cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3453719
title: Physical modelling of large-scale deformational systems in the South Polar Layered Deposits (Promethei Lingula, Mars): new geological constraints and climatic implications

description: Deformation systems (DSs) locally affect the South Polar Layered Deposits (SPLDs) along the margins of the Promethei Lingula ice sheet (part of the southern Martian ice-dome). One example is the ‘S<sub>2</sub>’ deformation system, characterized by a complex pattern of brittle and brittle–ductile structures related to kilometre-scale shear zones that deform the sequence. Moreover, soft-sediment structures affect one layer located at the base of the S<sub>2</sub>. An earlier structural analysis suggested that: (1) two deformation stages (D<sub>1</sub>, in which the shear zones developed, and D<sub>2</sub>, in which the D<sub>1</sub> structures were reactivated by deep-seated gravitational slope deformation) occurred, driven by gravity; and (2) there are variations in the bulk composition of the SPLD (which is inferred to be mainly composed of water ice plus basaltic dust). This work supports these structural results through thermal and mechanical modelling of the S<sub>2</sub> sequence. Our modelling results suggest that several layers within the S<sub>2</sub> system are probably composed of, or are mixed with, CO<sub>2</sub> ice, and that the development of the observed deformation is inconsistent with present-day physical conditions. Soft-sediment structures probably formed under warmer surface temperatures during the past, with those warmer temperatures favouring or even triggering ice flow/basal sliding of the Promethei Lingula.
DOI: 10.6084/m9.figshare.3453719.v1
title: Physical modelling of large-scale deformational systems in the South Polar Layered Deposits (Promethei Lingula, Mars): new geological constraints and climatic implications

description: Deformation systems (DSs) locally affect the South Polar Layered Deposits (SPLDs) along the margins of the Promethei Lingula ice sheet (part of the southern Martian ice-dome). One example is the ‘S<sub>2</sub>’ deformation system, characterized by a complex pattern of brittle and brittle–ductile structures related to kilometre-scale shear zones that deform the sequence. Moreover, soft-sediment structures affect one layer located at the base of the S<sub>2</sub>. An earlier structural analysis suggested that: (1) two deformation stages (D<sub>1</sub>, in which the shear zones developed, and D<sub>2</sub>, in which the D<sub>1</sub> structures were reactivated by deep-seated gravitational slope deformation) occurred, driven by gravity; and (2) there are variations in the bulk composition of the SPLD (which is inferred to be mainly composed of water ice plus basaltic dust). This work supports these structural results through thermal and mechanical modelling of the S<sub>2</sub> sequence. Our modelling results suggest that several layers within the S<sub>2</sub> system are probably composed of, or are mixed with, CO<sub>2</sub> ice, and that the development of the observed deformation is inconsistent with present-day physical conditions. Soft-sediment structures probably formed under warmer surface temperatures during the past, with those warmer temperatures favouring or even triggering ice flow/basal sliding of the Promethei Lingula.
DOI: 10.6084/m9.figshare.3453716
title: Scale invariance in fluvial barforms: implications for interpretation of fluvial systems in the rock record

description: Understanding the controls on the size and shape of sandstone bodies deposited by fluvial systems is important in the reconstruction of ancient fluvial deposits and construction of quantitative reservoir models. Measurements and analyses of sandbodies from remotely sensed imagery have allowed quantification of width and length ratios of barforms in modern fluvial systems. For bank-attached bars the width:length ratios range between 0.12 and 0.47 (arithmetic mean: 0.25), for lateral bars between 0.19 and 0.42 (arithmetic mean: 0.30), for mid-channel bars between 0.09 and 0.49 (arithmetic mean: 0.28), and for point bars between 0.14 and 0.50 (arithmetic mean: 0.30). The majority of width:length ratios for all bar types range between 0.15 and 0.35. Examination of other parameters such as basin type, planform geometry, apparent stream width, river length, gradient over the investigated area, aggradational or degradational system, tectonic setting and climate do not significantly affect the width:length ratio. Therefore, the bar planform shape, the width:length ratio, can be considered to be scale invariant. The recognition that bar planform shape in fluvial systems is scale invariant will be useful in the construction of subsurface three-dimensional models of fluvial deposits with variable dimensions.
DOI: 10.6084/m9.figshare.3453716.v1
title: Scale invariance in fluvial barforms: implications for interpretation of fluvial systems in the rock record

