cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3454799.v1
title: Two-scale gravitational collapse in the Amazon Fan: a coupled system of gravity tectonics and mass-transport processes

description: Gravity tectonics affects the entire marine sedimentary sequence of the Foz do Amazonas basin, including the topmost Amazon Fan. During the various stages of the margin's evolution, the sedimentary loading and bathymetric slope induced the formation of a linked extensional–compressional system in which gravitational fold-and-thrust belts form significant structural features on the continental slope. Seismic analysis carried out in this study shows that sea-floor relief created along these thrust belts can trigger recurrent mass-transport deposits in the upper–middle Amazon Fan, suggesting a long-lasting linkage between gravity tectonics and mass-transport processes throughout the sedimentary evolution of the Amazon Fan.
DOI: 10.6084/m9.figshare.3454793
title: Dating the onset of Variscan crustal exhumation in the core of the Bohemian Massif: new U–Pb single zircon ages from the high-K calc-alkaline granodiorites of the Blatná suite, Central Bohemian Plutonic Complex

description: The Variscan Central Bohemian Plutonic Complex crops out between the upper-crustal Teplá–Barrandian and the high-grade Moldanubian units (Bohemian Massif). Much of the complex is made up of calc-alkaline plutonic rocks: (1) the geochemically more primitive, Na-rich 354 ± 4 Ma Sázava suite, which was emplaced syntectonically during regional shortening; (2) the younger, more evolved, potassic Blatná suite, which records both the shortening along its NW contact and the onset of normal shearing related to exhumation of the Moldanubian Unit to the SE. New ion microprobe U–Pb zircon ages for the high-K calc-alkaline Blatná suite pinpoint this major switch in the tectonic regime. Both Blatná and Kozárovice granodiorites (346 ± 2 Ma and 347 ± 2 Ma (2σ)) were generated by melting of heterogeneous crust and were emplaced contemporaneously to form the Blatná composite pluton. From age spectra preserved in inherited zircons and whole-rock Sr–Nd isotope signatures, the likely crustal sources for the magmas were immature greywackes rich in Neoproterozoic (615 ± 10 Ma, Kozárovice) or Late Cambrian–Early Ordovician (492 ± 4 Ma, Blatná) volcanogenic detritus. An additional important petrogenetic process was variable mixing with enriched mantle-derived monzonitic magmas, which may also have supplied the extra heat for crustal anatexis.
DOI: 10.6084/m9.figshare.3454793.v1
title: Dating the onset of Variscan crustal exhumation in the core of the Bohemian Massif: new U–Pb single zircon ages from the high-K calc-alkaline granodiorites of the Blatná suite, Central Bohemian Plutonic Complex

description: The Variscan Central Bohemian Plutonic Complex crops out between the upper-crustal Teplá–Barrandian and the high-grade Moldanubian units (Bohemian Massif). Much of the complex is made up of calc-alkaline plutonic rocks: (1) the geochemically more primitive, Na-rich 354 ± 4 Ma Sázava suite, which was emplaced syntectonically during regional shortening; (2) the younger, more evolved, potassic Blatná suite, which records both the shortening along its NW contact and the onset of normal shearing related to exhumation of the Moldanubian Unit to the SE. New ion microprobe U–Pb zircon ages for the high-K calc-alkaline Blatná suite pinpoint this major switch in the tectonic regime. Both Blatná and Kozárovice granodiorites (346 ± 2 Ma and 347 ± 2 Ma (2σ)) were generated by melting of heterogeneous crust and were emplaced contemporaneously to form the Blatná composite pluton. From age spectra preserved in inherited zircons and whole-rock Sr–Nd isotope signatures, the likely crustal sources for the magmas were immature greywackes rich in Neoproterozoic (615 ± 10 Ma, Kozárovice) or Late Cambrian–Early Ordovician (492 ± 4 Ma, Blatná) volcanogenic detritus. An additional important petrogenetic process was variable mixing with enriched mantle-derived monzonitic magmas, which may also have supplied the extra heat for crustal anatexis.
DOI: 10.6084/m9.figshare.3454784
title: Multiple high-pressure metamorphic events and crustal telescoping in the NW Highlands of Scotland

