cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3454292
title: Exhumation and metamorphism of an ultrahigh-grade terrane: geochronometric investigations of the Sudete Mountains (Bohemia), Poland and Czech Republic

description: The Sudete Mountains, NE Bohemian Massif (Czech Republic and Poland), preserve abundant eclogitic and granulitic centimetre- to decimetre-scale boudins enveloped in a predominantly migmatitic matrix. Published geochronometry and thermobarometry from the UHP and UHT rocks broadly constrain the crystallization and initial stage 1 exhumation history for these units; however, the timing of stage 2 metamorphism and associated unroofing is less well constrained. New <em>in situ</em> ion microprobe Th–Pb monazite results, together with complementary U–Pb zircon and electron microprobe analyser total-Pb monazite results, on 11 amphibolite-facies gneissic to migmatitic samples, place important temporal constraints on the second stage of UHP and UHT metamorphism–exhumation. The Orlica–Snieznik Dome records UHP metamorphism occurring at 375 Ma and subsequent exhumation to midcrustal levels in supra-Barrovian conditions at <em>c</em>. 345–330 Ma. In contrast, the western Góry Sowie Block preserves evidence of HP-granulite conditions at <em>c</em>. 400 Ma, and exhumation to mid-crustal levels at 380–370 Ma, revealing a <em>c</em>. 30 million years difference in exhumation events between the neighbouring terranes. The eastern Góry Sowie Block preserves ages similar to the Orlica–Sneiznik Dome, suggesting that different preserved metamorphic–cooling histories are juxtaposed across the Sudetic Marginal fault. The bounding Niemcza shear zone yields preliminary Th–Pb dates that range from 380 ± 8 Ma to 283 ± 2 Ma, preserving a protracted metamorphic record that spans the exhumation history of the region. The distinct collapsed geochronologies of both terranes probably reflect rapid vertical transport of low-viscosity crust under supra-Barrovian conditions near the mid-crustal high-strength lid during oblique (transpressional) convergence.
DOI: 10.6084/m9.figshare.3454292.v1
title: Exhumation and metamorphism of an ultrahigh-grade terrane: geochronometric investigations of the Sudete Mountains (Bohemia), Poland and Czech Republic

description: The Sudete Mountains, NE Bohemian Massif (Czech Republic and Poland), preserve abundant eclogitic and granulitic centimetre- to decimetre-scale boudins enveloped in a predominantly migmatitic matrix. Published geochronometry and thermobarometry from the UHP and UHT rocks broadly constrain the crystallization and initial stage 1 exhumation history for these units; however, the timing of stage 2 metamorphism and associated unroofing is less well constrained. New <em>in situ</em> ion microprobe Th–Pb monazite results, together with complementary U–Pb zircon and electron microprobe analyser total-Pb monazite results, on 11 amphibolite-facies gneissic to migmatitic samples, place important temporal constraints on the second stage of UHP and UHT metamorphism–exhumation. The Orlica–Snieznik Dome records UHP metamorphism occurring at 375 Ma and subsequent exhumation to midcrustal levels in supra-Barrovian conditions at <em>c</em>. 345–330 Ma. In contrast, the western Góry Sowie Block preserves evidence of HP-granulite conditions at <em>c</em>. 400 Ma, and exhumation to mid-crustal levels at 380–370 Ma, revealing a <em>c</em>. 30 million years difference in exhumation events between the neighbouring terranes. The eastern Góry Sowie Block preserves ages similar to the Orlica–Sneiznik Dome, suggesting that different preserved metamorphic–cooling histories are juxtaposed across the Sudetic Marginal fault. The bounding Niemcza shear zone yields preliminary Th–Pb dates that range from 380 ± 8 Ma to 283 ± 2 Ma, preserving a protracted metamorphic record that spans the exhumation history of the region. The distinct collapsed geochronologies of both terranes probably reflect rapid vertical transport of low-viscosity crust under supra-Barrovian conditions near the mid-crustal high-strength lid during oblique (transpressional) convergence.
DOI: 10.6084/m9.figshare.3454289
title: Geochronology of Proterozoic basement inliers in the Colombian Andes: tectonic history of remnants of a fragmented Grenville belt