description: Understanding the controls on the size and shape of sandstone bodies deposited by fluvial systems is important in the reconstruction of ancient fluvial deposits and construction of quantitative reservoir models. Measurements and analyses of sandbodies from remotely sensed imagery have allowed quantification of width and length ratios of barforms in modern fluvial systems. For bank-attached bars the width:length ratios range between 0.12 and 0.47 (arithmetic mean: 0.25), for lateral bars between 0.19 and 0.42 (arithmetic mean: 0.30), for mid-channel bars between 0.09 and 0.49 (arithmetic mean: 0.28), and for point bars between 0.14 and 0.50 (arithmetic mean: 0.30). The majority of width:length ratios for all bar types range between 0.15 and 0.35. Examination of other parameters such as basin type, planform geometry, apparent stream width, river length, gradient over the investigated area, aggradational or degradational system, tectonic setting and climate do not significantly affect the width:length ratio. Therefore, the bar planform shape, the width:length ratio, can be considered to be scale invariant. The recognition that bar planform shape in fluvial systems is scale invariant will be useful in the construction of subsurface three-dimensional models of fluvial deposits with variable dimensions.
DOI: 10.6084/m9.figshare.3453713
title: Leaf habit of Late Permian <em>Glossopteris</em> trees from high-palaeolatitude forests

description: The leaf longevity of trees, deciduous or evergreen, plays an important role in climate feedbacks and plant ecology. In modern forests of the high latitudes, evergreen trees dominate; however, the fossil record indicates that deciduous vegetation dominated during some previous warm intervals. We show, through an integration of palaeobotanical techniques and isotope geochemistry of trees in one of the earliest polar forests (Late Permian, <em>c</em>. 260 Ma, Antarctica), that the arborescent glossopterid taxa were both deciduous and evergreen, with a greater abundance of evergreen trees occurring in the studied forests. These new findings suggest the possibility that deciduousness was a plastic trait in ancient polar plants, and that deciduous plants, migrating poleward from lower latitudes, were probably better adapted to high-disturbance areas in environments that were light-limited.
DOI: 10.6084/m9.figshare.3453713.v1
title: Leaf habit of Late Permian <em>Glossopteris</em> trees from high-palaeolatitude forests

description: The leaf longevity of trees, deciduous or evergreen, plays an important role in climate feedbacks and plant ecology. In modern forests of the high latitudes, evergreen trees dominate; however, the fossil record indicates that deciduous vegetation dominated during some previous warm intervals. We show, through an integration of palaeobotanical techniques and isotope geochemistry of trees in one of the earliest polar forests (Late Permian, <em>c</em>. 260 Ma, Antarctica), that the arborescent glossopterid taxa were both deciduous and evergreen, with a greater abundance of evergreen trees occurring in the studied forests. These new findings suggest the possibility that deciduousness was a plastic trait in ancient polar plants, and that deciduous plants, migrating poleward from lower latitudes, were probably better adapted to high-disturbance areas in environments that were light-limited.
DOI: 10.6084/m9.figshare.3453707
title: Early Permian 90° clockwise rotation of the Maures–Estérel–Corsica–Sardinia block confirmed by new palaeomagnetic data and followed by a Triassic 60° clockwise rotation

description: Palaeomagnetic investigations of the Corso-Sardinian block and Maures–Estérel show that there has been a change in their magnetic orientation during the Late Carboniferous–Early Permian period (305–280 Ma). This trend is interpreted in terms of a large-scale 90° clockwise rotation of the southern branch of the Variscan belt that matches the successive change in shortening directions revealed by structural geology. The evidence is based on existing structural studies of the fabrics of syntectonically emplaced granitoids partly based on the anisotropy of magnetic susceptibility, combined with a large database of isotopic ages. The chronological match between the palaeomagnetic and tectonic datasets is interpreted here as a result of large-scale dextral wrench movements in the lithosphere between the Gondwana and Laurussia supercontinents. This wrench deformation is regarded as a sequel to the dextral rotation of the northern branch of the Variscan belt during 330–315 Ma which terminated in frontal collision with Avalonia. The continuation of movement in the southern Variscan realm was due to shearing along the southern margin of the Avalonian block. An additional clockwise rotation is inferred to have taken place during the Triassic period. The age of this motion remains to be determined.
DOI: 10.6084/m9.figshare.3453707.v1
title: Early Permian 90° clockwise rotation of the Maures–Estérel–Corsica–Sardinia block confirmed by new palaeomagnetic data and followed by a Triassic 60° clockwise rotation

