O. Dauteuil, M. Jolivet, Louis Gaudaré, Anne-Morwenn Pastier
We present an analysis of ground deformation induced by large‐scale seasonal rainfall in Southern Africa, based on GPS and GRACE time series and on simulations of elastic flexural response to hydrological loading. This large‐scale study including South Zambia, South Angola, North Namibia and North Botswana displays a latitudinal precipitation gradient between tropical to semi‐arid conditions. GRACE data display annual variations in water mass decreasing drastically southwards. GPS time series of three permanent stations located in Zambia, Namibia and Botswana show seasonal synchronous vertical displacements with amplitude decreasing southwards from 4 to 2 cm, with a shift of 2–3 months from the main rainfall season. Flexure simulations integrating rainfall, evapotranspiration, water storage, flood migration and river output produce a ground flexure up to 6 cm with timing in agreement with the GPS time series. It highlights the hydrological buffering of surface aquifer located in the Kalahari sands.
{"title":"Rainfall‐induced ground deformation in southern Africa","authors":"O. Dauteuil, M. Jolivet, Louis Gaudaré, Anne-Morwenn Pastier","doi":"10.1111/ter.12650","DOIUrl":"https://doi.org/10.1111/ter.12650","url":null,"abstract":"We present an analysis of ground deformation induced by large‐scale seasonal rainfall in Southern Africa, based on GPS and GRACE time series and on simulations of elastic flexural response to hydrological loading. This large‐scale study including South Zambia, South Angola, North Namibia and North Botswana displays a latitudinal precipitation gradient between tropical to semi‐arid conditions. GRACE data display annual variations in water mass decreasing drastically southwards. GPS time series of three permanent stations located in Zambia, Namibia and Botswana show seasonal synchronous vertical displacements with amplitude decreasing southwards from 4 to 2 cm, with a shift of 2–3 months from the main rainfall season. Flexure simulations integrating rainfall, evapotranspiration, water storage, flood migration and river output produce a ground flexure up to 6 cm with timing in agreement with the GPS time series. It highlights the hydrological buffering of surface aquifer located in the Kalahari sands.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"260 - 266"},"PeriodicalIF":2.4,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44815926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Bjerager, P. Alsen, J. Bojesen‐Koefoed, M. Fyhn, J. Hovikoski, Nynke Keulen, S. Lindström, J. Therkelsen, T. Thomsen
The Wandel Sea Basin in North Greenland was part of the epicontinental Boreal Sea in Triassic time. The basin formed the western margin of the northernmost Atlantic elongated sea connecting southwards with basins along the conjugate Greenland—Norwegian margins. A multidisciplinary dataset including sedimentology, biostratigraphy, organic geochemistry and sedimentary provenance, allow to document its basin evolution. The Wandel Sea Basin was transgressed in the Dienerian with marine deposition prevailing until the Norian. Sediments were mainly sourced from the Greenlandic Caledonian basement and deposited on a 100 km wide shallow marine shelf during the Early Triassic. In Middle Triassic, oil‐prone mudstones formed in oxygen‐depleted deep shelf settings, including eastern Wandel Sea Basin. Detrital zircon U–Pb ages show that by Carnian times, the >1000 km wide, Uralian‐sourced, deltaic shelf had prograded westward across the Barents Sea reaching the eastern north Greenland and de facto nearly closed the northernmost Atlantic Sea.
