate succession. The thick glacially influenced succession was deposited in deep marine conditions and consists mainly of massive diamictites (representing either ice-rafted debris or submarine debris flows) interbedded with turbiditic sandstones. Where internal lamination is present (e.g. bedding in the turbiditic packages), abundant dropstones can be recognized. There is no evidence of shallow marine reworking of the succession. No absolute age constraints on the depositional timing of the Chiquerío Fm. exist, because no volcanic tuffs have yet been identified. U–Pb dating of detrital zircons (U–Th–Pb SIMS) from the Chiquerío Fm. and the overlying San Juan Fm. suggest it is autochthonous with respect to Amazonia, as the detrital zircon age spectra suggest derivation from the Amazonian craton. Detrital grains as young as <em>c.</em> 700 Ma have been documented in the post-glacial San Juan Fm. The sparse (chemo)stratigraphic data available for the Chiquerío Fm. exhibit patterns similar to those observed generally in Neoproterozoic post-glacial carbonate sequences. Palaeogeographic models for the deposition of the Chiquerío Fm. are critically dependent on the timing of the docking of the basement of the Arequipa massif with the South American craton (Amazonia). Presently there are no palaeomagnetic constraints. More research on the chronological and palaeogeographical constraints of this succession is required.
DOI: 10.6084/m9.figshare.3452918.v1
title: Chapter 44 The Chiquerío Formation, southern Peru

description: The Chiquerío Formation (Fm.) is a thick glaciogenic succession deposited unconformably on gneisses of the Arequipa massif in southern Peru. It has undergone greenschist facies metamorphism during Early Palaeozoic orogenesis. The Chiquerío Fm. consists of nearly 400 m of diamictite, sandstone, mudstone and carbonate, with a thin (11 m) cap dolostone at the top of the formation. It is overlain by the San Juan Fm., a 2-km-thick carbonate succession. The thick glacially influenced succession was deposited in deep marine conditions and consists mainly of massive diamictites (representing either ice-rafted debris or submarine debris flows) interbedded with turbiditic sandstones. Where internal lamination is present (e.g. bedding in the turbiditic packages), abundant dropstones can be recognized. There is no evidence of shallow marine reworking of the succession. No absolute age constraints on the depositional timing of the Chiquerío Fm. exist, because no volcanic tuffs have yet been identified. U–Pb dating of detrital zircons (U–Th–Pb SIMS) from the Chiquerío Fm. and the overlying San Juan Fm. suggest it is autochthonous with respect to Amazonia, as the detrital zircon age spectra suggest derivation from the Amazonian craton. Detrital grains as young as <em>c.</em> 700 Ma have been documented in the post-glacial San Juan Fm. The sparse (chemo)stratigraphic data available for the Chiquerío Fm. exhibit patterns similar to those observed generally in Neoproterozoic post-glacial carbonate sequences. Palaeogeographic models for the deposition of the Chiquerío Fm. are critically dependent on the timing of the docking of the basement of the Arequipa massif with the South American craton (Amazonia). Presently there are no palaeomagnetic constraints. More research on the chronological and palaeogeographical constraints of this succession is required.
DOI: 10.6084/m9.figshare.3452915
title: Chapter 18 Geology and petroleum potential of the Timan–Pechora Basin Province, Russia

description: The Timan–Pechora Basin Province represents the northeastern-most cratonic block of Eastern European Russia. More than 16 billion barrels of oil (BBO) and 40 trillion cubic feet of gas (TCFG) have been discovered in this basin. Three geological assessment units (AU) were defined for assessing the potential for undiscovered oil and gas resources. The NW Izhma Depression AU encompasses all potential structures and reservoirs in the northwestern part of the Izhma–Pechora Depression, but this part of the basin contains little source and reservoir rocks and so was not assessed quantitatively. The Main Basin Platform AU includes all structures and reservoirs that developed in the central part of the basin where the tectonic evolution and development of petroleum systems were complex. The Foredeep Basins AU includes all potential reservoirs within the thick sedimentary section of the foredeep basins developed during the Permo-Triassic Uralian Orogeny. For the Timan–Pechora Basin Province, the estimated means of undiscovered resources are 3.3 BBO, 17 TCFG and 0.3 billion barrels of natural gas liquids (BBNGL). For the areas of the AUs north of the Arctic Circle in the Timan–Pechora Basin Province, the estimated means of undiscovered resources are 1.7 BBO, 9.0 TCFG and 0.2 BBNGL. The Pechora Sea was assessed with the South Barents Sea Province and is not included in this assessment.
DOI: 10.6084/m9.figshare.3452915.v1
title: Chapter 18 Geology and petroleum potential of the Timan–Pechora Basin Province, Russia