description: Palaeomagnetic investigations of the Corso-Sardinian block and Maures–Estérel show that there has been a change in their magnetic orientation during the Late Carboniferous–Early Permian period (305–280 Ma). This trend is interpreted in terms of a large-scale 90° clockwise rotation of the southern branch of the Variscan belt that matches the successive change in shortening directions revealed by structural geology. The evidence is based on existing structural studies of the fabrics of syntectonically emplaced granitoids partly based on the anisotropy of magnetic susceptibility, combined with a large database of isotopic ages. The chronological match between the palaeomagnetic and tectonic datasets is interpreted here as a result of large-scale dextral wrench movements in the lithosphere between the Gondwana and Laurussia supercontinents. This wrench deformation is regarded as a sequel to the dextral rotation of the northern branch of the Variscan belt during 330–315 Ma which terminated in frontal collision with Avalonia. The continuation of movement in the southern Variscan realm was due to shearing along the southern margin of the Avalonian block. An additional clockwise rotation is inferred to have taken place during the Triassic period. The age of this motion remains to be determined.
DOI: 10.6084/m9.figshare.3453704
title: A downscaling approach for geological characterization of the Raditladi basin of Mercury

description: In this work, we combined multi-scale geological maps of Mercury to produce a new global map where geological units are classified based on albedo, crater density and morphological relationships with other units. To create this map, we used the 250 m/pixel mosaic of images acquired by the narrow- and wide-angle cameras onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft during its orbital phase. The geological mapping is supported by digital terrain model data and surface mineralogical variation from the global mosaic of MESSENGER Mercury Atmospheric and Surface Composition Spectrometer observations. This map comprises the global-scale intercrater plains, smooth plains and Odin-type units as reported in previous studies, as well as units we term bright intercrater plains, Caloris rough ejecta and dark material deposits. We mapped a portion of the Raditladi quadrangle (19–35°N, 106–133°E) at a regional scale at a resolution of 166 m/pixel. We characterized the geological context of the area and evaluated the stratigraphic relationships between the units. To obtain a representative geological section, we analysed and corrected available topographical data. The geological cross-section derived from our regional mapping suggests that volcanic emplacement of Raditladi's inner plains followed the topography of the basin after the deposition of impact-related units (i.e. melts, breccias and rim collapse) and was driven by low-viscosity flows. Hollows that appear on Raditladi's peak ring were possibly formed from low-reflectance intercrater plains materials exposed through the peak ring unit.
DOI: 10.6084/m9.figshare.3453704.v1
title: A downscaling approach for geological characterization of the Raditladi basin of Mercury

description: In this work, we combined multi-scale geological maps of Mercury to produce a new global map where geological units are classified based on albedo, crater density and morphological relationships with other units. To create this map, we used the 250 m/pixel mosaic of images acquired by the narrow- and wide-angle cameras onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft during its orbital phase. The geological mapping is supported by digital terrain model data and surface mineralogical variation from the global mosaic of MESSENGER Mercury Atmospheric and Surface Composition Spectrometer observations. This map comprises the global-scale intercrater plains, smooth plains and Odin-type units as reported in previous studies, as well as units we term bright intercrater plains, Caloris rough ejecta and dark material deposits. We mapped a portion of the Raditladi quadrangle (19–35°N, 106–133°E) at a regional scale at a resolution of 166 m/pixel. We characterized the geological context of the area and evaluated the stratigraphic relationships between the units. To obtain a representative geological section, we analysed and corrected available topographical data. The geological cross-section derived from our regional mapping suggests that volcanic emplacement of Raditladi's inner plains followed the topography of the basin after the deposition of impact-related units (i.e. melts, breccias and rim collapse) and was driven by low-viscosity flows. Hollows that appear on Raditladi's peak ring were possibly formed from low-reflectance intercrater plains materials exposed through the peak ring unit.
DOI: 10.6084/m9.figshare.3453701
title: Devonian–Permian magmatic pulses in the northern Vosges Mountains (NE France): result of continuous subduction of the Rhenohercynian Ocean and Avalonian passive margin

