cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3453755.v1
title: Late Jurassic amphibolite-facies metamorphism in the Intra-Pontide Suture Zone (Turkey): an eastward extension of the Vardar Ocean from the Balkans into Anatolia?

description: The palaeogeography of Neotethys during its closure is still a matter of debate. This study provides new insights into the Neotethys closure by the discovery in the Intra-Pontide Suture Zone (Turkey) of an accretionary complex that recorded a Late Jurassic (<em>c</em>. 163 Ma) amphibolite-facies metamorphism. Results are discussed in the framework of the accretionary events that occurred at the southern margin of Laurasia. The resulting picture supports a new model in which the Vardar suture zone, in the Balkans, and the Intra-Pontide Suture Zone, in Anatolia, represent remnants of the same elongate oceanic basin.
DOI: 10.6084/m9.figshare.3453752
title: Reworking of old continental lithosphere: an important crustal evolution mechanism in orogenic belts, as evidenced by Triassic I-type granitoids in the East Kunlun orogen, Northern Tibetan Plateau

description: There is a strong genetic relationship between the petrogenesis of I-type granitoids and the evolution of continental crust in orogenic belts. This study of I-type granitoids in the East Kunlun orogen, Northern Tibetan Plateau, shows that reworking of old continental lithosphere is an important key to this genetic relationship. The East Kunlun has numerous Triassic granitic plutons that are related to subduction of the Palaeo-Tethyan ocean and terrane collision in the early Mesozoic. U–Pb analysis of zircons from these Triassic granitoids indicates that the granitic magmatism lasted from 249 to 223 Ma. Based on elemental and isotopic compositions and their petrogenesis, the magmatism can be divided into three groups. (1) Group 1 consists of quartz diorites and granodiorites (241–249 Ma), which are metaluminous high-K calc-alkaline I-type granitoids and exhibit typical subduction-related chemical characteristics. They were derived from lower crust mainly composed of Precambrian metabasaltic basement rocks with different degrees of involvement of mantle material. (2) Group 2 consists of granitic porphyries and syenogranites (231–238 Ma), which are high Rb/Sr, metaluminous to weakly peraluminous high-K alkali-calcic I-type granitoids, showing characteristics of typical pure crustal-derived granitoids. They were derived from partial melting of a Mesoproterozoic metagreywacke source in the lower crust. (3) Group 3 consists of porphyry granodiorites (<em>c</em>. 223 Ma), which are metaluminous high-K calc-alkaline I-type granitoids and exhibit the typical geochemical characteristics of adakites (e.g. high La/Yb and Sr/Y ratios and low Y and Yb contents). Their high K<sub>2</sub>O and low Mg# with evolved Sr–Nd–Hf isotopic compositions indicate that they were most probably derived from thickened mafic lower continental crust, which underwent partial melting induced by underplated hot mafic magma. Combining the present work with previous studies, we propose that the subduction of the Palaeo-Tethyan ocean lasted from 278 to 241 Ma, and the collision between the Bayan Har terrane and the East Kunlun occurred at 231–238 Ma, whereas the group 3 granitoids most probably formed in a post-collisional setting. Overall, all the studied I-type granitoids were derived from partial melting of old continental lower crust with minor addition of lithospheric mantle material; thus reworking of old continental lithosphere is an important mechanism for the evolution of orogenic crust.
DOI: 10.6084/m9.figshare.3453752.v1
title: Reworking of old continental lithosphere: an important crustal evolution mechanism in orogenic belts, as evidenced by Triassic I-type granitoids in the East Kunlun orogen, Northern Tibetan Plateau

