cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.3454925
title: Basin architecture and growth folding of the NW Zagros early foreland basin during the Late Cretaceous and early Tertiary

description: We present and use the chronostratigraphy of 13 field logs and detailed mapping to constrain the evolution of the early Zagros foreland basin, in NW Iran. Large foraminifera, calcareous nannofossil, palynological and <sup>87</sup>Sr/<sup>86</sup>Sr analysis supplied ages indicating a Campanian–early Eocene age of the basin infill, which is characterizd by a diachronous, southwestward migrating, shallowing upwards, mixed clastic–carbonate succession. Growth synclines and local palaeoslope variations indicate syndepositional folding from Maastrichtian to Eocene time and suggest forelandward migration of the deformation front. We also illustrate the basin architecture with a synthetic stratigraphic transect. From internal to external areas, time lines cross the formation boundaries from continental Kashkan red beds to Taleh Zang mixed clastic–carbonate platforms, Amiran slope deposits and basinal Gurpi–Pabdeh shales and marls. The foreland basin depocentres show a progressive migration from the Campanian to Eocene (<em>c</em>. 83–52.7 Ma), with rates of <em>c</em>. 2.4 mm a<sup>−1</sup> during the early–middle Palaeocene (<em>c</em>. 65.5–58.7 Ma) increasing to <em>c</em>. 6 mm a<sup>−1</sup> during the late Palaeocene–earliest Eocene (<em>c</em>. 58.7–52.8 Ma). Coeval subsidence remained at <em>c</em>. 0.27 mm a<sup>−1</sup> during the first 12.7 Ma and decreased to <em>c</em>. 0.16 mm a<sup>−1</sup> during the last 4.2 Ma of basin filling. Finally, we integrate our results with published large-scale maps and discuss their implications in the context of the Zagros orogeny.
DOI: 10.6084/m9.figshare.3454925.v1
title: Basin architecture and growth folding of the NW Zagros early foreland basin during the Late Cretaceous and early Tertiary

description: We present and use the chronostratigraphy of 13 field logs and detailed mapping to constrain the evolution of the early Zagros foreland basin, in NW Iran. Large foraminifera, calcareous nannofossil, palynological and <sup>87</sup>Sr/<sup>86</sup>Sr analysis supplied ages indicating a Campanian–early Eocene age of the basin infill, which is characterizd by a diachronous, southwestward migrating, shallowing upwards, mixed clastic–carbonate succession. Growth synclines and local palaeoslope variations indicate syndepositional folding from Maastrichtian to Eocene time and suggest forelandward migration of the deformation front. We also illustrate the basin architecture with a synthetic stratigraphic transect. From internal to external areas, time lines cross the formation boundaries from continental Kashkan red beds to Taleh Zang mixed clastic–carbonate platforms, Amiran slope deposits and basinal Gurpi–Pabdeh shales and marls. The foreland basin depocentres show a progressive migration from the Campanian to Eocene (<em>c</em>. 83–52.7 Ma), with rates of <em>c</em>. 2.4 mm a<sup>−1</sup> during the early–middle Palaeocene (<em>c</em>. 65.5–58.7 Ma) increasing to <em>c</em>. 6 mm a<sup>−1</sup> during the late Palaeocene–earliest Eocene (<em>c</em>. 58.7–52.8 Ma). Coeval subsidence remained at <em>c</em>. 0.27 mm a<sup>−1</sup> during the first 12.7 Ma and decreased to <em>c</em>. 0.16 mm a<sup>−1</sup> during the last 4.2 Ma of basin filling. Finally, we integrate our results with published large-scale maps and discuss their implications in the context of the Zagros orogeny.
DOI: 10.6084/m9.figshare.3454922
title: Origin of the Aves Ridge and Dutch–Venezuelan Antilles: interaction of the Cretaceous ‘Great Arc' and Caribbean–Colombian Oceanic Plateau?