{"title":"Triassic in the northernmost Atlantic—Linking North Greenland and the southwestern Barents Sea","authors":"M. Bjerager, P. Alsen, J. Bojesen‐Koefoed, M. Fyhn, J. Hovikoski, Nynke Keulen, S. Lindström, J. Therkelsen, T. Thomsen","doi":"10.1111/ter.12649","DOIUrl":"https://doi.org/10.1111/ter.12649","url":null,"abstract":"The Wandel Sea Basin in North Greenland was part of the epicontinental Boreal Sea in Triassic time. The basin formed the western margin of the northernmost Atlantic elongated sea connecting southwards with basins along the conjugate Greenland—Norwegian margins. A multidisciplinary dataset including sedimentology, biostratigraphy, organic geochemistry and sedimentary provenance, allow to document its basin evolution. The Wandel Sea Basin was transgressed in the Dienerian with marine deposition prevailing until the Norian. Sediments were mainly sourced from the Greenlandic Caledonian basement and deposited on a 100 km wide shallow marine shelf during the Early Triassic. In Middle Triassic, oil‐prone mudstones formed in oxygen‐depleted deep shelf settings, including eastern Wandel Sea Basin. Detrital zircon U–Pb ages show that by Carnian times, the >1000 km wide, Uralian‐sourced, deltaic shelf had prograded westward across the Barents Sea reaching the eastern north Greenland and de facto nearly closed the northernmost Atlantic Sea.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"250 - 259"},"PeriodicalIF":2.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45141494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Davi F. Carvalho, A. Nogueira, M. Macambira, C. Lana, R. F. Santos, Julia Guélard, P. Sansjofre
Cap carbonates overlying Marinoan (635 Ma) glacial deposits worldwide record extreme paleoceanographic changes that may have triggered the rise of macroscopic life. However, the lack of geochronological constraints on these successions hinders reconciling climate and environmental change. Their upper part is marked by anomalous aragonite precipitation associated with large transgression and oxygenation of the post‐glacial ocean. Neomorphism of these deposits to low‐Mg calcite often includes centimetre‐scale seafloor crystal fans. We used in‐situ U–Pb dating and C and Sr isotopic analyses in the Puga cap carbonate to estimate the nature and timing of the neomorphism process. An age of 623 ± 3 [9] Ma (δ13C ~ −6‰ and 87Sr/87Sr ~ 0.7071–0.7075) for a blocky calcite cement is consistent with solution‐reprecipitation within the fans during final filling and diagenetic stabilization of the cap carbonate fabric. This result improves previous cap carbonate direct dating, providing a rare Lower Ediacaran chronostratigraphic reference.
{"title":"Constraining the diagenesis of the Puga cap carbonate from U–Pb in‐situ dating of seafloor crystal fans, southern Amazonian craton, Brazil","authors":"Davi F. Carvalho, A. Nogueira, M. Macambira, C. Lana, R. F. Santos, Julia Guélard, P. Sansjofre","doi":"10.1111/ter.12652","DOIUrl":"https://doi.org/10.1111/ter.12652","url":null,"abstract":"Cap carbonates overlying Marinoan (635 Ma) glacial deposits worldwide record extreme paleoceanographic changes that may have triggered the rise of macroscopic life. However, the lack of geochronological constraints on these successions hinders reconciling climate and environmental change. Their upper part is marked by anomalous aragonite precipitation associated with large transgression and oxygenation of the post‐glacial ocean. Neomorphism of these deposits to low‐Mg calcite often includes centimetre‐scale seafloor crystal fans. We used in‐situ U–Pb dating and C and Sr isotopic analyses in the Puga cap carbonate to estimate the nature and timing of the neomorphism process. An age of 623 ± 3 [9] Ma (δ13C ~ −6‰ and 87Sr/87Sr ~ 0.7071–0.7075) for a blocky calcite cement is consistent with solution‐reprecipitation within the fans during final filling and diagenetic stabilization of the cap carbonate fabric. This result improves previous cap carbonate direct dating, providing a rare Lower Ediacaran chronostratigraphic reference.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"276 - 284"},"PeriodicalIF":2.4,"publicationDate":"2023-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48516352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dimitrios Charlaftis, S. Jones, Lars Grimm, A. Kappler
Bacteria are the most abundant forms of life we know on our planet, able to survive in a variety of habitats, that play an important role in mineral formation and transformation processes. Here, we present laboratory experiments in which unconsolidated quartz grains were seeded with Geobacter sulfurreducens cells and exposed to a mineral medium solution for 96 hours at temperatures of between 60°C and 120°C. Experimental data show the interdependence between extracellular polymeric substances (EPS) and the early formation of grain‐coating material. The occurrence of EPS promotes the development of web and bridging structures binding the quartz grains and creating EPS‐coated surfaces. With increasing temperature, an amorphous mineral phase grows preferentially on these surfaces suggesting that EPS can act as a template for mineral nucleation. At temperatures >100°C, the order of crystallinity of the amorphous authigenic phase increases, transitioning to poorly‐ordered rosette‐like textures.