description: There is a strong genetic relationship between the petrogenesis of I-type granitoids and the evolution of continental crust in orogenic belts. This study of I-type granitoids in the East Kunlun orogen, Northern Tibetan Plateau, shows that reworking of old continental lithosphere is an important key to this genetic relationship. The East Kunlun has numerous Triassic granitic plutons that are related to subduction of the Palaeo-Tethyan ocean and terrane collision in the early Mesozoic. U–Pb analysis of zircons from these Triassic granitoids indicates that the granitic magmatism lasted from 249 to 223 Ma. Based on elemental and isotopic compositions and their petrogenesis, the magmatism can be divided into three groups. (1) Group 1 consists of quartz diorites and granodiorites (241–249 Ma), which are metaluminous high-K calc-alkaline I-type granitoids and exhibit typical subduction-related chemical characteristics. They were derived from lower crust mainly composed of Precambrian metabasaltic basement rocks with different degrees of involvement of mantle material. (2) Group 2 consists of granitic porphyries and syenogranites (231–238 Ma), which are high Rb/Sr, metaluminous to weakly peraluminous high-K alkali-calcic I-type granitoids, showing characteristics of typical pure crustal-derived granitoids. They were derived from partial melting of a Mesoproterozoic metagreywacke source in the lower crust. (3) Group 3 consists of porphyry granodiorites (<em>c</em>. 223 Ma), which are metaluminous high-K calc-alkaline I-type granitoids and exhibit the typical geochemical characteristics of adakites (e.g. high La/Yb and Sr/Y ratios and low Y and Yb contents). Their high K<sub>2</sub>O and low Mg# with evolved Sr–Nd–Hf isotopic compositions indicate that they were most probably derived from thickened mafic lower continental crust, which underwent partial melting induced by underplated hot mafic magma. Combining the present work with previous studies, we propose that the subduction of the Palaeo-Tethyan ocean lasted from 278 to 241 Ma, and the collision between the Bayan Har terrane and the East Kunlun occurred at 231–238 Ma, whereas the group 3 granitoids most probably formed in a post-collisional setting. Overall, all the studied I-type granitoids were derived from partial melting of old continental lower crust with minor addition of lithospheric mantle material; thus reworking of old continental lithosphere is an important mechanism for the evolution of orogenic crust.
DOI: 10.6084/m9.figshare.3453740
title: Carbon isotopic evidence for organic matter oxidation in soils of the Old Red Sandstone (Silurian to Devonian, South Wales, UK)

description: Petrographic and calcrete carbon isotope data from seasonally waterlogged Upper Silurian (Přídolí) to Lower Devonian (Pragian) palaeo-Vertisols of the Old Red Sandstone, South Wales, UK, are presented. The δ<sup>13</sup>C values mostly range from −9 to −12‰ (VPDB), suggesting that the soils were inhabited by abundant vegetation that when oxidized (perhaps with microbial assistance) resulted in CO<sub>2</sub>-rich soils. Such soils would favour calcrete precipitation through equilibration of soil zone CO<sub>2</sub> with the relatively lower atmospheric <em>p</em>CO<sub>2</sub>. However, reliably estimating palaeoatmospheric <em>p</em>CO<sub>2</sub> using these carbon isotope data is a challenge.
DOI: 10.6084/m9.figshare.3453740.v1
title: Carbon isotopic evidence for organic matter oxidation in soils of the Old Red Sandstone (Silurian to Devonian, South Wales, UK)

description: Petrographic and calcrete carbon isotope data from seasonally waterlogged Upper Silurian (Přídolí) to Lower Devonian (Pragian) palaeo-Vertisols of the Old Red Sandstone, South Wales, UK, are presented. The δ<sup>13</sup>C values mostly range from −9 to −12‰ (VPDB), suggesting that the soils were inhabited by abundant vegetation that when oxidized (perhaps with microbial assistance) resulted in CO<sub>2</sub>-rich soils. Such soils would favour calcrete precipitation through equilibration of soil zone CO<sub>2</sub> with the relatively lower atmospheric <em>p</em>CO<sub>2</sub>. However, reliably estimating palaeoatmospheric <em>p</em>CO<sub>2</sub> using these carbon isotope data is a challenge.
DOI: 10.6084/m9.figshare.3453734
title: Hydrothermal fluids in epithermal and porphyry Au deposits in the Central Slovakia Volcanic Field

description: The Neogene Central Slovakia Volcanic Field in the Carpathian arc contains various Au deposits, hosted by central zones of large andesite stratovolcanoes. Fluids involved in mineralization have been studied at three different types of deposit, mostly by fluid inclusion and stable isotope techniques. The Rozália mine in the Štiavnica stratovolcano hosts intermediate sulphidation-style Au–Ag epithermal mineralization in subhorizontal veins related to hydrothermal activity during an early stage of caldera collapse. Associated fluids of low salinity underwent extensive boiling at 280–330 °C on transition from suprahydrostatic towards hydrodynamic conditions at shallow depths (<em>c.</em> 550 m) from fluids of mixed magmatic and meteoric origin. The Kremnica ore field hosts a large system of low sulphidation-style Au–Ag veins contemporaneous with rhyolite magmatism and situated on resurgent horst faults. Fluids were of low salinity, predominantly of meteoric origin, and showed gradual decrease in temperature along the system (<em>c.</em> 270–140 °C) related to a decrease in erosion level from <em>c.</em> 500 to <em>c.</em> 50 m. The Biely Vrch Au-porphyry deposit in the Javorie stratovolcano is associated with quartz stockwork in diorite porphyry intrusion. The major type of ore-bearing fluid was high temperature magmatic vapour (720–&lt;380 °C) accompanied by Fe-rich salt melt. Gold precipitated in a high-temperature but low-pressure subvolcanic environment.
DOI: 10.6084/m9.figshare.3453734.v1
title: Hydrothermal fluids in epithermal and porphyry Au deposits in the Central Slovakia Volcanic Field