description: In this paper we reassess the geochronology and geochemistry of three dredge hauls from the SE corner of the Aves Ridge (Caribbean Sea) originally sampled in 1968 by Duke University's R.V. <em>Eastward</em>. Two hauls consist of light rare earth element-enriched granitoids with a U–Pb zircon emplacement age of 75.9 ± 0.7 Ma. A further haul contains mostly calc-alkaline island arc basaltic andesites of uncertain age. Petrological, trace element and isotopic constraints indicate that the granitoids have an oceanic crustal source and were formed by melting of the lower arc, oceanic or oceanic plateau crust. The mafic rocks formed by partial melting of an incompatible trace element-enriched mantle wedge, which was probably composed of mantle plume material. Both the dredged rocks and data from the Dutch–Venezuelan Antilles indicate a period of west-dipping underthrusting and subduction beneath, or close to, the Caribbean–Colombian Oceanic Plateau between <em>c</em>. 88 and <em>c</em>. 59 Ma, concurrent with collision of part of the plateau with northwestern South America. Constraints from the geochemistry and geochronology of offshore southern Caribbean arc and plateau rocks suggest that in the southern Caribbean there was no pre-existing west-dipping subduction system during formation of the Caribbean–Colombian Oceanic Plateau, whereas long-lived SW-dipping subduction in the northern Greater Antilles is more probable.
DOI: 10.6084/m9.figshare.3454922.v1
title: Origin of the Aves Ridge and Dutch–Venezuelan Antilles: interaction of the Cretaceous ‘Great Arc' and Caribbean–Colombian Oceanic Plateau?

description: In this paper we reassess the geochronology and geochemistry of three dredge hauls from the SE corner of the Aves Ridge (Caribbean Sea) originally sampled in 1968 by Duke University's R.V. <em>Eastward</em>. Two hauls consist of light rare earth element-enriched granitoids with a U–Pb zircon emplacement age of 75.9 ± 0.7 Ma. A further haul contains mostly calc-alkaline island arc basaltic andesites of uncertain age. Petrological, trace element and isotopic constraints indicate that the granitoids have an oceanic crustal source and were formed by melting of the lower arc, oceanic or oceanic plateau crust. The mafic rocks formed by partial melting of an incompatible trace element-enriched mantle wedge, which was probably composed of mantle plume material. Both the dredged rocks and data from the Dutch–Venezuelan Antilles indicate a period of west-dipping underthrusting and subduction beneath, or close to, the Caribbean–Colombian Oceanic Plateau between <em>c</em>. 88 and <em>c</em>. 59 Ma, concurrent with collision of part of the plateau with northwestern South America. Constraints from the geochemistry and geochronology of offshore southern Caribbean arc and plateau rocks suggest that in the southern Caribbean there was no pre-existing west-dipping subduction system during formation of the Caribbean–Colombian Oceanic Plateau, whereas long-lived SW-dipping subduction in the northern Greater Antilles is more probable.
DOI: 10.6084/m9.figshare.3454919
title: The characteristics of rare earth elements in bulk precipitation, throughfall, foliage and lichens in the Lesní potok catchment and its vicinity, Czech Republic

description: <strong>ABSTRACT</strong> A comparison of rare earth elements' (REE) atmospheric signatures in various ecosystem compartments was carried out in the vicinity of the Lesní potok catchment (LP), Czech Republic. REE signatures were investigated from 2004 to 2006 in rainwater, throughfall, tree foliage (<em>Picea abies</em>, <em>Fagus sylvatica</em>) and lichens (<em>Hypogymnia physodes</em>) for selected elements (Al, Ca, Fe, K, Mg, Mn, Na, P, S, Si). REE concentrations increased in the following sequences: bulk precipitation &lt; beech throughfall &lt; spruce throughfall and spruce needles &lt; beech leaves ≪ lichens.
DOI: 10.6084/m9.figshare.3454919.v1
title: The characteristics of rare earth elements in bulk precipitation, throughfall, foliage and lichens in the Lesní potok catchment and its vicinity, Czech Republic

