J. R. Martínez Catalán, Karel Schulmann, P. Ayarza, J. Edel, M. Oreja
Arcuate traces of large structures characterize many mountain chains. The Variscan Belt is not an exception, and depicts one of the tightest oroclines in the Earth, the Ibero-Armorican Arc, as well as more open ones in the Eastern Moroccan Meseta, Central Iberia, French Massif Central and the Bohemian Massif. All Variscan arcs are considered true or secondary oroclines, and are late orogenic features, but their timing and deformation mechanisms differ. Models explaining their origin have been proposed for some individual arcs, and are generally controversial. This contribution aims at interpreting the ensemble of Variscan arcs highlighting their age relative to previous orogenic features as well as to those associated with arc development. Several mechanisms operated to form the arcs, the most important being ductile transcurrent shearing and rigid-plastic indentation, with shortening parallel to the orogen playing a secondary role. These mechanisms acted at different time intervals, their participation or relative importance differs for each arc and they gave rise to distinct associated structures. The development of the arcs is viewed as related to late Variscan dextral transpression provoked by displacement of Laurussia to the E relatively to Gondwana during the Serpukhovian to early Permian. Thematic collection: This article is part of the Processes of Pangea construction collection available at: https://www.lyellcollection.org/topic/collections/processes-of-pangea-construction
大型结构的弧形痕迹是许多山脉的特征。瓦里斯坎带也不例外，它描绘了地球上最紧密的弧线之一--伊比利亚-阿莫里卡弧线，以及位于摩洛哥东部梅塞塔、伊比利亚中部、法国中部山丘和波希米亚山丘的更为开阔的弧线。所有瓦里斯坎弧都被认为是真正的或次生的奥陶系，是晚期造山运动的特征，但它们的形成时间和变形机制各不相同。人们针对一些单独的弧提出了解释其起源的模型，但普遍存在争议。本文旨在解释瓦里坎弧的组合，强调它们相对于以前造山地貌的年龄，以及与弧的发展相关的年龄。形成弧的机制有多种，其中最重要的是韧性横流剪切和刚塑压痕，而与造山带平行的缩短则起次要作用。这些机制作用的时间间隔不同，对每个弧的参与程度或相对重要性也不同，并产生了不同的相关结构。这些弧的发展被认为与晚瓦里斯坎时期的右旋移位有关，该移位是由于在蛇绿岩至二叠纪早期，劳鲁西亚相对于冈瓦纳向东位移所引起的。 专题文集：本文是 "泛大陆构造过程"（Processes of Pangea construction）专题集的一部分，可登录 https://www.lyellcollection.org/topic/collections/processes-of-pangea-construction 查阅。
{"title":"Oroclinal arcs of the Variscan Belt: a consequence of transpression during the consolidation of Pangea","authors":"J. R. Martínez Catalán, Karel Schulmann, P. Ayarza, J. Edel, M. Oreja","doi":"10.1144/jgs2024-007","DOIUrl":"https://doi.org/10.1144/jgs2024-007","url":null,"abstract":"Arcuate traces of large structures characterize many mountain chains. The Variscan Belt is not an exception, and depicts one of the tightest oroclines in the Earth, the Ibero-Armorican Arc, as well as more open ones in the Eastern Moroccan Meseta, Central Iberia, French Massif Central and the Bohemian Massif. All Variscan arcs are considered true or secondary oroclines, and are late orogenic features, but their timing and deformation mechanisms differ. Models explaining their origin have been proposed for some individual arcs, and are generally controversial. This contribution aims at interpreting the ensemble of Variscan arcs highlighting their age relative to previous orogenic features as well as to those associated with arc development. Several mechanisms operated to form the arcs, the most important being ductile transcurrent shearing and rigid-plastic indentation, with shortening parallel to the orogen playing a secondary role. These mechanisms acted at different time intervals, their participation or relative importance differs for each arc and they gave rise to distinct associated structures. The development of the arcs is viewed as related to late Variscan dextral transpression provoked by displacement of Laurussia to the E relatively to Gondwana during the Serpukhovian to early Permian.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Processes of Pangea construction collection available at:\u0000 https://www.lyellcollection.org/topic/collections/processes-of-pangea-construction\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140974220","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}