{"title":"Interdependence between bacterial EPS and early grain coat development","authors":"Dimitrios Charlaftis, S. Jones, Lars Grimm, A. Kappler","doi":"10.1111/ter.12648","DOIUrl":"https://doi.org/10.1111/ter.12648","url":null,"abstract":"Bacteria are the most abundant forms of life we know on our planet, able to survive in a variety of habitats, that play an important role in mineral formation and transformation processes. Here, we present laboratory experiments in which unconsolidated quartz grains were seeded with Geobacter sulfurreducens cells and exposed to a mineral medium solution for 96 hours at temperatures of between 60°C and 120°C. Experimental data show the interdependence between extracellular polymeric substances (EPS) and the early formation of grain‐coating material. The occurrence of EPS promotes the development of web and bridging structures binding the quartz grains and creating EPS‐coated surfaces. With increasing temperature, an amorphous mineral phase grows preferentially on these surfaces suggesting that EPS can act as a template for mineral nucleation. At temperatures >100°C, the order of crystallinity of the amorphous authigenic phase increases, transitioning to poorly‐ordered rosette‐like textures.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"241 - 249"},"PeriodicalIF":2.4,"publicationDate":"2023-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48639436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yan Zhang, Zhongliang Wu, F. Romanelli, F. Vaccari, A. Peresan, Jiawei Li, G. Panza
In the network‐based on‐site earthquake early warning system (EEWS), the ‘blind zone’, namely the zone where the issued warning arrives later than the destructive S and surface waves, is one of the challenges affecting its effectiveness. The ‘blind zone’ is determined by the interstation distance, or equivalently the density of seismic stations, of the network. In this paper, we suggest a practical approach according to which, when in a region a temporary increase of seismic hazard is declared, additional stations are deployed in such a way that the blind zone is temporarily reduced. In the procedure, the time‐dependent neo‐deterministic seismic hazard assessment (TD‐NDSHA) plays a vital role in the identification of the regions potentially exposed to high macroseismic intensities. As a showcase example, we consider the scenario of year 2014 at the Sichuan‐Yunnan border of southwest China. The TD‐NDSHA is based on the standard NDSHA procedure at regional scale (bedrock conditions), with the ‘controlling earthquakes’ defined on the basis of the Annual Consultation. We show that the ‘blind zone’ can be reduced in the identified areas of interest (e.g., MMI ≥ VI), by deploying a limited number of additional seismic stations. In the case where false alarms can be tolerated, significant reduction of the ‘blind zone’ can be implemented by moving from a network‐based EEWS to a single‐sensor‐based EEWS and skipping the process of location and magnitude‐determination/prediction procedures.
{"title":"Earthquake Early Warning System (EEWS) empowered by Time‐Dependent Neo‐Deterministic Seismic Hazard Assessment (TD‐NDSHA)","authors":"Yan Zhang, Zhongliang Wu, F. Romanelli, F. Vaccari, A. Peresan, Jiawei Li, G. Panza","doi":"10.1111/ter.12647","DOIUrl":"https://doi.org/10.1111/ter.12647","url":null,"abstract":"In the network‐based on‐site earthquake early warning system (EEWS), the ‘blind zone’, namely the zone where the issued warning arrives later than the destructive S and surface waves, is one of the challenges affecting its effectiveness. The ‘blind zone’ is determined by the interstation distance, or equivalently the density of seismic stations, of the network. In this paper, we suggest a practical approach according to which, when in a region a temporary increase of seismic hazard is declared, additional stations are deployed in such a way that the blind zone is temporarily reduced. In the procedure, the time‐dependent neo‐deterministic seismic hazard assessment (TD‐NDSHA) plays a vital role in the identification of the regions potentially exposed to high macroseismic intensities. As a showcase example, we consider the scenario of year 2014 at the Sichuan‐Yunnan border of southwest China. The TD‐NDSHA is based on the standard NDSHA procedure at regional scale (bedrock conditions), with the ‘controlling earthquakes’ defined on the basis of the Annual Consultation. We show that the ‘blind zone’ can be reduced in the identified areas of interest (e.g., MMI ≥ VI), by deploying a limited number of additional seismic stations. In the case where false alarms can be tolerated, significant reduction of the ‘blind zone’ can be implemented by moving from a network‐based EEWS to a single‐sensor‐based EEWS and skipping the process of location and magnitude‐determination/prediction procedures.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"230 - 239"},"PeriodicalIF":2.4,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42518017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Bakowsky, D. Schneider, B. Grasemann, K. Soukis
Folegandros island lies between the established SW‐directed West Cycladic and S‐directed Santorini detachment systems. Preserving shear‐sense indicators with opposing kinematics, the geodynamics and timing of kinematics are debated. Using white mica 40Ar/39Ar geochronology complemented by structural data, we report a new Miocene top‐to‐S detachment system, the Folegandros Detachment System (FDS), that is coupled with pure‐shear flattening and juxtaposes the Cycladic Blueschist Unit below Early Cretaceous to early Eocene low‐grade marble and quartzitic‐phyllitic sequences, topped by a metaflysch. Chronostratigraphic correlation and detrital zircon geochronology reveal the low‐grade rocks from the hanging wall of the FDS likely belong to the Pelagonian Zone. Middle Miocene zircon and apatite (U‐Th)/He cooling ages correspond to the latest stages of exhumation. Observations of opposing kinematics on Sikinos, Ios and now Folegandros reveal that ductile thinning played a more significant role in accommodating Miocene exhumation of high‐pressure rocks in the southern Cyclades than previously postulated.