description: The Timan–Pechora Basin Province represents the northeastern-most cratonic block of Eastern European Russia. More than 16 billion barrels of oil (BBO) and 40 trillion cubic feet of gas (TCFG) have been discovered in this basin. Three geological assessment units (AU) were defined for assessing the potential for undiscovered oil and gas resources. The NW Izhma Depression AU encompasses all potential structures and reservoirs in the northwestern part of the Izhma–Pechora Depression, but this part of the basin contains little source and reservoir rocks and so was not assessed quantitatively. The Main Basin Platform AU includes all structures and reservoirs that developed in the central part of the basin where the tectonic evolution and development of petroleum systems were complex. The Foredeep Basins AU includes all potential reservoirs within the thick sedimentary section of the foredeep basins developed during the Permo-Triassic Uralian Orogeny. For the Timan–Pechora Basin Province, the estimated means of undiscovered resources are 3.3 BBO, 17 TCFG and 0.3 billion barrels of natural gas liquids (BBNGL). For the areas of the AUs north of the Arctic Circle in the Timan–Pechora Basin Province, the estimated means of undiscovered resources are 1.7 BBO, 9.0 TCFG and 0.2 BBNGL. The Pechora Sea was assessed with the South Barents Sea Province and is not included in this assessment.
DOI: 10.6084/m9.figshare.3452903
title: Age and composition of crystalline basement rocks on the Norwegian continental margin: offshore extension and continuity of the Caledonian–Appalachian orogenic belt

description: Twenty-two wells on the Norwegian continental margin have penetrated underlying basement. We present U–Pb zircon, whole-rock geochemical, and Sm–Nd and Rb–Sr isotopic data from nine wells in the North Sea and Norwegian Sea with relevance to the offshore continuation of the Norwegian Caledonides, and their correlation throughout the Caledonian–Appalachian orogenic belt. Palaeozoic magmatism in the North Sea can be divided into two groups. The older group consists of 460 Ma calc-alkaline granites with evolved isotopic compositions, correlative with similar rocks in the Uppermost Allochthon. The younger group consists of a 430 Ma dacite and a 421 Ma leucogabbro, with less evolved isotopic compositions. In the Norwegian Sea, isotopically evolved granitic magmatism at 437 Ma and more juvenile dioritic magmatism at 447 Ma are correlative with magmatism in the Bindal and Smøla–Hitra Batholiths in the Uppermost Allochthon. Metasedimentary basement rocks from the North Sea and Norwegian Sea, dominated by Late Palaeoproterozoic and Mesoproterozoic grains, resemble rocks found in the Caledonides of Scotland, Greenland and Svalbard. The new data, along with studies elsewhere along the belt, suggest that similar rocks may exist along much of the orogen.
DOI: 10.6084/m9.figshare.3452903.v1
title: Age and composition of crystalline basement rocks on the Norwegian continental margin: offshore extension and continuity of the Caledonian–Appalachian orogenic belt

description: Twenty-two wells on the Norwegian continental margin have penetrated underlying basement. We present U–Pb zircon, whole-rock geochemical, and Sm–Nd and Rb–Sr isotopic data from nine wells in the North Sea and Norwegian Sea with relevance to the offshore continuation of the Norwegian Caledonides, and their correlation throughout the Caledonian–Appalachian orogenic belt. Palaeozoic magmatism in the North Sea can be divided into two groups. The older group consists of 460 Ma calc-alkaline granites with evolved isotopic compositions, correlative with similar rocks in the Uppermost Allochthon. The younger group consists of a 430 Ma dacite and a 421 Ma leucogabbro, with less evolved isotopic compositions. In the Norwegian Sea, isotopically evolved granitic magmatism at 437 Ma and more juvenile dioritic magmatism at 447 Ma are correlative with magmatism in the Bindal and Smøla–Hitra Batholiths in the Uppermost Allochthon. Metasedimentary basement rocks from the North Sea and Norwegian Sea, dominated by Late Palaeoproterozoic and Mesoproterozoic grains, resemble rocks found in the Caledonides of Scotland, Greenland and Svalbard. The new data, along with studies elsewhere along the belt, suggest that similar rocks may exist along much of the orogen.