cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3454175.v1
title: A tectonostratigraphic synthesis of the Sub-Andean basins: implications for the geotectonic segmentation of the Andean Belt

description: The tectonic, structural and depositional history of 19 Sub-Andean foreland and eight southern Caribbean basins has been synthesized and is summarized by regional geohistory charts. These charts recapitulate the subsidence regimes recognized and have been used to evaluate correlations between genetically related stratigraphic sequences. Based on spatial and temporal changes in palaeo-depositional setting, the Sub-Andean region can be subdivided longitudinally into several tectonostratigraphic domains. The differential amount of subsidence between two adjacent tectonostratigraphic provinces or sub-provinces relies on the presence of a transverse zone of structural accommodation. The location of these transfer zones correlates with a number of known and several newly identified zones of intracontinental deformation. Combined with changes in the structural geometry of the Andean Fold and Thrust Belt and the relative dominance of basement fault systems along the length of the Andean foreland, it is suggested that the Andean Belt can be separated into five tectonic domains (which are themselves bounded by transverse, structural accommodation zones). Representing the multiphase reactivation of pre-existing basement fault systems, the influence of these broad zones of transcontinental deformation is most apparent during the Triassic–Jurassic period, suggesting that they were intimately associated with accommodating intraplate stresses during the breakup of the Gondwana Supercontinent.
DOI: 10.6084/m9.figshare.3454172
title: Single-zircon geochronology and Nd isotopic systematics of Proterozoic high-grade rocks from the Mozambique belt of southern Tanzania (Masasi area): implications for Gondwana assembly

description: The Mozambique belt of southern Tanzania is underlain by locally restricted 1100–950 Ma (late Kibaran) granitoid gneisses that were derived from remelting of Archaean continental crust, as suggested by Nd isotopic systematics. These rocks were deformed and metamorphosed during an intense Neoproterozoic (Pan-African) event at around 630 Ma together with tectonically interlayered and widespread 800–650 Ma granitoid gneisses and minor clastic metasediments. The 800–650 Ma granitoids were derived predominantly from Neoproterozoic juvenile melts. There is no evidence for pre-800 Ma deformation. The 630 Ma event led to extensive migmatization in all gneisses and caused local melting. Similarities in age and tectonometamorphic evolution between these rocks and similar gneisses in northern Mozambique and southern Malawi suggest a similar geological evolution. However, distinctly different ages for the peak of metamorphism in Tanzania, Malawi and Mozambique indicate diachronous high-grade events that may be associated with terrane accretion and continental collision during orogenesis and favour the view that East Gondwana was not a coherent block during formation of the Gondwana supercontinent.
DOI: 10.6084/m9.figshare.3454172.v1
title: Single-zircon geochronology and Nd isotopic systematics of Proterozoic high-grade rocks from the Mozambique belt of southern Tanzania (Masasi area): implications for Gondwana assembly

description: The Mozambique belt of southern Tanzania is underlain by locally restricted 1100–950 Ma (late Kibaran) granitoid gneisses that were derived from remelting of Archaean continental crust, as suggested by Nd isotopic systematics. These rocks were deformed and metamorphosed during an intense Neoproterozoic (Pan-African) event at around 630 Ma together with tectonically interlayered and widespread 800–650 Ma granitoid gneisses and minor clastic metasediments. The 800–650 Ma granitoids were derived predominantly from Neoproterozoic juvenile melts. There is no evidence for pre-800 Ma deformation. The 630 Ma event led to extensive migmatization in all gneisses and caused local melting. Similarities in age and tectonometamorphic evolution between these rocks and similar gneisses in northern Mozambique and southern Malawi suggest a similar geological evolution. However, distinctly different ages for the peak of metamorphism in Tanzania, Malawi and Mozambique indicate diachronous high-grade events that may be associated with terrane accretion and continental collision during orogenesis and favour the view that East Gondwana was not a coherent block during formation of the Gondwana supercontinent.
DOI: 10.6084/m9.figshare.3454169
title: Basement evolution of the Sierra de la Ventana Fold Belt: new evidence for Cambrian continental rifting along the southern margin of Gondwana