description: <strong>ABSTRACT</strong> A comparison of rare earth elements' (REE) atmospheric signatures in various ecosystem compartments was carried out in the vicinity of the Lesní potok catchment (LP), Czech Republic. REE signatures were investigated from 2004 to 2006 in rainwater, throughfall, tree foliage (<em>Picea abies</em>, <em>Fagus sylvatica</em>) and lichens (<em>Hypogymnia physodes</em>) for selected elements (Al, Ca, Fe, K, Mg, Mn, Na, P, S, Si). REE concentrations increased in the following sequences: bulk precipitation &lt; beech throughfall &lt; spruce throughfall and spruce needles &lt; beech leaves ≪ lichens.
DOI: 10.6084/m9.figshare.3454916
title: Phase equilibrium constraints on conditions of granulite-facies metamorphism at Scourie, NW Scotland

description: The metamorphic evolution of a metapyroxenite and metagabbro from Scourie, NW Scotland, is investigated using phase equilibria modelled in the NCFMASHTO (Na<sub>2</sub>O–CaO–FeO–MgO–Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub>–H<sub>2</sub>O–TiO<sub>2</sub>–O) system. The calculated stability fields for the observed assemblages in each rock overlap and imply conditions of 8.5–11.5 kbar and 875–975 °C for the peak of granulite-facies (Badcallian) metamorphism. The lack of any evidence for the former presence of garnet in the metapyroxenite suggests that the rocks cannot have reached pressures much in excess of those recorded at the metamorphic peak. The growth of coronas of plagioclase, orthopyroxene and magnetite replacing garnet in the metagabbro is consistent with near-isothermal retrograde decompression from the metamorphic peak to pressures of 7–9 kbar. The constraints on the pressure–temperature evolution imposed by the modelled phase equilibria are more consistent with a process of crustal growth dominated by magmatic accretion rather than by significant tectonic thickening during the early Scourian.
DOI: 10.6084/m9.figshare.3454916.v1
title: Phase equilibrium constraints on conditions of granulite-facies metamorphism at Scourie, NW Scotland

description: The metamorphic evolution of a metapyroxenite and metagabbro from Scourie, NW Scotland, is investigated using phase equilibria modelled in the NCFMASHTO (Na<sub>2</sub>O–CaO–FeO–MgO–Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub>–H<sub>2</sub>O–TiO<sub>2</sub>–O) system. The calculated stability fields for the observed assemblages in each rock overlap and imply conditions of 8.5–11.5 kbar and 875–975 °C for the peak of granulite-facies (Badcallian) metamorphism. The lack of any evidence for the former presence of garnet in the metapyroxenite suggests that the rocks cannot have reached pressures much in excess of those recorded at the metamorphic peak. The growth of coronas of plagioclase, orthopyroxene and magnetite replacing garnet in the metagabbro is consistent with near-isothermal retrograde decompression from the metamorphic peak to pressures of 7–9 kbar. The constraints on the pressure–temperature evolution imposed by the modelled phase equilibria are more consistent with a process of crustal growth dominated by magmatic accretion rather than by significant tectonic thickening during the early Scourian.
DOI: 10.6084/m9.figshare.3454910
title: Magma mixing and unmixing related mineralization in the Karacaali Magmatic Complex, central Anatolia, Turkey