{"title":"Miocene ductile thinning below the Folegandros Detachment System, Cyclades, Greece","authors":"C. Bakowsky, D. Schneider, B. Grasemann, K. Soukis","doi":"10.1111/ter.12646","DOIUrl":"https://doi.org/10.1111/ter.12646","url":null,"abstract":"Folegandros island lies between the established SW‐directed West Cycladic and S‐directed Santorini detachment systems. Preserving shear‐sense indicators with opposing kinematics, the geodynamics and timing of kinematics are debated. Using white mica 40Ar/39Ar geochronology complemented by structural data, we report a new Miocene top‐to‐S detachment system, the Folegandros Detachment System (FDS), that is coupled with pure‐shear flattening and juxtaposes the Cycladic Blueschist Unit below Early Cretaceous to early Eocene low‐grade marble and quartzitic‐phyllitic sequences, topped by a metaflysch. Chronostratigraphic correlation and detrital zircon geochronology reveal the low‐grade rocks from the hanging wall of the FDS likely belong to the Pelagonian Zone. Middle Miocene zircon and apatite (U‐Th)/He cooling ages correspond to the latest stages of exhumation. Observations of opposing kinematics on Sikinos, Ios and now Folegandros reveal that ductile thinning played a more significant role in accommodating Miocene exhumation of high‐pressure rocks in the southern Cyclades than previously postulated.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"220 - 229"},"PeriodicalIF":2.4,"publicationDate":"2023-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42982922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Almqvist, R. Lelij, K. Högdahl, R. Lescoutre, J. Schönenberger, H. Fossen, H. Sjöström, C. Juhlin, S. Luth, S. Grigull, G. Viola
This study presents K‐Ar ages of illite‐bearing fault gouges in crystalline basement in central‐western Sweden. Samples were taken from two faults that localized brittle deformation marginal to and within mafic dikes that intruded Paleoproterozoic granitoids. K‐Ar ages from 10 separated grain fractions span from 823 to 392 Ma. Older ages obtained (823–477 Ma) were influenced by a mixture of illite and K‐feldspar; the latter likely formed during a hydrothermal event prior to faulting. The remaining ages (442.1 ± 9.7 to 391.7 ± 6.1 Ma) were obtained from fractions from both faults hosting only authigenic illite and show that illite crystallized during the Scandian phase of the Caledonian orogeny. These results indicate that previously presumed autochthonous Caledonian basement was involved in continental contraction and subsequent collapse of the Caledonian orogen, influencing both the mode and depth of penetration of deformation into Baltica.
{"title":"Brittle basement deformation during the Caledonian Orogeny observed by K‐Ar geochronology of illite‐bearing fault gouge in west‐central Sweden","authors":"B. Almqvist, R. Lelij, K. Högdahl, R. Lescoutre, J. Schönenberger, H. Fossen, H. Sjöström, C. Juhlin, S. Luth, S. Grigull, G. Viola","doi":"10.1111/ter.12645","DOIUrl":"https://doi.org/10.1111/ter.12645","url":null,"abstract":"This study presents K‐Ar ages of illite‐bearing fault gouges in crystalline basement in central‐western Sweden. Samples were taken from two faults that localized brittle deformation marginal to and within mafic dikes that intruded Paleoproterozoic granitoids. K‐Ar ages from 10 separated grain fractions span from 823 to 392 Ma. Older ages obtained (823–477 Ma) were influenced by a mixture of illite and K‐feldspar; the latter likely formed during a hydrothermal event prior to faulting. The remaining ages (442.1 ± 9.7 to 391.7 ± 6.1 Ma) were obtained from fractions from both faults hosting only authigenic illite and show that illite crystallized during the Scandian phase of the Caledonian orogeny. These results indicate that previously presumed autochthonous Caledonian basement was involved in continental contraction and subsequent collapse of the Caledonian orogen, influencing both the mode and depth of penetration of deformation into Baltica.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"213 - 219"},"PeriodicalIF":2.4,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44874300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New detrital zircon age results from the Lusitanian Basin are integrated with published data for the Mesozoic of west Iberia and eastern Canada (4959 concordant ages). Zircons in new samples are either mainly Devonian‐Permian, Cryogenian‐Ediacaran or reveal a combination of these two age populations, showing secondary to minor Mesoproterozoic‐Archean ages. Statistical tools applied to the compiled age data allow grouping the samples according to age signatures and explain main features of the age spectra. Age signatures are determined by the abundance of zircon: (1) recycled from terranes involved in Pangea amalgamation; (2) associated with Acadian‐Variscan crystalline rocks (~420–310 Ma), which becomes younger from the Laurentian to the Gondwanan sides of the orogen; (3) associated with post‐collisional events (~300–285 Ma) that affected different terranes and were exhumed in major structures controlling basin formation; and (4) resulting from Mesozoic magmatism (~145 Ma) with a stronger imprint in the west Atlantic margin.