description: U–Pb sensitive high-resolution ion microprobe data together with geochemical and Nd isotope analyses obtained in the basement complex of the Sierra de la Ventana Fold Belt indicate that the Early Palaeozoic passive margin history of the basin followed Cambrian magmatism related to rifting in a 600 Ma Neoproterozoic crust. The Cambrian episode started with intrusion of 531 ± 4 and 524 ± 5 Ma A- and I-type granites derived from a dehydrated infracrustal source (<em>ε</em>Nd<sub>530</sub> −3.1 to −5.9), and culminated with eruption of high-Zr peralkaline spherulitic rhyolites derived from an undepleted lithospheric mantle (509 ± 5 Ma; <em>ε</em>Nd<sub>509</sub> +0.5 to +1.0). These rift-related magmatic rocks were covered by shelf sediments deposited along a once-continuous passive margin, encompassing the Sierra de la Ventana Fold Belt, the Cape Fold Belt, the Falkland/Malvinas microplate and the Ellsworth Mountains block in Antarctica. The Cambrian rifting event defined the outline shape of the southern part of Gondwana, and can be regarded as the initiation of the supercontinent stage, which lasted until Jurassic break-up. The conjugate continental fragments separated from Gondwana during the Cambrian rifting could be the source for microcontinents with <em>c</em>. 1000 Ma basement rocks that collided with the proto-Andean margin during Ordovician–Silurian times.
DOI: 10.6084/m9.figshare.3454169.v1
title: Basement evolution of the Sierra de la Ventana Fold Belt: new evidence for Cambrian continental rifting along the southern margin of Gondwana

description: U–Pb sensitive high-resolution ion microprobe data together with geochemical and Nd isotope analyses obtained in the basement complex of the Sierra de la Ventana Fold Belt indicate that the Early Palaeozoic passive margin history of the basin followed Cambrian magmatism related to rifting in a 600 Ma Neoproterozoic crust. The Cambrian episode started with intrusion of 531 ± 4 and 524 ± 5 Ma A- and I-type granites derived from a dehydrated infracrustal source (<em>ε</em>Nd<sub>530</sub> −3.1 to −5.9), and culminated with eruption of high-Zr peralkaline spherulitic rhyolites derived from an undepleted lithospheric mantle (509 ± 5 Ma; <em>ε</em>Nd<sub>509</sub> +0.5 to +1.0). These rift-related magmatic rocks were covered by shelf sediments deposited along a once-continuous passive margin, encompassing the Sierra de la Ventana Fold Belt, the Cape Fold Belt, the Falkland/Malvinas microplate and the Ellsworth Mountains block in Antarctica. The Cambrian rifting event defined the outline shape of the southern part of Gondwana, and can be regarded as the initiation of the supercontinent stage, which lasted until Jurassic break-up. The conjugate continental fragments separated from Gondwana during the Cambrian rifting could be the source for microcontinents with <em>c</em>. 1000 Ma basement rocks that collided with the proto-Andean margin during Ordovician–Silurian times.
DOI: 10.6084/m9.figshare.3454166
title: The structural geometry, metamorphic and magmatic evolution of the Everest massif, High Himalaya of Nepal–South Tibet