description: The Glenelg–Attadale Inlier is the largest basement inlier within the Caledonian orogen in NW Scotland. A Western Unit consists of trondhjemite–tonalite–granodiorite (TTG) gneisses and subordinate mafic intrusions with locally preserved mafic high-pressure granulite and eclogite assemblages. An Eastern Unit comprises TTG gneisses, Grenville-age (<em>c</em>. 1.1 Ga) eclogite and metasediments. U–Pb zircon ages from the Western Unit TTG gneisses are highly disturbed with Neoarchaean upper intercepts and Palaeo- to Mesoproterozoic lower intercepts, suggesting strong reworking at these times. U–Pb zircon, Sm–Nd and Lu–Hf garnet–clinopyroxene dates from the Western Unit high-pressure granulite and eclogite yield Neoarchaean (<em>c</em>. 2.6–2.8 Ga) and Palaeoproterozoic (<em>c</em>. 1.75 Ga) ages, respectively. These ages correspond to the ages of partial resetting of the TTG gneisses. The eclogite in the Western Unit may represent the high-pressure convergent margin to the lower-pressure Laxfordian events within the Lewisian Gneiss Complex, whereas the Mesoproterozoic eclogites in the Eastern Unit may represent a farther eastward Grenville-age margin. Further east, Ordovician high-pressure granulites within the Moine Supergroup may represent another, later, Grampian convergent margin. These high-pressure belts were developed sequentially towards the east and telescoped westwards from Palaeoproterozoic to Early Palaeozoic times.
DOI: 10.6084/m9.figshare.3454784.v1
title: Multiple high-pressure metamorphic events and crustal telescoping in the NW Highlands of Scotland

description: The Glenelg–Attadale Inlier is the largest basement inlier within the Caledonian orogen in NW Scotland. A Western Unit consists of trondhjemite–tonalite–granodiorite (TTG) gneisses and subordinate mafic intrusions with locally preserved mafic high-pressure granulite and eclogite assemblages. An Eastern Unit comprises TTG gneisses, Grenville-age (<em>c</em>. 1.1 Ga) eclogite and metasediments. U–Pb zircon ages from the Western Unit TTG gneisses are highly disturbed with Neoarchaean upper intercepts and Palaeo- to Mesoproterozoic lower intercepts, suggesting strong reworking at these times. U–Pb zircon, Sm–Nd and Lu–Hf garnet–clinopyroxene dates from the Western Unit high-pressure granulite and eclogite yield Neoarchaean (<em>c</em>. 2.6–2.8 Ga) and Palaeoproterozoic (<em>c</em>. 1.75 Ga) ages, respectively. These ages correspond to the ages of partial resetting of the TTG gneisses. The eclogite in the Western Unit may represent the high-pressure convergent margin to the lower-pressure Laxfordian events within the Lewisian Gneiss Complex, whereas the Mesoproterozoic eclogites in the Eastern Unit may represent a farther eastward Grenville-age margin. Further east, Ordovician high-pressure granulites within the Moine Supergroup may represent another, later, Grampian convergent margin. These high-pressure belts were developed sequentially towards the east and telescoped westwards from Palaeoproterozoic to Early Palaeozoic times.
DOI: 10.6084/m9.figshare.3454781
title: Spatial variations in biosphere <sup>87</sup>Sr/<sup>86</sup>Sr in Britain

description: Strontium isotopes are a powerful tool for investigating the geographical origins of people and animals but assignment of provenance requires reference maps and databases. This paper presents a map of strontium isotope variations across Britain for use in archaeological and other studies, and is produced by direct measurement of strontium isotope compositions of biosphere components, predominantly plants. The map characterizes the biosphere signature of specific lithologies: a technique that is applicable worldwide. Marine-derived strontium, from both rainwater and coastal sea-splash and spray, is an important contribution to the British biosphere, particularly on the western seaboard, which is subject to high rainfall and prevailing westerly winds.
DOI: 10.6084/m9.figshare.3454781.v1
title: Spatial variations in biosphere <sup>87</sup>Sr/<sup>86</sup>Sr in Britain

description: Strontium isotopes are a powerful tool for investigating the geographical origins of people and animals but assignment of provenance requires reference maps and databases. This paper presents a map of strontium isotope variations across Britain for use in archaeological and other studies, and is produced by direct measurement of strontium isotope compositions of biosphere components, predominantly plants. The map characterizes the biosphere signature of specific lithologies: a technique that is applicable worldwide. Marine-derived strontium, from both rainwater and coastal sea-splash and spray, is an important contribution to the British biosphere, particularly on the western seaboard, which is subject to high rainfall and prevailing westerly winds.
DOI: 10.6084/m9.figshare.3454778
title: Magnetotelluric characterization of a salt diapir: a case study on Bicorb–Quesa Diapir (Prebetic Zone, SE Spain)