The Tarim Craton (NW China) is a significant archive of tectonic events during the assembly and breakup of the Precambrian Supercontinents Columbia and Rodinia. It provides a comprehensive record of crustal development during the Proterozoic. In this paper, we review and synthesize the magmatic, metamorphic, and stratigraphic records of the Precambrian Tarim and delineate the geochronology of significant geological events that led to the formation of this major cratonic block. The extant geophysical and geological data show that the Tarim Craton consists mainly of the South and North Tarim blocks. The record of late Paleoproterozoic tectono-thermal events is well displayed in and across the craton, involving the amalgamation of these two blocks to form its unified crystalline basement during the Columbia buildup. However, the record of mid-Neoproterozoic events during the Rodinia assembly is only exposed around its periphery. The Proterozoic record of the craton includes the Mesoproterozoic–early Neoproterozoic low-grade metamorphic rock units and a late Neoproterozoic sedimentary cover. The early Mesoproterozoic stratigraphy in the SW, NE, and SE parts of the Tarim suggests a period of tectonic stability following the amalgamation of the North and South Tarim blocks in the late Paleoproterozoic, indicating the completion of its cratonic buildup. Supplementary material: https://doi.org/10.6084/m9.figshare.c.7225059
{"title":"Precambrian geological history of the Tarim Craton (NW China) involving the assembly and fragmentation of the Columbia and Rodinia supercontinents: review and synthesis","authors":"Duwei Qiu, Y. Dilek, Hongxiang Wu, Shaoying Huang, Dahai Sun, Caiming Luo, Yunjiang Duan, Wenfang Yuan, Hanlin Chen, Fengqi Zhang","doi":"10.1144/jgs2024-015","DOIUrl":"https://doi.org/10.1144/jgs2024-015","url":null,"abstract":"The Tarim Craton (NW China) is a significant archive of tectonic events during the assembly and breakup of the Precambrian Supercontinents Columbia and Rodinia. It provides a comprehensive record of crustal development during the Proterozoic. In this paper, we review and synthesize the magmatic, metamorphic, and stratigraphic records of the Precambrian Tarim and delineate the geochronology of significant geological events that led to the formation of this major cratonic block. The extant geophysical and geological data show that the Tarim Craton consists mainly of the South and North Tarim blocks. The record of late Paleoproterozoic tectono-thermal events is well displayed in and across the craton, involving the amalgamation of these two blocks to form its unified crystalline basement during the Columbia buildup. However, the record of mid-Neoproterozoic events during the Rodinia assembly is only exposed around its periphery. The Proterozoic record of the craton includes the Mesoproterozoic–early Neoproterozoic low-grade metamorphic rock units and a late Neoproterozoic sedimentary cover. The early Mesoproterozoic stratigraphy in the SW, NE, and SE parts of the Tarim suggests a period of tectonic stability following the amalgamation of the North and South Tarim blocks in the late Paleoproterozoic, indicating the completion of its cratonic buildup.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7225059\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140978609","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}
Qiming Zhao, Xiaofei Hu, Xiaoying Sun, Yanfei Pan, Baotian Pan
The Cenozoic uplift of the Qilian Shan is intimately connecting with the collision of India and Eurasian Plates, while the deformation mechanism is still a mystery for its far distance from the collision boundary. The first requirement for answering this question is to obtain the uplift process of this range, which remains debate. In this study, we compiled apatite fission track data from previous studies on the range, aims to reveal the spatial and temporal disparities or similarities for the exhumation process. Most age-evolution profiles and thermo-modeling results show a low exhumation rate during 80-20 Ma, corresponding