description: The calc-alkaline Karacaali Magmatic Complex (KMC), in the Central Anatolian Crystalline Complex, is an example of an Upper Cretaceous post-collisional I-type, plutonic–volcanic association. Volcanic rocks grade from basalt to rhyolite, whilst coeval plutonic rocks range from gabbro to leucogranite. In this paper we document evidence for the occurrence of both mixing and unmixing during the evolution of this igneous complex. Mixing of mafic and felsic magmas was observed in petrographic properties at microscopic to macroscopic scales and is further supported by mineral chemistry data. The occurrence of unmixing is evidenced in the Fe and Cu–Mo mineralization hosted in the KMC. The iron mineralization in basaltic-andesitic rocks consists mostly of magnetite. Magnetite has been grouped into four settings: (1) matrix type; (2) vein-filling type; (3) breccia matrix type; and (4) vesicle-filling type. In contrast, Cu–Mo mineralization is related to vertical north–south trending quartz-, quartz-calcite-, and quartz-tourmaline veins crosscutting monzonitic and granitic rocks. We propose that the intrusion of an oxidized, Fe- and Cu-rich basic magma into a partially crystallized acid magma resulted in partial mixing and may have triggered the abrupt separation of an iron-oxide-rich melt. Our results highlight the importance of magma mixing and metal unmixing, possibly associated with stress relaxation during post-collisional evolution.
DOI: 10.6084/m9.figshare.3454910.v1
title: Magma mixing and unmixing related mineralization in the Karacaali Magmatic Complex, central Anatolia, Turkey

description: The calc-alkaline Karacaali Magmatic Complex (KMC), in the Central Anatolian Crystalline Complex, is an example of an Upper Cretaceous post-collisional I-type, plutonic–volcanic association. Volcanic rocks grade from basalt to rhyolite, whilst coeval plutonic rocks range from gabbro to leucogranite. In this paper we document evidence for the occurrence of both mixing and unmixing during the evolution of this igneous complex. Mixing of mafic and felsic magmas was observed in petrographic properties at microscopic to macroscopic scales and is further supported by mineral chemistry data. The occurrence of unmixing is evidenced in the Fe and Cu–Mo mineralization hosted in the KMC. The iron mineralization in basaltic-andesitic rocks consists mostly of magnetite. Magnetite has been grouped into four settings: (1) matrix type; (2) vein-filling type; (3) breccia matrix type; and (4) vesicle-filling type. In contrast, Cu–Mo mineralization is related to vertical north–south trending quartz-, quartz-calcite-, and quartz-tourmaline veins crosscutting monzonitic and granitic rocks. We propose that the intrusion of an oxidized, Fe- and Cu-rich basic magma into a partially crystallized acid magma resulted in partial mixing and may have triggered the abrupt separation of an iron-oxide-rich melt. Our results highlight the importance of magma mixing and metal unmixing, possibly associated with stress relaxation during post-collisional evolution.
DOI: 10.6084/m9.figshare.3454907
title: Integrating streamer and ocean-bottom seismic data for sub-basalt imaging on the Atlantic Margin

description: <strong>ABSTRACT</strong> Stacked basalt flows cover much of the NW European continental margin, including potentially prospective sediments of the Faroes shelf. Such flows attenuate seismic energy, hindering sub-basalt structural imaging which is critical for both exploration and tectonic studies. Low-frequency, long-offset reflection surveys have yielded improved images below top basalt, while coincident ocean-bottom seismometer (OBS) data have mapped low velocity zones (LVZ) from tomographic inversion. Image correlation in a common depth domain is challenged by low spatial resolution of the tomographic image, the absence of turning rays in a LVZ and the lack of wide-angle arrivals in the reflection data. We integrate densely sampled reflection data with deep velocities from OBS data to give a common velocity model in a new, iterated, pre-stack depth-migration workflow using complementary constraints from the two datasets. The matched velocity model and depth image enable interpretation of (i) a uniform flood basalt sequence, 2–4 km thick beneath the Fugloy Ridge, with velocities correlating with those in the Lopra 1/1A borehole and (ii) a sub-basalt LVZ with chaotic reflections corresponding to sill-intruded, probably syn-rift sediments. Such a workflow could be extended to targets beneath high velocity salt or basalt and could provide constraints for 3D datasets.
DOI: 10.6084/m9.figshare.3454901
title: Evolution of the Archaean Karelian Province in the Fennoscandian Shield in the light of U–Pb zircon ages and Sm–Nd and Lu–Hf isotope systematics