description: This paper presents a new geological map together with cross-sections and lateral sections of the Everest massif. We combine field relations, structural geology, petrology, thermobarometry and geochronology to interpret the tectonic evolution of the Everest Himalaya. Lithospheric convergence of India and Asia since collision at <em>c.</em> 50 Ma. resulted in horizontal shortening, crustal thickening and regional metamorphism in the Himalaya and beneath southern Tibet. High temperatures (&gt;620 °C) during sillimanite grade metamorphism were maintained for 15 million years from 32 to 16.9 ± 0.5 Ma along the top of the Greater Himalayan slab. This implies that crustal thickening must also have been active during this time, which in turn suggests high topography during the Oligocene–early Miocene. Two low-angle normal faults cut the Everest massif at the top of the Greater Himalayan slab. The earlier, lower Lhotse detachment bounds the upper limit of massive leucogranite sills and sillimanite–cordierite gneisses, and has been locally folded. Ductile motion along the top of the Greater Himalayan slab was active from 18 to 16.9 Ma. The upper Qomolangma detachment is exposed in the summit pyramid of Everest and dips north at angles of less than 15°. Brittle faulting along the Qomolangma detachment, which cuts all leucogranites in the footwall, was post-16 Ma. Footwall sillimanite gneisses and leucogranites are exposed along the Kharta valley up to 57 km north of the Qomolangma detachment exposure near the summit of Everest. The amount of extrusion of footwall gneisses and leucogranites must have been around 200 km southwards, from an origin at shallow levels (12–18 km depth) beneath Tibet, supporting models of ductile extrusion of the Greater Himalayan slab. The Everest–Lhotse–Nuptse massif contains a massive ballooning sill of garnet + muscovite + tourmaline leucogranite up to 3000 m thick, which reaches 7800 m on the Kangshung face of Everest and on the south face of Nuptse, and is mainly responsible for the extreme altitude of both mountains. The middle crust beneath southern Tibet is inferred to be a weak, ductile-deforming zone of high heat and low friction separating a brittle deforming upper crust above from a strong (?granulite facies) lower crust with a rheologically strong upper mantle. Field evidence, thermobarometry and U–Pb geochronological data from the Everest Himalaya support the general shear extrusive flow of a mid-crustal channel from beneath the Tibetan plateau. The ending of high temperature metamorphism in the Himalaya and of ductile shearing along both the Main Central Thrust and the South Tibetan Detachment normal faults roughly coincides with initiation of strike-slip faulting and east–west extension in south Tibet (&lt;18 Ma).
DOI: 10.6084/m9.figshare.3454166.v1
title: The structural geometry, metamorphic and magmatic evolution of the Everest massif, High Himalaya of Nepal–South Tibet

description: This paper presents a new geological map together with cross-sections and lateral sections of the Everest massif. We combine field relations, structural geology, petrology, thermobarometry and geochronology to interpret the tectonic evolution of the Everest Himalaya. Lithospheric convergence of India and Asia since collision at <em>c.</em> 50 Ma. resulted in horizontal shortening, crustal thickening and regional metamorphism in the Himalaya and beneath southern Tibet. High temperatures (&gt;620 °C) during sillimanite grade metamorphism were maintained for 15 million years from 32 to 16.9 ± 0.5 Ma along the top of the Greater Himalayan slab. This implies that crustal thickening must also have been active during this time, which in turn suggests high topography during the Oligocene–early Miocene. Two low-angle normal faults cut the Everest massif at the top of the Greater Himalayan slab. The earlier, lower Lhotse detachment bounds the upper limit of massive leucogranite sills and sillimanite–cordierite gneisses, and has been locally folded. Ductile motion along the top of the Greater Himalayan slab was active from 18 to 16.9 Ma. The upper Qomolangma detachment is exposed in the summit pyramid of Everest and dips north at angles of less than 15°. Brittle faulting along the Qomolangma detachment, which cuts all leucogranites in the footwall, was post-16 Ma. Footwall sillimanite gneisses and leucogranites are exposed along the Kharta valley up to 57 km north of the Qomolangma detachment exposure near the summit of Everest. The amount of extrusion of footwall gneisses and leucogranites must have been around 200 km southwards, from an origin at shallow levels (12–18 km depth) beneath Tibet, supporting models of ductile extrusion of the Greater Himalayan slab. The Everest–Lhotse–Nuptse massif contains a massive ballooning sill of garnet + muscovite + tourmaline leucogranite up to 3000 m thick, which reaches 7800 m on the Kangshung face of Everest and on the south face of Nuptse, and is mainly responsible for the extreme altitude of both mountains. The middle crust beneath southern Tibet is inferred to be a weak, ductile-deforming zone of high heat and low friction separating a brittle deforming upper crust above from a strong (?granulite facies) lower crust with a rheologically strong upper mantle. Field evidence, thermobarometry and U–Pb geochronological data from the Everest Himalaya support the general shear extrusive flow of a mid-crustal channel from beneath the Tibetan plateau. The ending of high temperature metamorphism in the Himalaya and of ductile shearing along both the Main Central Thrust and the South Tibetan Detachment normal faults roughly coincides with initiation of strike-slip faulting and east–west extension in south Tibet (&lt;18 Ma).
DOI: 10.6084/m9.figshare.3454163
title: Reconstructing the Siluro-Devonian coastline of Gondwana: insights from the sedimentology of the Port Stephens Formation, Falkland Islands