to shorter track lengths, indicating a lower erosion rate and lower relief across the whole Qilian Shan region. The result also reveals two stages of rapid exhumation, during Cretaceous (120-80 Ma) and since Miocene (20-0 Ma). The exhumation history of the Qilian has no significant spatial difference, and the outward growth was limited at the southern and northern edge after 5 Ma. This temporal and spatial pattern for the exhumation of the Qilian Shan suggests that there was probably no obvious uplift at the initial collision of India-Tibet plates, and support the proposal that the whole Qilian range uplifted synchronously since 20 Ma. Thematic collection: This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at: https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change Supplementary material: https://doi.org/10.6084/m9.figshare.c.7224863
{"title":"Landform evolution of the Qilian Shan since 120 Ma revealed by Apatite fission track data","authors":"Qiming Zhao, Xiaofei Hu, Xiaoying Sun, Yanfei Pan, Baotian Pan","doi":"10.1144/jgs2023-193","DOIUrl":"https://doi.org/10.1144/jgs2023-193","url":null,"abstract":"The Cenozoic uplift of the Qilian Shan is intimately connecting with the collision of India and Eurasian Plates, while the deformation mechanism is still a mystery for its far distance from the collision boundary. The first requirement for answering this question is to obtain the uplift process of this range, which remains debate. In this study, we compiled apatite fission track data from previous studies on the range, aims to reveal the spatial and temporal disparities or similarities for the exhumation process. Most age-evolution profiles and thermo-modeling results show a low exhumation rate during 80-20 Ma, corresponding to shorter track lengths, indicating a lower erosion rate and lower relief across the whole Qilian Shan region. The result also reveals two stages of rapid exhumation, during Cretaceous (120-80 Ma) and since Miocene (20-0 Ma). The exhumation history of the Qilian has no significant spatial difference, and the outward growth was limited at the southern and northern edge after 5 Ma. This temporal and spatial pattern for the exhumation of the Qilian Shan suggests that there was probably no obvious uplift at the initial collision of India-Tibet plates, and support the proposal that the whole Qilian range uplifted synchronously since 20 Ma.\u0000 \u0000 Thematic collection:\u0000 This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at:\u0000 https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7224863\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140978958","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. Hawkesworth, Peter A. Cawood, B. Dhuime, Tony Kemp
The Earth is the only known planet where plate tectonics operates. We review features of Archaean and early Proterozoic geology that constrain tectonic environments and inform discussions of the onset of plate tectonics. There is the question of scale, and how the results of individual case studies are put into a wider global context. Global models may be difficult to test, and we seek to integrate evidence for plate tectonics being active with ancient records of subduction. We explore evidence for when the continental crust became rigid enough to facilitate plate tectonics, based on the occurrence of widespread dyke swarms and large sedimentary basins, relatively widespread granulite facies metamorphism, and evidence for crustal thickening. We argue that it remains difficult to constrain tectonic settings from contemporaneous metamorphic events without spatial control. Archaean cratons stabilised at different times in different areas from 3.1–2.5 Ga, juvenile continental crust changed from mafic to more intermediate compositions, there was a reduction in crustal growth at ca. 3 Ga, and increasing evidence for lateral movement of crustal fragments. These with the other changes at the end of the Archaean are taken to reflect the onset of plate tectonics as the dominant global regime.