description: The Neogene Central Slovakia Volcanic Field in the Carpathian arc contains various Au deposits, hosted by central zones of large andesite stratovolcanoes. Fluids involved in mineralization have been studied at three different types of deposit, mostly by fluid inclusion and stable isotope techniques. The Rozália mine in the Štiavnica stratovolcano hosts intermediate sulphidation-style Au–Ag epithermal mineralization in subhorizontal veins related to hydrothermal activity during an early stage of caldera collapse. Associated fluids of low salinity underwent extensive boiling at 280–330 °C on transition from suprahydrostatic towards hydrodynamic conditions at shallow depths (<em>c.</em> 550 m) from fluids of mixed magmatic and meteoric origin. The Kremnica ore field hosts a large system of low sulphidation-style Au–Ag veins contemporaneous with rhyolite magmatism and situated on resurgent horst faults. Fluids were of low salinity, predominantly of meteoric origin, and showed gradual decrease in temperature along the system (<em>c.</em> 270–140 °C) related to a decrease in erosion level from <em>c.</em> 500 to <em>c.</em> 50 m. The Biely Vrch Au-porphyry deposit in the Javorie stratovolcano is associated with quartz stockwork in diorite porphyry intrusion. The major type of ore-bearing fluid was high temperature magmatic vapour (720–&lt;380 °C) accompanied by Fe-rich salt melt. Gold precipitated in a high-temperature but low-pressure subvolcanic environment.
DOI: 10.6084/m9.figshare.3453731
title: Evidence for exsolution of Au-ore fluids from granites crystallized in the mid-crust, Archaean Louis Lake Batholith, Wyoming

description: The Louis Lake Batholith is contemporaneous with and sits adjacent to Archaean lode gold deposits and minor copper stockwork vein systems of the South Pass Greenstone Belt, Wyoming Province, and may thus have contributed fluid into these hydrothermal systems. The batholith is granodiorite to granite, lacks extreme fractionation, and contains evidence for early formation and later replacement of an immiscible early sulphide phase. Mafic enclaves contain anomalous concentrations of gold and copper, suggesting that metals were introduced from in-mixed mafic magma. Apatite SO<sub>3</sub> and Cl values imply relatively early exsolution of sulphur- and chlorine-bearing fluids during fractionation. Exsolution of possibly immiscible high- and low-salinity fluids is implied from fluid inclusion petrography, even though crystallization pressures were greater than 3 kbar. Low salinity inclusions share affinities with those of orogenic gold systems, but contain notably higher Pb and Zn concentrations. High salinity inclusions have similar elemental compositions to brines of intrusion-centred ore systems. It is proposed that sulphide melt separated early during magma fractionation, scavenging Au and Cu, but became later destabilized, possibly because of increased <em>f</em>O<sub>2</sub>, releasing scavenged metals. Metals were transported from the pluton in sulphur- and chlorine-bearing hydrothermal fluids of low and high salinity, with Au being preferentially transported in the low-salinity fluid.
DOI: 10.6084/m9.figshare.3453731.v1
title: Evidence for exsolution of Au-ore fluids from granites crystallized in the mid-crust, Archaean Louis Lake Batholith, Wyoming

description: The Louis Lake Batholith is contemporaneous with and sits adjacent to Archaean lode gold deposits and minor copper stockwork vein systems of the South Pass Greenstone Belt, Wyoming Province, and may thus have contributed fluid into these hydrothermal systems. The batholith is granodiorite to granite, lacks extreme fractionation, and contains evidence for early formation and later replacement of an immiscible early sulphide phase. Mafic enclaves contain anomalous concentrations of gold and copper, suggesting that metals were introduced from in-mixed mafic magma. Apatite SO<sub>3</sub> and Cl values imply relatively early exsolution of sulphur- and chlorine-bearing fluids during fractionation. Exsolution of possibly immiscible high- and low-salinity fluids is implied from fluid inclusion petrography, even though crystallization pressures were greater than 3 kbar. Low salinity inclusions share affinities with those of orogenic gold systems, but contain notably higher Pb and Zn concentrations. High salinity inclusions have similar elemental compositions to brines of intrusion-centred ore systems. It is proposed that sulphide melt separated early during magma fractionation, scavenging Au and Cu, but became later destabilized, possibly because of increased <em>f</em>O<sub>2</sub>, releasing scavenged metals. Metals were transported from the pluton in sulphur- and chlorine-bearing hydrothermal fluids of low and high salinity, with Au being preferentially transported in the low-salinity fluid.
DOI: 10.6084/m9.figshare.3453728
title: Thermotectonic history of SE China since the Late Mesozoic: insights from detailed thermochronological studies of Hong Kong