description: Silurian and lower Devonian sedimentary successions are uncommon within the remnants of Gondwana. The Port Stephens Formation, the basal unit of the middle Palaeozoic West Falkland Group, presents a rare opportunity to study Gondwanan material of Siluro-Devonian age. The formation on West Falkland is <em>c</em>. 2560 m thick and consists of five members: Plantation, Albemarle, Mount Alice, South Harbour and Fish Creek. Thirty-five lithofacies are defined using variations in grain size and bedding characteristics. The distribution of these lithofacies and their associated ichnofacies between the various members lead us to suggest terrestrial and shallow marine deposition on an extensive, gently shelving alluvial to coastal plain. Vertical facies trends through the Port Stephens Formation, and into the base of the overlying Fox Bay Formation, record a complex superposition of subenvironments within a distinct overall transgressive–regressive–transgressive pattern, with the bulk of sediment accumulating during the regressive phase. Palaeocurrents indicate a basin to the present-day NE throughout. These results, together with lithostratigraphic correlations between the Port Stephens Formation and the Nardouw Subgroup in South Africa, are consistent with a reconstructed position off eastern South Africa and on the palaeo-Pacific margin of Gondwana, requiring a near-180° rotation of the Falkland Island microplate during break-up, in agreement with previous models. We suggest that global changes in sea level during the mid–late Silurian and early Devonian strongly influenced changes in the depositional environment. Enhanced erosion of the continental margin and extensive sediment bypass during the regressive phase of this cycle could help to explain the low abundance of preserved Gondwanan material of this age.
DOI: 10.6084/m9.figshare.3454163.v1
title: Reconstructing the Siluro-Devonian coastline of Gondwana: insights from the sedimentology of the Port Stephens Formation, Falkland Islands

description: Silurian and lower Devonian sedimentary successions are uncommon within the remnants of Gondwana. The Port Stephens Formation, the basal unit of the middle Palaeozoic West Falkland Group, presents a rare opportunity to study Gondwanan material of Siluro-Devonian age. The formation on West Falkland is <em>c</em>. 2560 m thick and consists of five members: Plantation, Albemarle, Mount Alice, South Harbour and Fish Creek. Thirty-five lithofacies are defined using variations in grain size and bedding characteristics. The distribution of these lithofacies and their associated ichnofacies between the various members lead us to suggest terrestrial and shallow marine deposition on an extensive, gently shelving alluvial to coastal plain. Vertical facies trends through the Port Stephens Formation, and into the base of the overlying Fox Bay Formation, record a complex superposition of subenvironments within a distinct overall transgressive–regressive–transgressive pattern, with the bulk of sediment accumulating during the regressive phase. Palaeocurrents indicate a basin to the present-day NE throughout. These results, together with lithostratigraphic correlations between the Port Stephens Formation and the Nardouw Subgroup in South Africa, are consistent with a reconstructed position off eastern South Africa and on the palaeo-Pacific margin of Gondwana, requiring a near-180° rotation of the Falkland Island microplate during break-up, in agreement with previous models. We suggest that global changes in sea level during the mid–late Silurian and early Devonian strongly influenced changes in the depositional environment. Enhanced erosion of the continental margin and extensive sediment bypass during the regressive phase of this cycle could help to explain the low abundance of preserved Gondwanan material of this age.
DOI: 10.6084/m9.figshare.3454160
title: Salt weathering: a selective review