description: The availability of geophysical data to determine the geometry at depth of a salt diapir and its surrounding structure is essential because of the complexity and changing geometry of these structures. For this purpose, potential field methods are commonly the first steps in subsurface exploration whereas seismic techniques are applied in later stages. However, the magnetotelluric method (MT) may fill the gap between the precision and the time that these two methods entail. To prove the usefulness of the MT method, it has been applied to the Bicorb–Quesa Diapir. This diapir is composed of evaporitic rocks piercing an overburden of carbonate rocks, providing a wide and contrasting range of electrical resistivity values. In this situation, the MT method may provide a coherent and realistic image of the subsurface. The application of the MT method has allowed us to (1) recognize a basement fault with a vertical throw of 1000 m, (2) elucidate the shape of the diapir, which is asymmetrical, with a north wall vertical and south wall dipping southwards, and (3) determine that all of the Late Triassic salt is concentrated in the diapir core.
DOI: 10.6084/m9.figshare.3454778.v1
title: Magnetotelluric characterization of a salt diapir: a case study on Bicorb–Quesa Diapir (Prebetic Zone, SE Spain)

description: The availability of geophysical data to determine the geometry at depth of a salt diapir and its surrounding structure is essential because of the complexity and changing geometry of these structures. For this purpose, potential field methods are commonly the first steps in subsurface exploration whereas seismic techniques are applied in later stages. However, the magnetotelluric method (MT) may fill the gap between the precision and the time that these two methods entail. To prove the usefulness of the MT method, it has been applied to the Bicorb–Quesa Diapir. This diapir is composed of evaporitic rocks piercing an overburden of carbonate rocks, providing a wide and contrasting range of electrical resistivity values. In this situation, the MT method may provide a coherent and realistic image of the subsurface. The application of the MT method has allowed us to (1) recognize a basement fault with a vertical throw of 1000 m, (2) elucidate the shape of the diapir, which is asymmetrical, with a north wall vertical and south wall dipping southwards, and (3) determine that all of the Late Triassic salt is concentrated in the diapir core.
DOI: 10.6084/m9.figshare.3454772
title: Pulsed emplacement of the Mount Kinabalu granite, northern Borneo

description: High-precision U–Pb ion microprobe analyses provide new constraints on the emplacement and origin of the Kinabalu granite in Sabah, northern Borneo. The granite is a sheeted laccolith-like body comprising dyke-fed granitic units that young downwards, each emplaced beneath the previous sheet. Analyses of concentric growth zones in zircons indicate crystallization between 7.85 ± 0.08 and 7.22 ± 0.07 Ma, and show that the entire pluton was emplaced and crystallized within less than 800 ka. Several pulses of magmatism are recognized, each lasting for a maximum of 250 ka, and possibly as briefly as 30 ka. The oldest ages coincide with the highest elevations whereas the youngest ages are found at lower elevations around the edge of the body. Based on these new age data and field observations we identify the biotite granodiorite, hornblende granite and porphyritic facies as the Upper, Middle and Lower Units respectively. Inherited zircon ages indicate different protoliths for the Upper and Middle Units. The Upper Unit is derived from attenuated continental crust of the South China margin subducted beneath Sabah. The Middle Unit is sourced from melting of the crystalline basement in Sabah with little or no contribution from South China crust.
DOI: 10.6084/m9.figshare.3454772.v1
title: Pulsed emplacement of the Mount Kinabalu granite, northern Borneo

description: High-precision U–Pb ion microprobe analyses provide new constraints on the emplacement and origin of the Kinabalu granite in Sabah, northern Borneo. The granite is a sheeted laccolith-like body comprising dyke-fed granitic units that young downwards, each emplaced beneath the previous sheet. Analyses of concentric growth zones in zircons indicate crystallization between 7.85 ± 0.08 and 7.22 ± 0.07 Ma, and show that the entire pluton was emplaced and crystallized within less than 800 ka. Several pulses of magmatism are recognized, each lasting for a maximum of 250 ka, and possibly as briefly as 30 ka. The oldest ages coincide with the highest elevations whereas the youngest ages are found at lower elevations around the edge of the body. Based on these new age data and field observations we identify the biotite granodiorite, hornblende granite and porphyritic facies as the Upper, Middle and Lower Units respectively. Inherited zircon ages indicate different protoliths for the Upper and Middle Units. The Upper Unit is derived from attenuated continental crust of the South China margin subducted beneath Sabah. The Middle Unit is sourced from melting of the crystalline basement in Sabah with little or no contribution from South China crust.
DOI: 10.6084/m9.figshare.3454769
title: Correlation of Ordovician diamictites from Argentina and South Africa using detrital zircon dating