description: The late Mesozoic Yanshanian volcanic arc affected an extensive region of SE China, but the conclusion of magmatism and later evolution are not fully understood. Widespread Yanshanian ignimbrites and their contemporaneous granites exposed in Hong Kong represent a microcosm of this magmatic arc. To constrain the post-magmatic thermal history of the region, we present zircon and apatite fission-track analyses from these rocks. Double dating using laser ablation inductively coupled plasma mass spectrometry U–Pb and fission-track techniques on detrital zircons from post-volcanic Cretaceous sediments is used to further constrain the tectonothermal evolution. The resulting dataset and thermal modelling suggest that the igneous rocks and Cretaceous sediments together experienced post-emplacement or post-depositional heating to &gt;250 °C, subsequently cooling through 120–60 °C after <em>c</em>. 80 Ma. The heating reflects the combined effects of an enhanced geothermal gradient and burial. We interpret the enhanced gradient to represent continuing Yanshanian magmatic activity until <em>c</em>. 100–80 Ma, much later than previously considered. Our data also indicate a long-term, slow cooling (<em>c</em>. 1 °C myr<sup>–1</sup>) since the early Cenozoic, linked to <em>c</em>. 2–3 km of erosion-driven exhumation. The thermotectonic history of Hong Kong reflects the mid-Cretaceous transition of SE China from an active to a passive margin bordered by marginal basins that formed in the early Cenozoic.
DOI: 10.6084/m9.figshare.3453728.v1
title: Thermotectonic history of SE China since the Late Mesozoic: insights from detailed thermochronological studies of Hong Kong

description: The late Mesozoic Yanshanian volcanic arc affected an extensive region of SE China, but the conclusion of magmatism and later evolution are not fully understood. Widespread Yanshanian ignimbrites and their contemporaneous granites exposed in Hong Kong represent a microcosm of this magmatic arc. To constrain the post-magmatic thermal history of the region, we present zircon and apatite fission-track analyses from these rocks. Double dating using laser ablation inductively coupled plasma mass spectrometry U–Pb and fission-track techniques on detrital zircons from post-volcanic Cretaceous sediments is used to further constrain the tectonothermal evolution. The resulting dataset and thermal modelling suggest that the igneous rocks and Cretaceous sediments together experienced post-emplacement or post-depositional heating to &gt;250 °C, subsequently cooling through 120–60 °C after <em>c</em>. 80 Ma. The heating reflects the combined effects of an enhanced geothermal gradient and burial. We interpret the enhanced gradient to represent continuing Yanshanian magmatic activity until <em>c</em>. 100–80 Ma, much later than previously considered. Our data also indicate a long-term, slow cooling (<em>c</em>. 1 °C myr<sup>–1</sup>) since the early Cenozoic, linked to <em>c</em>. 2–3 km of erosion-driven exhumation. The thermotectonic history of Hong Kong reflects the mid-Cretaceous transition of SE China from an active to a passive margin bordered by marginal basins that formed in the early Cenozoic.
DOI: 10.6084/m9.figshare.3453725
title: Chapter 3 History of continental shelf and slope sedimentation on the US middle Atlantic margin