description: Middle Devonian–Permian magmatic rocks from the northern Vosges Mountains show temporal and chemical variations which are linked to the continuous subduction of the Rhenohercynian oceanic crust and the Avalonian Devonian passive margin underneath the Saxothuringian continental crust. Major and trace elements and Sr–Nd isotopes of the northern Vosges basic to acidic magmatic rocks show that they evolved through time from: (1) Middle Devonian tholeiitic to calc-alkaline volcanic Rabodeau–Schirmeck sequence derived from partial melting of a depleted mantle, with these primary magmas having triggered anatexis of young crustal material of the Saxothuringian crust; (2) calc-alkaline Bande Médiane volcanic belt (<em>c.</em> 334 Ma), diorite and Hohwald granodiorite intrusion (<em>c.</em> 329 Ma) originated from enriched mantle contaminated and metasomatized by fluids expelled from a subduction zone; (3) high-K calc-alkaline Belmont granite (<em>c.</em> 318 Ma), whose chemical signature suggests magma-mixing between enriched mantle-derived melts and magmas from a young crustal source; (4) Mg–K Younger granite (<em>c.</em> 312 Ma) might be related to partial melting of enriched mantle which interacted with juvenile crustal material; and (5) Kagenfels S-type granite and Permian volcanic rocks generated by anatexis of meta-igneous and minor metasedimentary rocks.
DOI: 10.6084/m9.figshare.3453701.v1
title: Devonian–Permian magmatic pulses in the northern Vosges Mountains (NE France): result of continuous subduction of the Rhenohercynian Ocean and Avalonian passive margin

description: Middle Devonian–Permian magmatic rocks from the northern Vosges Mountains show temporal and chemical variations which are linked to the continuous subduction of the Rhenohercynian oceanic crust and the Avalonian Devonian passive margin underneath the Saxothuringian continental crust. Major and trace elements and Sr–Nd isotopes of the northern Vosges basic to acidic magmatic rocks show that they evolved through time from: (1) Middle Devonian tholeiitic to calc-alkaline volcanic Rabodeau–Schirmeck sequence derived from partial melting of a depleted mantle, with these primary magmas having triggered anatexis of young crustal material of the Saxothuringian crust; (2) calc-alkaline Bande Médiane volcanic belt (<em>c.</em> 334 Ma), diorite and Hohwald granodiorite intrusion (<em>c.</em> 329 Ma) originated from enriched mantle contaminated and metasomatized by fluids expelled from a subduction zone; (3) high-K calc-alkaline Belmont granite (<em>c.</em> 318 Ma), whose chemical signature suggests magma-mixing between enriched mantle-derived melts and magmas from a young crustal source; (4) Mg–K Younger granite (<em>c.</em> 312 Ma) might be related to partial melting of enriched mantle which interacted with juvenile crustal material; and (5) Kagenfels S-type granite and Permian volcanic rocks generated by anatexis of meta-igneous and minor metasedimentary rocks.
DOI: 10.6084/m9.figshare.3453695
title: Eocene to Miocene igneous activity in NE Greenland: northward younging of magmatism along the East Greenland margin