description: Basement inliers of high-grade metamorphic rocks within the eastern Colombian Andes record a Grenvillian history. Among them, the Garzón Complex and the Dibulla, Bucaramanga and Jojoncito gneisses were studied using different geochronological methods to produce better correlations in the context of the reconstruction of the Grenville belt and of the supercontinent of Rodinia. The dynamic evolution of all of these units includes a final collisional event with exhumation of high-grade rocks. Such a tectonic history bears strong similarities with the Grenville Province in Canada and seems to confirm that these domains took part in the aggregation of Rodinia. Mesoproterozoic U-Pb zircon ages indicate heritage from magmatic protoliths, and the Sm-Nd model ages, as well as the ε<sub>Nd</sub> values, suggest derivation from an evolved continental domain, such as the Amazonian craton, with some mixing with juvenile Neoproterozoic material. When these continental fragments are correlated with similar terrains in Mexico and the Central Andes, a large crustal fragment is implied; very probably it made up the southern portion of the Grenville belt within Rodinia, which was disrupted when Laurentia separated from Gondwana forming the Iapetus Ocean, leaving behind cratonic fragments that were later accreted to the South American Platform.
DOI: 10.6084/m9.figshare.3454289.v1
title: Geochronology of Proterozoic basement inliers in the Colombian Andes: tectonic history of remnants of a fragmented Grenville belt

description: Basement inliers of high-grade metamorphic rocks within the eastern Colombian Andes record a Grenvillian history. Among them, the Garzón Complex and the Dibulla, Bucaramanga and Jojoncito gneisses were studied using different geochronological methods to produce better correlations in the context of the reconstruction of the Grenville belt and of the supercontinent of Rodinia. The dynamic evolution of all of these units includes a final collisional event with exhumation of high-grade rocks. Such a tectonic history bears strong similarities with the Grenville Province in Canada and seems to confirm that these domains took part in the aggregation of Rodinia. Mesoproterozoic U-Pb zircon ages indicate heritage from magmatic protoliths, and the Sm-Nd model ages, as well as the ε<sub>Nd</sub> values, suggest derivation from an evolved continental domain, such as the Amazonian craton, with some mixing with juvenile Neoproterozoic material. When these continental fragments are correlated with similar terrains in Mexico and the Central Andes, a large crustal fragment is implied; very probably it made up the southern portion of the Grenville belt within Rodinia, which was disrupted when Laurentia separated from Gondwana forming the Iapetus Ocean, leaving behind cratonic fragments that were later accreted to the South American Platform.
DOI: 10.6084/m9.figshare.3454286
title: Nd and Sr isotopic signatures of metasedimentary rocks around the South Pacific margin and implications for their provenance

description: An Nd-Sr isotope database, including <em>c.</em> 200 new analyses, is presented for Palaeozoic and Mesozoic metasedimentary successions extending through southeastern Australia, New Zealand, West Antarctica and the Antarctic Peninsula to southern South America. Combining with U-Pb detrital zircon age data, this enables characterization of New Zealand terranes, especially within the Eastern Province, where there is a progression from westernmost terranes of both volcanic/volcaniclastic and accretionary origin with primitive sediment sources, to easternmost terranes with mature continental sediment inputs. In southern South America, West Antarctica and the Antarctica Peninsula, similar accretionary complexes have Nd model ages principally reflecting mixing of sedimentary material from multiple sources, both mature and juvenile. A mature Gondwana continental provenance dominates in sedimentary basins inboard of the active margin, especially in the Palaeozoic (Western Province, New Zealand, interior West Antarctica and NW Argentina), and contributes significantly to pre-Mesozoic sedimentary rocks of Patagonia east of the Andes. Along the Gondwanaland margin, Nd systematics for younger (late Palaeozoic to early Mesozoic) accretionary complex metasediments reflect younger source inputs, notably in the Scotia metamorphic complex. Many of the accretionary complex deposits must involve significant crustal reworking. There is no apparent South American equivalent of the primitive provenance of the westernmost accretionary terranes of New Zealand.
DOI: 10.6084/m9.figshare.3454286.v1
title: Nd and Sr isotopic signatures of metasedimentary rocks around the South Pacific margin and implications for their provenance