地球是已知的唯一一个板块构造作用的星球。我们回顾了太古宙和新生代早期地质学的特征，这些特征制约着构造环境，并为关于板块构造开始的讨论提供信息。还有一个规模问题，即如何将个别案例研究的结果置于更广泛的全球背景下。全球模型可能难以检验，我们试图将板块构造活跃的证据与古代俯冲记录结合起来。我们根据广泛出现的堤坝群和大型沉积盆地、相对广泛的花岗岩变质作用以及地壳增厚的证据，探讨了大陆地壳何时变得足够坚硬以促进板块构造的证据。我们认为，在没有空间控制的情况下，仍然很难从同期变质事件中确定构造环境。在3.1-2.5 Ga期间，不同地区的太古宙陨石坑在不同时期趋于稳定，幼年大陆地壳从岩浆岩转变为更多的中间成分，地壳增厚在约3 Ga时有所减少，横向地壳增厚的证据不断增加。在大约 3 Ga 时，地壳增长速度减慢，有越来越多的证据表明地壳碎片发生了横向移动。这些变化以及太古宙末期的其他变化被认为反映了板块构造开始成为全球的主导机制。
{"title":"Tectonic processes and the evolution of the continental crust","authors":"C. Hawkesworth, Peter A. Cawood, B. Dhuime, Tony Kemp","doi":"10.1144/jgs2024-027","DOIUrl":"https://doi.org/10.1144/jgs2024-027","url":null,"abstract":"The Earth is the only known planet where plate tectonics operates. We review features of Archaean and early Proterozoic geology that constrain tectonic environments and inform discussions of the onset of plate tectonics. There is the question of scale, and how the results of individual case studies are put into a wider global context. Global models may be difficult to test, and we seek to integrate evidence for plate tectonics being active with ancient records of subduction. We explore evidence for when the continental crust became rigid enough to facilitate plate tectonics, based on the occurrence of widespread dyke swarms and large sedimentary basins, relatively widespread granulite facies metamorphism, and evidence for crustal thickening. We argue that it remains difficult to constrain tectonic settings from contemporaneous metamorphic events without spatial control. Archaean cratons stabilised at different times in different areas from 3.1–2.5 Ga, juvenile continental crust changed from mafic to more intermediate compositions, there was a reduction in crustal growth at ca. 3 Ga, and increasing evidence for lateral movement of crustal fragments. These with the other changes at the end of the Archaean are taken to reflect the onset of plate tectonics as the dominant global regime.","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140996326","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}
Discoidal carbonaceous compressions are the most common type of Precambrian macrofossils with a long temporal range starting from the late Paleoproterozoic. However, their unsolved biological nature restricts our understanding of the early evolution of macroscopic life. Here we report an assemblage of well-preserved discoidal carbonaceous macrofossils from the early Mesoproterozoic Gaoyuzhuang Formation in North China, which provides insights into this problem. They are preserved in round to elliptical shapes with sizes ranging from millimeters to several centimeters. Petrographic thin sections show that the macrofossils consist of laminated structures with alternating organic matter along with clay minerals and dolomites. Neither cellular structures nor individual microfossils were identified within them, but their regular shape, internal structures, and associated mineral constituents suggest that they are probably remains of the microbial biofilms, rather than multicellular organisms. It presents a well-preserved fossil example of microbial biofilms with macroscopic size and regular overall morphology. It further implies a possible origin of microbial biofilm for some of the early carbonaceous macrofossils and calls for detailed reexaminations of those macrofossils to exclude such possibilities. Our finding is consistent with previous studies that biofilms may have played an important role in survival for early microorganisms in the Precambrian ecosystem. Thematic collection: This article is part of the The North China Craton as a window to Earth’s middle age collection available at: https://www.lyellcollection.org/topic/collections/the-north-china-craton-as-a-window-to-earths-middle-age