{"title":"Detrital zircon age signatures of the Mesozoic in the Lusitanian Basin and implications for the evolution of Iberia–Newfoundland conjugate margins","authors":"P. Dinis, P. Vermesch, P. Callapez","doi":"10.1111/ter.12644","DOIUrl":"https://doi.org/10.1111/ter.12644","url":null,"abstract":"New detrital zircon age results from the Lusitanian Basin are integrated with published data for the Mesozoic of west Iberia and eastern Canada (4959 concordant ages). Zircons in new samples are either mainly Devonian‐Permian, Cryogenian‐Ediacaran or reveal a combination of these two age populations, showing secondary to minor Mesoproterozoic‐Archean ages. Statistical tools applied to the compiled age data allow grouping the samples according to age signatures and explain main features of the age spectra. Age signatures are determined by the abundance of zircon: (1) recycled from terranes involved in Pangea amalgamation; (2) associated with Acadian‐Variscan crystalline rocks (~420–310 Ma), which becomes younger from the Laurentian to the Gondwanan sides of the orogen; (3) associated with post‐collisional events (~300–285 Ma) that affected different terranes and were exhumed in major structures controlling basin formation; and (4) resulting from Mesozoic magmatism (~145 Ma) with a stronger imprint in the west Atlantic margin.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"203 - 212"},"PeriodicalIF":2.4,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42212461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Proto‐Tethyan orogenic processes prior to the late Ordovician collision remain unclear. Both whole‐rock La/Yb‐ and zircon Eu/Eu*‐based crustal thickness proxies along with petrological and geological observations were used to reconstruct mountain‐building history for the West Kunlun orogenic belt, China, over the span of Early Palaeozoic. Here, we demonstrate that Proto‐Tethyan West Kunlun crust has observed significant accretionary orogeneses at 520–480 Ma and 480–450 Ma and collisional orogenesis at 450–400 Ma. The 520–480 Ma accretionary orogenesis in West Kunlun together with the coeval Delamerian accretionary contractional orogenesis in eastern Australia were simultaneously induced by continent‐continent collisions that welded the Gondwana landmass. Ca. 440 Ma docking of Tarim and its eastern neighbouring blocks along the northern margin of Gondwana in turn triggered the Lachlan accretionary orogenesis along the opposite margin. This study highlights that accretionary orogenesis could be a manifestation of far‐field compressional stress from continent‐continent collision.
{"title":"Accretionary orogenesis triggered by collision across continent distance: Evidence from the Proto‐Tethyan West Kunlun, China","authors":"Yan-Jun Wang, Weiguang Zhu, Zhenghong Zhang, Kang Yang, Chengquan Wu, Jinhong Xu, Chengbiao Leng, Jian‐Bing Xu","doi":"10.1111/ter.12643","DOIUrl":"https://doi.org/10.1111/ter.12643","url":null,"abstract":"Proto‐Tethyan orogenic processes prior to the late Ordovician collision remain unclear. Both whole‐rock La/Yb‐ and zircon Eu/Eu*‐based crustal thickness proxies along with petrological and geological observations were used to reconstruct mountain‐building history for the West Kunlun orogenic belt, China, over the span of Early Palaeozoic. Here, we demonstrate that Proto‐Tethyan West Kunlun crust has observed significant accretionary orogeneses at 520–480 Ma and 480–450 Ma and collisional orogenesis at 450–400 Ma. The 520–480 Ma accretionary orogenesis in West Kunlun together with the coeval Delamerian accretionary contractional orogenesis in eastern Australia were simultaneously induced by continent‐continent collisions that welded the Gondwana landmass. Ca. 440 Ma docking of Tarim and its eastern neighbouring blocks along the northern margin of Gondwana in turn triggered the Lachlan accretionary orogenesis along the opposite margin. This study highlights that accretionary orogenesis could be a manifestation of far‐field compressional stress from continent‐continent collision.","PeriodicalId":22260,"journal":{"name":"Terra Nova","volume":"35 1","pages":"193 - 202"},"PeriodicalIF":2.4,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44124169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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