description: We describe sedimentation on the storm-dominated, microtidal, continental shelf and slope of the eastern US passive continental margin between the Hudson and Wilmington canyons. Sediments here recorded sea-level changes over the past 100 myr and provide a classic example of the interplay among eustasy, tectonism and sedimentation. Long-term margin evolution reflects changes in morphology from a Late Cretaceous–Eocene ramp to Oligocene and younger prograding clinothem geometries, a transition found on several other margins. Deltaic systems influenced Cretaceous and Miocene sedimentation, but, in general, the Maastrichtian–Palaeogene shelf was starved of sediment. Pre-Pleistocene sequences follow a repetitive model, with fining- and coarsening-upward successions associated with transgressions and regressions, respectively. Pleistocene–Holocene sequences are generally quite thin (&lt;20 m per sequence) and discontinuous beneath the modern shelf, reflecting starved sedimentation under high rates of eustatic change and low rates of subsidence. However, Pleistocene sequences can attain great thickness (hundreds of metres) beneath the outermost shelf and continental slope. Holocene sedimentation on the inner shelf reflects transgression, decelerating from rates of approximately 3–4 to around 2 mm a<sup>−1</sup> from 5 to 2 ka. Modern shelf sedimentation primarily reflects palimpsest sand sheets plastered and reworked into geostrophically controlled nearshore and shelf shore-oblique sand ridges, and does not provide a good analogue for pre-Pleistocene deposition.
DOI: 10.6084/m9.figshare.3453725.v1
title: Chapter 3 History of continental shelf and slope sedimentation on the US middle Atlantic margin

description: We describe sedimentation on the storm-dominated, microtidal, continental shelf and slope of the eastern US passive continental margin between the Hudson and Wilmington canyons. Sediments here recorded sea-level changes over the past 100 myr and provide a classic example of the interplay among eustasy, tectonism and sedimentation. Long-term margin evolution reflects changes in morphology from a Late Cretaceous–Eocene ramp to Oligocene and younger prograding clinothem geometries, a transition found on several other margins. Deltaic systems influenced Cretaceous and Miocene sedimentation, but, in general, the Maastrichtian–Palaeogene shelf was starved of sediment. Pre-Pleistocene sequences follow a repetitive model, with fining- and coarsening-upward successions associated with transgressions and regressions, respectively. Pleistocene–Holocene sequences are generally quite thin (&lt;20 m per sequence) and discontinuous beneath the modern shelf, reflecting starved sedimentation under high rates of eustatic change and low rates of subsidence. However, Pleistocene sequences can attain great thickness (hundreds of metres) beneath the outermost shelf and continental slope. Holocene sedimentation on the inner shelf reflects transgression, decelerating from rates of approximately 3–4 to around 2 mm a<sup>−1</sup> from 5 to 2 ka. Modern shelf sedimentation primarily reflects palimpsest sand sheets plastered and reworked into geostrophically controlled nearshore and shelf shore-oblique sand ridges, and does not provide a good analogue for pre-Pleistocene deposition.
DOI: 10.6084/m9.figshare.3453722
title: High-precision U–Pb zircon CA-ID-TIMS dates from western European late Viséan bentonites

description: Three new U–Pb zircon chemical abrasion isotope dilution thermal ionization mass spectrometry dates obtained from late Viséan Belgian bentonites are reported and are used to estimate the periodicity of early Warnantian shallowing-upwards carbonate parasequences that are interbedded with the dated bentonites. Early Warnantian parasequences exhibit mean cycle periodicity values that are consistent with the <em>c</em>. 100 ka Milankovitch cycle, which is the dominant Milankovitch frequency recognized from recent Pleistocene glacial records, and thus strengthen the arguments for (1) these sedimentary cycles being of glacio-eustatic origin and (2) the initiation of the main phase of late Palaeozoic glaciation before the start of or during earliest Warnantian times. The new dates also provide additional high-precision age constraints for the improved calibration of the Mississippian time scale. Using the new dates, the stratigraphical age of the Clyde Plateau Volcanic Formation, Midland Valley of Scotland, is revised from Holkerian to early Asbian.
DOI: 10.6084/m9.figshare.3453722.v1
title: High-precision U–Pb zircon CA-ID-TIMS dates from western European late Viséan bentonites

description: Three new U–Pb zircon chemical abrasion isotope dilution thermal ionization mass spectrometry dates obtained from late Viséan Belgian bentonites are reported and are used to estimate the periodicity of early Warnantian shallowing-upwards carbonate parasequences that are interbedded with the dated bentonites. Early Warnantian parasequences exhibit mean cycle periodicity values that are consistent with the <em>c</em>. 100 ka Milankovitch cycle, which is the dominant Milankovitch frequency recognized from recent Pleistocene glacial records, and thus strengthen the arguments for (1) these sedimentary cycles being of glacio-eustatic origin and (2) the initiation of the main phase of late Palaeozoic glaciation before the start of or during earliest Warnantian times. The new dates also provide additional high-precision age constraints for the improved calibration of the Mississippian time scale. Using the new dates, the stratigraphical age of the Clyde Plateau Volcanic Formation, Midland Valley of Scotland, is revised from Holkerian to early Asbian.