{"title":"Discoidal carbonaceous compressions from the Early Mesoproterozoic Gaoyuzhuang Formation: a fossil example of microbial biofilm","authors":"Kai Chen, Lanyun Miao, Fangchen Zhao, Maoyan Zhu","doi":"10.1144/jgs2024-005","DOIUrl":"https://doi.org/10.1144/jgs2024-005","url":null,"abstract":"Discoidal carbonaceous compressions are the most common type of Precambrian macrofossils with a long temporal range starting from the late Paleoproterozoic. However, their unsolved biological nature restricts our understanding of the early evolution of macroscopic life. Here we report an assemblage of well-preserved discoidal carbonaceous macrofossils from the early Mesoproterozoic Gaoyuzhuang Formation in North China, which provides insights into this problem. They are preserved in round to elliptical shapes with sizes ranging from millimeters to several centimeters. Petrographic thin sections show that the macrofossils consist of laminated structures with alternating organic matter along with clay minerals and dolomites. Neither cellular structures nor individual microfossils were identified within them, but their regular shape, internal structures, and associated mineral constituents suggest that they are probably remains of the microbial biofilms, rather than multicellular organisms. It presents a well-preserved fossil example of microbial biofilms with macroscopic size and regular overall morphology. It further implies a possible origin of microbial biofilm for some of the early carbonaceous macrofossils and calls for detailed reexaminations of those macrofossils to exclude such possibilities. Our finding is consistent with previous studies that biofilms may have played an important role in survival for early microorganisms in the Precambrian ecosystem.\u0000 \u0000 Thematic collection:\u0000 This article is part of the The North China Craton as a window to Earth’s middle age collection available at:\u0000 https://www.lyellcollection.org/topic/collections/the-north-china-craton-as-a-window-to-earths-middle-age\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140995397","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}
Rocky shorelines form where basement highs are eroded and flooded during marine transgressive events. Despite the Mesozoic North Sea rift generated numerous platform margins and rotated fault blocks which acted as basement highs, rocky shoreline deposits have not been previously reported. In the rock record rocky shoreline deposits are usually represented by thin conglomerates overlying major unconformities, and are typically characterised by their ichnological aspects, rather than their depositional facies. This study uses the sedimentological aspects of modern and Miocene rocky shorelines from Spain and Austria, to create facies models which are then applied to the recognition of rocky shorelines in the Mesozoic of the Central North Sea. Our results demonstrate that structureless, clast-supported, poorly-to-moderately sorted conglomerate-breccia deposits are associated with competent basement lithologies, which produce hard, resistant coastal cliffs around previously overlooked volcanic centres in the subsurface of the North Sea. The basement lithologies in most of the Central North Sea favoured the formation of softer coastal cliffs, with less resistant lithologies that did not generate or preserve gravel size particles, being mostly characterised by low-angle, unconformity-bounded sandstone and fine-grained deposits and precluding the preservation and recognition of Mesozoic rocky shores in much of the North Sea's stratigraphic record.
{"title":"Facies models for rocky shorelines and their application to transgressed basement highs in the North Sea","authors":"Josep M. Puig López, J. Howell","doi":"10.1144/jgs2024-012","DOIUrl":"https://doi.org/10.1144/jgs2024-012","url":null,"abstract":"Rocky shorelines form where basement highs are eroded and flooded during marine transgressive events. Despite the Mesozoic North Sea rift generated numerous platform margins and rotated fault blocks which acted as basement highs, rocky shoreline deposits have not been previously reported. In the rock record rocky shoreline deposits are usually represented by thin conglomerates overlying major unconformities, and are typically characterised by their ichnological aspects, rather than their depositional facies. This study uses the sedimentological aspects of modern and Miocene rocky shorelines from Spain and Austria, to create facies models which are then applied to the recognition of rocky shorelines in the Mesozoic of the Central North Sea. Our results demonstrate that structureless, clast-supported, poorly-to-moderately sorted conglomerate-breccia deposits are associated with competent basement lithologies, which produce hard, resistant coastal cliffs around previously overlooked volcanic centres in the subsurface of the North Sea. The basement lithologies in most of the Central North Sea favoured the formation of softer coastal cliffs, with less resistant lithologies that did not generate or preserve gravel size particles, being mostly characterised by low-angle, unconformity-bounded sandstone and fine-grained deposits and precluding the preservation and recognition of Mesozoic rocky shores in much of the North Sea's stratigraphic record.","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141019501","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}