description: <em>In situ</em> Lu–Hf (laser ablation microprobe–inductively coupled plasma mass spectrometry (LAM-ICPMS)) and U–Pb (LAM-ICPMS, secondary ionization mass spectrometry (SIMS)) analyses of zircon, and whole-rock Sm–Nd isotope analyses were performed on rocks formed during magmatic events in three Archaean complexes in the Karelian Province of Fennoscandia (Pudasjärvi, Koillismaa and Iisalmi). These complexes have U–Pb ages ranging from 3.5 to 2.6 Ga. In Pudasjärvi, sparse xenocrystic cores give ages of 3.6–3.7 Ga and initial <sup>176</sup>Hf/<sup>177</sup>Hf suggesting influence of a crustal component T ≥ 4.0 Ga (assuming a CHUR-like mantle source). Ages and Nd and Hf isotope patterns indicate magmatic events at 3.6–3.7 Ga (Siurua, Pudasjärvi with ≥4.0 Ga precursor), 3.2 Ga (Iisalmi, Koillismaa), 2.8 Ga (Pudasjärvi) and 2.7 Ga (Pudasjärvi, Iisalmi). In the Meso- and Palaeoarchaean events, there is no evidence of sources equivalent to present-day depleted mantle; such sources were, however, involved in the 2.8–2.7 Ga events. ε<sub>Hf</sub> and ε<sub>Nd</sub> are strongly correlated. Contrasts between the Archaean complexes indicate that they evolved separately until <em>c</em>. 2.7 Ga. The age and ε<sub>Hf</sub> pattern of ≤2.8 Ga rocks in the Karelian Province is compatible with a scenario in which the Karelia, Superior, Yilgarn and Slave cratons were part of a late Archaean supercontinent, but does not constitute proof of the existence of such a supercontinent.
DOI: 10.6084/m9.figshare.3454898
title: Testing rival tectonic uplift models for the Lechaion Gulf in the Gulf of Corinth rift

description: The Gulf of Corinth, central Greece, is a rapidly extending continental rift, the eastern part of which bifurcates into the active northern Alkyonides Gulf and the southern Lechaion Gulf. The Lechaion Gulf is considered an inactive relict of early rifting, yet the presence of late Quaternary shorelines is evidence of continuing uplift of the north, east and south margins of this basin. Models to explain uplift include uplift on the footwall of the southern Alkyonides Gulf fault system and the Xylocastro–Perachora faults or ‘regional' isostatic uplift independent of fault slip. These models are tested by comparing predicted spatial uplift trends with those observed. Uplift rates since Marine Isotope Stage 7 of 0.31 ± 0.04 mm a<sup>−1</sup> on the Lechaion Gulf north coast are explained as displacement on the footwall of active faults. However, the south coast uplift cannot be explained by footwall uplift and is evidence for isostatic uplift that probably affects the whole of the southern Gulf of Corinth rift. Isostatic uplift rates of 0.22 ± 0.01 mm a<sup>−1</sup> at the Corinth canal increase westward towards the mouth of the Lechaion Gulf where it meets the modern rift, the Gulf of Corinth.
DOI: 10.6084/m9.figshare.3454901.v1
title: Evolution of the Archaean Karelian Province in the Fennoscandian Shield in the light of U–Pb zircon ages and Sm–Nd and Lu–Hf isotope systematics