description: An Nd-Sr isotope database, including <em>c.</em> 200 new analyses, is presented for Palaeozoic and Mesozoic metasedimentary successions extending through southeastern Australia, New Zealand, West Antarctica and the Antarctic Peninsula to southern South America. Combining with U-Pb detrital zircon age data, this enables characterization of New Zealand terranes, especially within the Eastern Province, where there is a progression from westernmost terranes of both volcanic/volcaniclastic and accretionary origin with primitive sediment sources, to easternmost terranes with mature continental sediment inputs. In southern South America, West Antarctica and the Antarctica Peninsula, similar accretionary complexes have Nd model ages principally reflecting mixing of sedimentary material from multiple sources, both mature and juvenile. A mature Gondwana continental provenance dominates in sedimentary basins inboard of the active margin, especially in the Palaeozoic (Western Province, New Zealand, interior West Antarctica and NW Argentina), and contributes significantly to pre-Mesozoic sedimentary rocks of Patagonia east of the Andes. Along the Gondwanaland margin, Nd systematics for younger (late Palaeozoic to early Mesozoic) accretionary complex metasediments reflect younger source inputs, notably in the Scotia metamorphic complex. Many of the accretionary complex deposits must involve significant crustal reworking. There is no apparent South American equivalent of the primitive provenance of the westernmost accretionary terranes of New Zealand.
DOI: 10.6084/m9.figshare.3454280
title: Cambrian reworking of the southern Australian Proterozoic Curnamona Province: constraints from regional shear-zone systems

description: Palaeoproterozoic to early Mesoproterozoic metamorphic rocks of the Curnamona Province, southern Australia, are crosscut by a system of regional-scale shear zones that locally dominate the terrain. Combined metamorphic and geochronological data from localities across the southern Curnamona Province indicate that the peak metamorphic shear-zone assemblages formed during the Cambrian (<em>c</em>. 500 Ma) Delamerian Orogeny, and not during the waning stages of the <em>c</em>. 1600 Ma Olarian Orogeny as has been previously asserted. A combination of monazite chemical U–Th–Pb and garnet Sm–Nd geochronology indicates that shear-zone fabrics formed between 497 and 517 Ma. Peak metamorphic conditions obtained from prograde garnet–staurolite–biotite–muscovite–chlorite–quartz assemblages are between 530 and 600 °C at pressures of around 5 kbar. The apparent absence of significant up-pressure prograde paths recorded by the mineral assemblages, together with modest (10–20%) Delamerian shortening, suggests that attainment of burial to depths of around 18 km was largely a function of pre-Delamerian sedimentation over the interval from <em>c</em>. 700 to 530 Ma. The spatial association between the pattern of basement metamorphism and reactivation during the Delamerian Orogeny is interpreted to reflect in part the distribution of pre-Delamerian sedimentation, and highlights the potential importance of pre-orogenic processes such as basin development in controlling the style and pattern of later terrain reactivation and reworking.
DOI: 10.6084/m9.figshare.3454280.v1
title: Cambrian reworking of the southern Australian Proterozoic Curnamona Province: constraints from regional shear-zone systems

description: Palaeoproterozoic to early Mesoproterozoic metamorphic rocks of the Curnamona Province, southern Australia, are crosscut by a system of regional-scale shear zones that locally dominate the terrain. Combined metamorphic and geochronological data from localities across the southern Curnamona Province indicate that the peak metamorphic shear-zone assemblages formed during the Cambrian (<em>c</em>. 500 Ma) Delamerian Orogeny, and not during the waning stages of the <em>c</em>. 1600 Ma Olarian Orogeny as has been previously asserted. A combination of monazite chemical U–Th–Pb and garnet Sm–Nd geochronology indicates that shear-zone fabrics formed between 497 and 517 Ma. Peak metamorphic conditions obtained from prograde garnet–staurolite–biotite–muscovite–chlorite–quartz assemblages are between 530 and 600 °C at pressures of around 5 kbar. The apparent absence of significant up-pressure prograde paths recorded by the mineral assemblages, together with modest (10–20%) Delamerian shortening, suggests that attainment of burial to depths of around 18 km was largely a function of pre-Delamerian sedimentation over the interval from <em>c</em>. 700 to 530 Ma. The spatial association between the pattern of basement metamorphism and reactivation during the Delamerian Orogeny is interpreted to reflect in part the distribution of pre-Delamerian sedimentation, and highlights the potential importance of pre-orogenic processes such as basin development in controlling the style and pattern of later terrain reactivation and reworking.
DOI: 10.6084/m9.figshare.3454277
title: Volumetric matrix strain related to intraformational faulting in argillaceous sediments