Qiang Su, Xianyan Wang, Linman Gao, S. Yi, Zhiyong Han, Junjie Ren, Jef Vandenberghe, Huayu Lu, Ronald Van Balen
Fluvial terraces are important archives for inferring changes in river dynamics. In the northeastern Tibetan Plateau (NETP), the Huangshui River flows through broad depressions and narrow gorges. This morphology is the result of strike-slip- and reverse-faulting. The differential vertical motions cause the formation of diverse fluvial terraces. Morphological analyses, sedimentary successions, and optically stimulated luminescence (OSL) dating are used to map, characterize, and date fluvial terraces in two depressions and the connecting gorge. Our results show that an important phase of tectonism occurred shortly after 138 ka, because: (1) Terraces older than 138 ka in the gorge show clear deformation in their longitudinal profiles; (2) Terraces from the last interglacial are composed of a thick fill terrace in the upstream depression, a strath terrace in the gorge, and a fill terrace created by an alluvial fan in the downstream depression; (3) The aggradation of the last interglacial terrace began synchronously in the upstream and downstream depression, while the abandonment age becomes younger in an upstream direction (from c. 131 ka to c. 91 ka). The transient abandonment reflects an upstream migrating knickpoint. Thematic collection: This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at: https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change
冲积阶地是推断河流动态变化的重要档案。在青藏高原东北部（NETP），湟水河流经宽阔的洼地和狭窄的峡谷。这种形态是走向滑动和逆断层作用的结果。不同的垂直运动形成了多种多样的河流阶地。我们利用形态学分析、沉积演替和光学激发发光（OSL）测年方法，对两个洼地和连接峡谷的河流阶地进行了测绘、定性和测年。我们的研究结果表明，138 ka 之后不久发生了一个重要的构造运动阶段，因为(1) 峡谷中年龄大于 138 ka 的阶地在其纵向剖面上显示出明显的变形；(2) 最后一个间冰期的阶地由上游洼地中的厚填充阶地、峡谷中的地层阶地和下游洼地中冲积扇形成的填充阶地组成；(3) 最后一个间冰期的阶地在上游和下游洼地中同步开始增生，而在上游方向的废弃年龄变得更小（从约 131 ka 到约 91 ka）。131 ka 到约 91 ka）。瞬时废弃反映了上游迁移的节理点。 专题文集：本文是中生代和新生代构造、地貌和气候变化文集的一部分，可在以下网址查阅： https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change
{"title":"The impact of faulting-induced uplift and subsidence on terrace formation and abandonment: A case study of the Huangshui River, NE Tibetan Plateau","authors":"Qiang Su, Xianyan Wang, Linman Gao, S. Yi, Zhiyong Han, Junjie Ren, Jef Vandenberghe, Huayu Lu, Ronald Van Balen","doi":"10.1144/jgs2023-104","DOIUrl":"https://doi.org/10.1144/jgs2023-104","url":null,"abstract":"\u0000 Fluvial terraces are important archives for inferring changes in river dynamics. In the northeastern Tibetan Plateau (NETP), the Huangshui River flows through broad depressions and narrow gorges. This morphology is the result of strike-slip- and reverse-faulting. The differential vertical motions cause the formation of diverse fluvial terraces. Morphological analyses, sedimentary successions, and optically stimulated luminescence (OSL) dating are used to map, characterize, and date fluvial terraces in two depressions and the connecting gorge. Our results show that an important phase of tectonism occurred shortly after 138 ka, because: (1) Terraces older than 138 ka in the gorge show clear deformation in their longitudinal profiles; (2) Terraces from the last interglacial are composed of a thick fill terrace in the upstream depression, a strath terrace in the gorge, and a fill terrace created by an alluvial fan in the downstream depression; (3) The aggradation of the last interglacial terrace began synchronously in the upstream and downstream depression, while the abandonment age becomes younger in an upstream direction (from\u0000 c.\u0000 131 ka to\u0000 c.\u0000 91 ka). The transient abandonment reflects an upstream migrating knickpoint.\u0000 \u0000 \u0000 Thematic collection:\u0000 This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at:\u0000 https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140234000","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}