description: The results of detrital zircon U–Pb geochronology suggest a maximum depositional age of 485 ± 7.2 Ma for a glacial diamictite from the Sierra del Volcán in eastern Argentina (Tandilia System). Earlier interpretations associated the deposit with the Neoproterozoic ‘snowball Earth' hypothesis. The data allow direct correlation, for the first time, between Early Palaeozoic deposits in both South America and South Africa connecting the glacial deposits from southern Bolivia to central Argentina with those in South Africa (Pakhuis Formation). On the basis of these results, a new distribution map of glacial cover, corresponding to the Hirnantian stage, can be developed.
DOI: 10.6084/m9.figshare.3454769.v1
title: Correlation of Ordovician diamictites from Argentina and South Africa using detrital zircon dating

description: The results of detrital zircon U–Pb geochronology suggest a maximum depositional age of 485 ± 7.2 Ma for a glacial diamictite from the Sierra del Volcán in eastern Argentina (Tandilia System). Earlier interpretations associated the deposit with the Neoproterozoic ‘snowball Earth' hypothesis. The data allow direct correlation, for the first time, between Early Palaeozoic deposits in both South America and South Africa connecting the glacial deposits from southern Bolivia to central Argentina with those in South Africa (Pakhuis Formation). On the basis of these results, a new distribution map of glacial cover, corresponding to the Hirnantian stage, can be developed.
DOI: 10.6084/m9.figshare.3454763
title: Anatomy, age and evolution of a collisional mountain belt: the Baltoro granite batholith and Karakoram Metamorphic Complex, Pakistani Karakoram

description: Geological mapping and U–(Th)–Pb geochronology from the Karakoram Metamorphic Complex and Baltoro granite batholith has resulted in more detailed timing constraints on tectonic evolution of Asian crust. During and following collision and accretion of the Kohistan Arc and the Indian plate to the southern margin of Asia, crustal thickening along the Karakoram resulted in polyphase deformation, metamorphism and melting. U–Pb zircon and monazite ages show that kyanite- and sillimanite-grade metamorphism in the Baltoro region peaked during Oligocene–Early Miocene (<em>c</em>. 28–22 Ma) times. At structurally deeper levels sillimanite-grade migmatites of the Dassu dome have Pliocene (<em>c</em>. 5.4–3.5 Ma) ages. New U–Pb ages from crustal melt biotite + muscovite + garnet leucogranites from the Trango Towers, Cathedral peak and Paiyu peak across the Baltoro batholith range from 19.8 ± 0.5 Ma to perhaps as young as 14 Ma. Using data from both the Hunza and Baltoro regions we suggest that regional high-grade metamorphism was diachronous in space and time and could have lasted continuously for at least 37 Ma (<em>c</em>. 50–13 Ma) or as much as 50 Ma (<em>c</em>. 63–13 Ma) along the southern margin of the Asian plate in the Karakoram. Crustal melting along the Baltoro granite batholith spanned at least 13 Ma (26.4–13 Ma).
DOI: 10.6084/m9.figshare.3454760
title: High-resolution dynamics of Early Jurassic marine extinctions: the case of Pliensbachian–Toarcian ammonites (Cephalopoda)

description: The Pliensbachian–Toarcian interval was marked by major environmental disturbances and by a second-order mass extinction. Here, we reappraise the taxonomic, spatiotemporal and selective dynamics of extinctions over the whole interval, by analysing a high-resolution dataset of 772 ammonite species from NW Tethyan and Arctic domains. On average, 40–65% of ammonite species disappeared during each subchronozone, but higher extinction pulses (reaching 70–90%) prevailed from the Margaritatus to the Dispansum Chronozone. The main extinctions, corresponding to the Gibbosus, Pliensbachian–Toarcian boundary, Semicelatum, Bifrons–Variabilis, and Dispansum events, differed in their dynamics, suggesting episodes of ecological stress related to climate change, regression, disturbance in the carbon cycle or anoxia. The multi-pulsed volcanic activity in the Karoo–Ferrar province could well have triggered these ecological changes. In addition, ammonites experienced a morphological bottleneck during the Gibbosus event, 1 Ma before the Early Toarcian diversity collapse. Typically, drops in richness were related both to high extinctions and to declines in origination rates. This feature could result from strengthened ecological stresses related to the temporal overlap of environmental disturbances. After the Early Toarcian crisis, the recovery of ammonites was rapid (2 Ma) and probably influenced by a coeval marine transgression.
DOI: 10.6084/m9.figshare.3454760.v1
title: High-resolution dynamics of Early Jurassic marine extinctions: the case of Pliensbachian–Toarcian ammonites (Cephalopoda)