description: Radiometric dating by the <sup>40</sup>Ar–<sup>39</sup>Ar incremental heating method was carried out on lavas, sills, dykes, and a central intrusion from NE Greenland. Eighteen samples gave acceptable crystallization ages. Lavas of both Lower and Upper Plateau Lava Series gave ages in the range 55.5–53.5 Ma and cannot be constrained to better than 56–53 Ma. Sills and dykes from Traill Ø to Shannon, with compositions fairly similar to those of the lavas, gave ages of 55.1–51.3 Ma, contemporaneous with and slightly younger than the lavas. Alkaline lavas on inland nunataks have ages of 53–50 Ma, and the Kap Broer Ruys intrusive centre has an age of 48.7 ± 0.5 Ma. An alkaline sill on Hvalrosø is much younger at 20.3 ± 0.1 Ma. There are no pre-breakup lavas onshore NE Greenland. We surmise that the hot mantle of the Iceland plume arrived and melted extensively beneath the northern basins only at the time of breakup around 55 Ma. Post-breakup intrusive events in NE Greenland coincided with plate-tectonic events such as reorganization, uplift and opening in the north. The Hvalrosø sill represents a local small melting event that may be related to coeval opening of the Lena Trough.
DOI: 10.6084/m9.figshare.3453695.v1
title: Eocene to Miocene igneous activity in NE Greenland: northward younging of magmatism along the East Greenland margin

description: Radiometric dating by the <sup>40</sup>Ar–<sup>39</sup>Ar incremental heating method was carried out on lavas, sills, dykes, and a central intrusion from NE Greenland. Eighteen samples gave acceptable crystallization ages. Lavas of both Lower and Upper Plateau Lava Series gave ages in the range 55.5–53.5 Ma and cannot be constrained to better than 56–53 Ma. Sills and dykes from Traill Ø to Shannon, with compositions fairly similar to those of the lavas, gave ages of 55.1–51.3 Ma, contemporaneous with and slightly younger than the lavas. Alkaline lavas on inland nunataks have ages of 53–50 Ma, and the Kap Broer Ruys intrusive centre has an age of 48.7 ± 0.5 Ma. An alkaline sill on Hvalrosø is much younger at 20.3 ± 0.1 Ma. There are no pre-breakup lavas onshore NE Greenland. We surmise that the hot mantle of the Iceland plume arrived and melted extensively beneath the northern basins only at the time of breakup around 55 Ma. Post-breakup intrusive events in NE Greenland coincided with plate-tectonic events such as reorganization, uplift and opening in the north. The Hvalrosø sill represents a local small melting event that may be related to coeval opening of the Lena Trough.
DOI: 10.6084/m9.figshare.3453692
title: The Palaeogene Bracken Bay–Straiton dyke: composition and controls on intrusion

description: The Bracken Bay–Straiton dyke, a member of the Palaeogene Mull dyke swarm, is one of the Solitary dykes of southern Scotland and northern England recognized by Geikie (1897). It shows a remarkable (unique?) change of strike direction, deviating from the regional NW–SE trend to propagate along the Southern Upland Fault for 16 km before apparently resuming its southeasterly course in the Southern Uplands. The dyke is a clinopyroxene–plagioclase–phyric quartz tholeiite, showing little petrographic variation along strike. However, geochemical data indicate that the dyke segment south of the Southern Upland Fault is not comagmatic with the main dyke; it is here distinguished as the Kello Water dyke. The reason for the dyke’s deviation at the fault is uncertain but may be related to a significant role for crustal heterogeneities, particularly Caledonian fractures which had earlier been utilized by the Late Carboniferous quartz dolerite dyke swarm.
DOI: 10.6084/m9.figshare.3453692.v1
title: The Palaeogene Bracken Bay–Straiton dyke: composition and controls on intrusion

description: The Bracken Bay–Straiton dyke, a member of the Palaeogene Mull dyke swarm, is one of the Solitary dykes of southern Scotland and northern England recognized by Geikie (1897). It shows a remarkable (unique?) change of strike direction, deviating from the regional NW–SE trend to propagate along the Southern Upland Fault for 16 km before apparently resuming its southeasterly course in the Southern Uplands. The dyke is a clinopyroxene–plagioclase–phyric quartz tholeiite, showing little petrographic variation along strike. However, geochemical data indicate that the dyke segment south of the Southern Upland Fault is not comagmatic with the main dyke; it is here distinguished as the Kello Water dyke. The reason for the dyke’s deviation at the fault is uncertain but may be related to a significant role for crustal heterogeneities, particularly Caledonian fractures which had earlier been utilized by the Late Carboniferous quartz dolerite dyke swarm.