description: Soft-sediment deformation involves complex interactions between discrete fracturing and diffuse bulk strain, described in terms of volume change and shear strain in a critical state mechanics framework. This study reports on a mesoscale normal fault zone, intraformational in Oligocene argillaceous sediments from the Boom Formation (Belgium), containing several metre-scale normal fault strands. They form either discrete fault planes or decimetre-wide shear zones with internal fabric. The faults have been subjected to microtectonic and petrophysical analysis. Small but significant changes occur in the porous network of the argillaceous matrix approaching a fault or shear zone, indicating compactional strain in both footwall and hanging wall. Internal compaction associated with faulting is put forward as a ductile–brittle feedback mechanism in the kinematics of intraformational fracture systems. Small differential stress induced by compaction and minor regional tectonic forces (differential uplift and tilt) and subsequent gravitational forces (downslope shear stress) induce small shear bands in nearly critically stressed weak mud. Shear banding is accompanied by layer-parallel shortening and bulk volume loss. This provides an additional extension of endogenous origin, accommodated by further deformation. This ductile–brittle feedback mechanism eventually leads to commonly observed intraformational collapse structures called polygonal fault systems.
DOI: 10.6084/m9.figshare.3454277.v1
title: Volumetric matrix strain related to intraformational faulting in argillaceous sediments

description: Soft-sediment deformation involves complex interactions between discrete fracturing and diffuse bulk strain, described in terms of volume change and shear strain in a critical state mechanics framework. This study reports on a mesoscale normal fault zone, intraformational in Oligocene argillaceous sediments from the Boom Formation (Belgium), containing several metre-scale normal fault strands. They form either discrete fault planes or decimetre-wide shear zones with internal fabric. The faults have been subjected to microtectonic and petrophysical analysis. Small but significant changes occur in the porous network of the argillaceous matrix approaching a fault or shear zone, indicating compactional strain in both footwall and hanging wall. Internal compaction associated with faulting is put forward as a ductile–brittle feedback mechanism in the kinematics of intraformational fracture systems. Small differential stress induced by compaction and minor regional tectonic forces (differential uplift and tilt) and subsequent gravitational forces (downslope shear stress) induce small shear bands in nearly critically stressed weak mud. Shear banding is accompanied by layer-parallel shortening and bulk volume loss. This provides an additional extension of endogenous origin, accommodated by further deformation. This ductile–brittle feedback mechanism eventually leads to commonly observed intraformational collapse structures called polygonal fault systems.
DOI: 10.6084/m9.figshare.3454274
title: Detrital zircon provenance constraints on the evolution of the Harts Range Metamorphic Complex (central Australia): links to the Centralian Superbasin

description: Until recently it has been widely accepted that protoliths to metasediments of the Harts Range Metamorphic Complex (central Australia) were deposited prior to <em>c</em>. 1.75 Ga and form part of the Palaeoproterozoic Arunta Inlier. However, new sensitive high-resolution ion microprobe U–Pb analyses of detrital zircon, together with recently published data, suggest that they were deposited coeval with <em>c</em>. 545–520 Ma sediments from the adjacent, little metamorphosed Neoproterozoic to Palaeozoic Centralian Superbasin. Protoliths of the Harts Range Metamorphic Complex were deposited in the Irindina sub-basin, an early- to mid-Cambrian rift located between the present-day Amadeus and Georgina Basin remnants of the Centralian Superbasin. Deposition occurred during a widespread and long-lived interval of extension in parts of central Australia associated with eruption of the voluminous Kalkarinji Continental Flood Basalts. The Harts Range Metamorphic Complex was metamorphosed to upper amphibolite- to granulite-facies conditions within <em>c</em>. 40 Ma of deposition of its sedimentary protoliths.
DOI: 10.6084/m9.figshare.3454274.v1
title: Detrital zircon provenance constraints on the evolution of the Harts Range Metamorphic Complex (central Australia): links to the Centralian Superbasin