description: The Pliensbachian–Toarcian interval was marked by major environmental disturbances and by a second-order mass extinction. Here, we reappraise the taxonomic, spatiotemporal and selective dynamics of extinctions over the whole interval, by analysing a high-resolution dataset of 772 ammonite species from NW Tethyan and Arctic domains. On average, 40–65% of ammonite species disappeared during each subchronozone, but higher extinction pulses (reaching 70–90%) prevailed from the Margaritatus to the Dispansum Chronozone. The main extinctions, corresponding to the Gibbosus, Pliensbachian–Toarcian boundary, Semicelatum, Bifrons–Variabilis, and Dispansum events, differed in their dynamics, suggesting episodes of ecological stress related to climate change, regression, disturbance in the carbon cycle or anoxia. The multi-pulsed volcanic activity in the Karoo–Ferrar province could well have triggered these ecological changes. In addition, ammonites experienced a morphological bottleneck during the Gibbosus event, 1 Ma before the Early Toarcian diversity collapse. Typically, drops in richness were related both to high extinctions and to declines in origination rates. This feature could result from strengthened ecological stresses related to the temporal overlap of environmental disturbances. After the Early Toarcian crisis, the recovery of ammonites was rapid (2 Ma) and probably influenced by a coeval marine transgression.
DOI: 10.6084/m9.figshare.3454754
title: Evidence for 930 Ma metamorphism in the Shetland Islands, Scottish Caledonides: implications for Neoproterozoic tectonics in the Laurentia–Baltica sector of Rodinia

description: Zircon and monazite laser-ablation inductively coupled plasma mass spectrometry U–Pb geochronological data for two metasediment samples from the Westing Group, northern Shetland Islands, Scottish Caledonides yield ages between 938 ± 8 and 925 ± 10 Ma (Tonian) for upper amphibolites-facies metamorphism. Texturally early metamorphism is recorded by a migmatitic garnet + sillimanite + plagioclase + muscovite + biotite assemblage, which formed at <em>c</em>. 650–700 °C and 7 kbar. Subsequent reworking resulted in the growth of a secondary garnet + kyanite + plagioclase + muscovite + biotite assemblage at <em>c</em>. 650 °C and 8–9 kbar. <em>In situ</em> electron probe microanalysis (EPMA) U–Th–Pb chemical dating of monazite hosted within garnet grains and the matrix of one sample also give Tonian ages, apparently indicating that all the metamorphism occurred during the Neoproterozoic. However, the dominant structural fabrics appear to have formed during the Ordovician–Silurian Caledonian orogeny, suggesting that the reworking was substantially younger despite the apparent absence of Caledonian monazite or zircon ages. Detrital zircons are consistent with Laurentia–Baltica provenance. Deposition of the Westing Group is constrained to between <em>c</em>. 1030 and 930 Ma. The timing of Tonian metamorphism suggests possible correlations with sequences elsewhere in the northern Caledonides, including the Krummedal Succession of East Greenland and Laurentian-derived successions in Svalbard and northern Norway.
DOI: 10.6084/m9.figshare.3454754.v1
title: Evidence for 930 Ma metamorphism in the Shetland Islands, Scottish Caledonides: implications for Neoproterozoic tectonics in the Laurentia–Baltica sector of Rodinia

description: Zircon and monazite laser-ablation inductively coupled plasma mass spectrometry U–Pb geochronological data for two metasediment samples from the Westing Group, northern Shetland Islands, Scottish Caledonides yield ages between 938 ± 8 and 925 ± 10 Ma (Tonian) for upper amphibolites-facies metamorphism. Texturally early metamorphism is recorded by a migmatitic garnet + sillimanite + plagioclase + muscovite + biotite assemblage, which formed at <em>c</em>. 650–700 °C and 7 kbar. Subsequent reworking resulted in the growth of a secondary garnet + kyanite + plagioclase + muscovite + biotite assemblage at <em>c</em>. 650 °C and 8–9 kbar. <em>In situ</em> electron probe microanalysis (EPMA) U–Th–Pb chemical dating of monazite hosted within garnet grains and the matrix of one sample also give Tonian ages, apparently indicating that all the metamorphism occurred during the Neoproterozoic. However, the dominant structural fabrics appear to have formed during the Ordovician–Silurian Caledonian orogeny, suggesting that the reworking was substantially younger despite the apparent absence of Caledonian monazite or zircon ages. Detrital zircons are consistent with Laurentia–Baltica provenance. Deposition of the Westing Group is constrained to between <em>c</em>. 1030 and 930 Ma. The timing of Tonian metamorphism suggests possible correlations with sequences elsewhere in the northern Caledonides, including the Krummedal Succession of East Greenland and Laurentian-derived successions in Svalbard and northern Norway.