description: <em>In situ</em> Lu–Hf (laser ablation microprobe–inductively coupled plasma mass spectrometry (LAM-ICPMS)) and U–Pb (LAM-ICPMS, secondary ionization mass spectrometry (SIMS)) analyses of zircon, and whole-rock Sm–Nd isotope analyses were performed on rocks formed during magmatic events in three Archaean complexes in the Karelian Province of Fennoscandia (Pudasjärvi, Koillismaa and Iisalmi). These complexes have U–Pb ages ranging from 3.5 to 2.6 Ga. In Pudasjärvi, sparse xenocrystic cores give ages of 3.6–3.7 Ga and initial <sup>176</sup>Hf/<sup>177</sup>Hf suggesting influence of a crustal component T ≥ 4.0 Ga (assuming a CHUR-like mantle source). Ages and Nd and Hf isotope patterns indicate magmatic events at 3.6–3.7 Ga (Siurua, Pudasjärvi with ≥4.0 Ga precursor), 3.2 Ga (Iisalmi, Koillismaa), 2.8 Ga (Pudasjärvi) and 2.7 Ga (Pudasjärvi, Iisalmi). In the Meso- and Palaeoarchaean events, there is no evidence of sources equivalent to present-day depleted mantle; such sources were, however, involved in the 2.8–2.7 Ga events. ε<sub>Hf</sub> and ε<sub>Nd</sub> are strongly correlated. Contrasts between the Archaean complexes indicate that they evolved separately until <em>c</em>. 2.7 Ga. The age and ε<sub>Hf</sub> pattern of ≤2.8 Ga rocks in the Karelian Province is compatible with a scenario in which the Karelia, Superior, Yilgarn and Slave cratons were part of a late Archaean supercontinent, but does not constitute proof of the existence of such a supercontinent.
DOI: 10.6084/m9.figshare.3454898.v1
title: Testing rival tectonic uplift models for the Lechaion Gulf in the Gulf of Corinth rift

description: The Gulf of Corinth, central Greece, is a rapidly extending continental rift, the eastern part of which bifurcates into the active northern Alkyonides Gulf and the southern Lechaion Gulf. The Lechaion Gulf is considered an inactive relict of early rifting, yet the presence of late Quaternary shorelines is evidence of continuing uplift of the north, east and south margins of this basin. Models to explain uplift include uplift on the footwall of the southern Alkyonides Gulf fault system and the Xylocastro–Perachora faults or ‘regional' isostatic uplift independent of fault slip. These models are tested by comparing predicted spatial uplift trends with those observed. Uplift rates since Marine Isotope Stage 7 of 0.31 ± 0.04 mm a<sup>−1</sup> on the Lechaion Gulf north coast are explained as displacement on the footwall of active faults. However, the south coast uplift cannot be explained by footwall uplift and is evidence for isostatic uplift that probably affects the whole of the southern Gulf of Corinth rift. Isostatic uplift rates of 0.22 ± 0.01 mm a<sup>−1</sup> at the Corinth canal increase westward towards the mouth of the Lechaion Gulf where it meets the modern rift, the Gulf of Corinth.
DOI: 10.6084/m9.figshare.3454895
title: High-Mg andesite genesis by upper crustal differentiation

description: Whereas arc magmas typically undergo early degassing-induced crystallization and viscous stagnation at mid-crustal levels, hotter and less hydrous melts that are associated with elevated surface heat flux may experience delayed crystallization at shallower levels. Using MELTS modelling, we demonstrate here that high-Mg andesites, which have been regarded as particularly hydrous primary melts generated in equilibrium with mantle peridotite, can form by crystal fractionation from low-H<sub>2</sub>O primitive arc basalts in the upper crust. This is consistent with many characteristics previously attributed to their primary origin, including forsteritic olivines that contain chromite inclusions and lack significant reaction rims, and Cr-rich pyroxenes.
DOI: 10.6084/m9.figshare.3454895.v1
title: High-Mg andesite genesis by upper crustal differentiation

description: Whereas arc magmas typically undergo early degassing-induced crystallization and viscous stagnation at mid-crustal levels, hotter and less hydrous melts that are associated with elevated surface heat flux may experience delayed crystallization at shallower levels. Using MELTS modelling, we demonstrate here that high-Mg andesites, which have been regarded as particularly hydrous primary melts generated in equilibrium with mantle peridotite, can form by crystal fractionation from low-H<sub>2</sub>O primitive arc basalts in the upper crust. This is consistent with many characteristics previously attributed to their primary origin, including forsteritic olivines that contain chromite inclusions and lack significant reaction rims, and Cr-rich pyroxenes.