description: Until recently it has been widely accepted that protoliths to metasediments of the Harts Range Metamorphic Complex (central Australia) were deposited prior to <em>c</em>. 1.75 Ga and form part of the Palaeoproterozoic Arunta Inlier. However, new sensitive high-resolution ion microprobe U–Pb analyses of detrital zircon, together with recently published data, suggest that they were deposited coeval with <em>c</em>. 545–520 Ma sediments from the adjacent, little metamorphosed Neoproterozoic to Palaeozoic Centralian Superbasin. Protoliths of the Harts Range Metamorphic Complex were deposited in the Irindina sub-basin, an early- to mid-Cambrian rift located between the present-day Amadeus and Georgina Basin remnants of the Centralian Superbasin. Deposition occurred during a widespread and long-lived interval of extension in parts of central Australia associated with eruption of the voluminous Kalkarinji Continental Flood Basalts. The Harts Range Metamorphic Complex was metamorphosed to upper amphibolite- to granulite-facies conditions within <em>c</em>. 40 Ma of deposition of its sedimentary protoliths.
DOI: 10.6084/m9.figshare.3454271
title: Degree of magnetic anisotropy as a strain intensity gauge in ferromagnetic granites

description: Anisotropy of magnetic susceptibility data for a ferromagnetic granite (Godhra Granite, NW India) are presented and it is shown that the degree of magnetic anisotropy (<strong><em>P</em></strong>′) is not controlled by the mean susceptibility (<strong><em>K</em></strong><sub>m</sub>). Analyses carried out across a high-strain zone lying between granite and adjacent gneiss show that <strong><em>P</em></strong>′ values are highest in samples that lie close to the contact and decrease away from it. Based on these results it is concluded that if <strong><em>P</em></strong>′ is not controlled by <strong><em>K</em></strong><sub>m</sub>, then the former can be used to gauge strain-intensity variations in ferromagnetic granites.
DOI: 10.6084/m9.figshare.3454271.v1
title: Degree of magnetic anisotropy as a strain intensity gauge in ferromagnetic granites

description: Anisotropy of magnetic susceptibility data for a ferromagnetic granite (Godhra Granite, NW India) are presented and it is shown that the degree of magnetic anisotropy (<strong><em>P</em></strong>′) is not controlled by the mean susceptibility (<strong><em>K</em></strong><sub>m</sub>). Analyses carried out across a high-strain zone lying between granite and adjacent gneiss show that <strong><em>P</em></strong>′ values are highest in samples that lie close to the contact and decrease away from it. Based on these results it is concluded that if <strong><em>P</em></strong>′ is not controlled by <strong><em>K</em></strong><sub>m</sub>, then the former can be used to gauge strain-intensity variations in ferromagnetic granites.
DOI: 10.6084/m9.figshare.3454268
title: The extensional Messaria shear zone and associated brittle detachment faults, Aegean Sea, Greece

description: Structural, thermochronological and metamorphic data are used to elucidate the tectonic nature and evolution of the ductile extensional Messaria shear zone and the associated brittle Messaria and Fanari detachment faults, which exhumed their footwall from mid-crustal depths on the island of Ikaria in the Aegean. Thermobarometric data indicate that the Messaria shear zone formed at 350–&gt;400 °C and 3–4 kbar (i.e. at a depth of <em>c</em>. 15 km). Normal faulting was accompanied by the intrusion of two granites, which together with the thermobarometric data indicate a relatively high thermal field gradient of 25–35 °C km<sup>−1</sup>. Zircon and apatite fission-track and apatite (U–Th)/He ages demonstrate rapid cooling in the footwall of the Messaria detachment from <em>c</em>. 400 °C to <em>c</em>. 40 °C between 11 and 3 Ma. Age–distance relationships of the data suggest that the Messaria shear zone and the Messaria detachment slipped at apparent rates of <em>c</em>. 6–9 km Ma<sup>−1</sup>. Kinematic indicators show a consistent top-to-the-NNE shear sense for the extensional faults. However, at the southern part of the Messaria detachment some late-stage shear-sense indicators are top-to-the-SSW and are assumed to be associated with updoming of the footwall. Numerous deformed pegmatite veins in the Messaria shear zone allow the reconstruction of deformation and flow parameters. The mean kinematic vorticity number ranges from 0.13 to 0.80, indicating that shearing deviated significantly from simple shear; that is, extensional shearing was associated with vertical ductile thinning, which contributed to tectonic exhumation. Finite strain shows oblate geometries and axial ratios of the finite-strain ellipse in sections parallel to tectonic transport and normal to the mylonitic foliation range from 1.8 to 19.9. We calculate, using a 1D numerical model, that vertical ductile thinning contributed <em>c</em>. 20% to exhumation during extensional shearing. Normal faulting was the major agent exhuming the footwall from <em>c</em>. 15 km depth.