description: The past decade has seen a growing scientific interest in the still poorly understood subject of salt weathering, a phenomenon with significant cultural and economic consequences. This interest has led to an increase in research results and growing clarification of the roles salts play in weathering and decay. The development of improved mitigation methods to reduce the decay of building materials by salts has been a slow process, often arising from the analysis of unique field situations and otherwise dependent on simplified laboratory experiments and computer modelling. Collecting, reviewing, synthesizing and disseminating the existing data on salt weathering is a difficult task. The size and scope of the topic are mirrored in the diverse disciplines that have historically contributed to understanding the action of salts in porous materials and mitigation methods. Nevertheless, an appreciation of existing, even contradictory, data is an important tool for increasing understanding. There are now over 1800 research articles on the topic of salt weathering originating from several disciplines, as well as over 6000 references on the general problems of building material decay. In order to navigate such a vast collection of data and knowledge, this article describes the multidisciplinary nature of the study of salt damage to porous building materials, provides a framework for considering the complexity of salt damage, and serves as a selective literature survey largely focused on recent work and those articles with relevance for conservation.
DOI: 10.6084/m9.figshare.3454160.v1
title: Salt weathering: a selective review

description: The past decade has seen a growing scientific interest in the still poorly understood subject of salt weathering, a phenomenon with significant cultural and economic consequences. This interest has led to an increase in research results and growing clarification of the roles salts play in weathering and decay. The development of improved mitigation methods to reduce the decay of building materials by salts has been a slow process, often arising from the analysis of unique field situations and otherwise dependent on simplified laboratory experiments and computer modelling. Collecting, reviewing, synthesizing and disseminating the existing data on salt weathering is a difficult task. The size and scope of the topic are mirrored in the diverse disciplines that have historically contributed to understanding the action of salts in porous materials and mitigation methods. Nevertheless, an appreciation of existing, even contradictory, data is an important tool for increasing understanding. There are now over 1800 research articles on the topic of salt weathering originating from several disciplines, as well as over 6000 references on the general problems of building material decay. In order to navigate such a vast collection of data and knowledge, this article describes the multidisciplinary nature of the study of salt damage to porous building materials, provides a framework for considering the complexity of salt damage, and serves as a selective literature survey largely focused on recent work and those articles with relevance for conservation.
DOI: 10.6084/m9.figshare.3454157
title: Source of the Dalradian Supergroup constrained by U–Pb dating of detrital zircon and implications for the East Laurentian margin

description: Detrital zircons in siliciclastic units of the Dalradian Supergroup yield U–Pb ages ranging from 3.2 to 0.5 Ga. Detrital zircons from the sub-Grampian Group basement and the Grampian Group are predominantly of Palaeoproterozoic and Mesoproterozoic ages with Archaean grains absent or rare. In contrast, the overlying Appin, Argyll and Southern Highland groups contain a significant contribution of Archaean detrital zircon grains, some of which locally preserve evidence for late Palaeoproterozoic overgrowths dated at <em>c</em>. 1.8 Ga. In addition, on concordia plots Archaean grains are slightly discordant with a lower intercept at <em>c</em>. 1.8 Ga suggesting they were affected by a tectonothermal event at this time. Late Palaeoproterozoic and Mesoproterozoic grains also show evidence for overprinting by a tectonothermal event around 1.0–0.9 Ga. These tectonothermal events occurred in the source region before accumulation of the siliciclastic detritus. The analysed samples contained no definitive evidence for having been affected by a late Neoproterozoic (Knoydartian) event or of containing detritus derived from a source showing evidence for this event. The overall age range of detritus, combined with sparse palaeocurrent data, is consistent with derivation from the Laurentian foreland, especially the Labrador–Greenland region. Archaean detritus overlaps with that of Archaean cratons, notably the Superior, whereas Palaeoproterozoic detritus corresponds to the timing of suturing of Archaean cratons by a series of orogenic belts (Ketilidian–Makkovik, New Quebec, Nagssugtoqidian, Torngat belts). Mesoproterozoic detritus is consistent with derivation from the Grenville Orogen. The presence of a series of detrital age peaks in the late Palaeoproterozoic and early Mesoproterozoic (1.8–1.5 Ga), the paucity of mid-Mesoproterozoic detritus (1.4–1.2 Ga), and evidence for a tectonothermal event between 1.0 and 0.9 Ga is typical of the geological history of the Labrador–Greenland region of Laurentia.