The structures, sedimentary fill, and magmatic rocks of sedimentary basins are the products of regional tectonic evolution and are crucial to studying the basin's tectonic-paleogeographic environment and regional tectonic evolution. The present study discussed the zircon U-Pb dating of volcanic rocks samples, in-situ Hf isotope, and whole rock geochemistry analysis of the Bayingobi basin, the paleogeographic, sedimentary filling, and tectonic background of the Bayinggobi basin through the outcrop and core description of Meso-Cenozoic strata, stratigraphic correlation and lithofacies analysis. The U-Pb age of the volcanic rocks is 132–102 Ma, and the in-situ Hf isotopic values range from -20.99 to +29.48. The 87 Sr/ 86 Sr and 143 Nd/ 144 Nd isotopic ratios of the volcanic rocks are 0.707049–0.879761 and 0.511846–0.512540, respectively, and the Nd isotopic values range from -0.62 to -6.83. The volcanic rocks in the basin have the characteristics of congenital margin island arc volcanic rocks (CAA) with loss of Nb, Ta, and enrichment of Pb, originating mainly from dehydration melting of the plate subduction. The lower Cretaceous Bayingobi, Suhongtu, and Yingen Formations developed specifically delta-lacustrine deposits. The lower and upper member of the Bayinggobi Formation was deposited at Berriasian to Valanginian and Valanginian to late Aptian, respectively. The Suhongtu Formation was deposited during the late Aptian to early Albian and controlled by the strike of Engeer Us fault. The Yingen Formation was deposited in the late faulted depression stage at late Albian. Because of the subduction of the Mongol-Okhotsk Ocean plate in the Early Cretaceous, several depressions (sags) were formed in the Bayingobi basin, accompanied by the eruption of continental plate margin island arc magmas. With the closure of the Mongol-Okhotsk Ocean in the late early Cretaceous, the basin uplifted as a whole and the Upper Cretaceous Ulansuhai Formation was deposited. Supplementary material: https://doi.org/10.6084/m9.figshare.c.7105807
{"title":"Mesozoic-Cenozoic tectonic-paleogeographic evolution of Bayingobi basin: response to subduction and collision of the Mongol-Okhotsk Ocean plate","authors":"Liu Bo, Peng Hao, Peng Li, Haiyun Zhang, Xujie Guo, Pengfei Zhang, Yanwei Qin","doi":"10.1144/jgs2023-109","DOIUrl":"https://doi.org/10.1144/jgs2023-109","url":null,"abstract":"\u0000 The structures, sedimentary fill, and magmatic rocks of sedimentary basins are the products of regional tectonic evolution and are crucial to studying the basin's tectonic-paleogeographic environment and regional tectonic evolution. The present study discussed the zircon U-Pb dating of volcanic rocks samples, in-situ Hf isotope, and whole rock geochemistry analysis of the Bayingobi basin, the paleogeographic, sedimentary filling, and tectonic background of the Bayinggobi basin through the outcrop and core description of Meso-Cenozoic strata, stratigraphic correlation and lithofacies analysis. The U-Pb age of the volcanic rocks is 132–102 Ma, and the in-situ Hf isotopic values range from -20.99 to +29.48. The\u0000 87\u0000 Sr/\u0000 86\u0000 Sr and\u0000 143\u0000 Nd/\u0000 144\u0000 Nd isotopic ratios of the volcanic rocks are 0.707049–0.879761 and 0.511846–0.512540, respectively, and the Nd isotopic values range from -0.62 to -6.83. The volcanic rocks in the basin have the characteristics of congenital margin island arc volcanic rocks (CAA) with loss of Nb, Ta, and enrichment of Pb, originating mainly from dehydration melting of the plate subduction. The lower Cretaceous Bayingobi, Suhongtu, and Yingen Formations developed specifically delta-lacustrine deposits. The lower and upper member of the Bayinggobi Formation was deposited at Berriasian to Valanginian and Valanginian to late Aptian, respectively. The Suhongtu Formation was deposited during the late Aptian to early Albian and controlled by the strike of Engeer Us fault. The Yingen Formation was deposited in the late faulted depression stage at late Albian. Because of the subduction of the Mongol-Okhotsk Ocean plate in the Early Cretaceous, several depressions (sags) were formed in the Bayingobi basin, accompanied by the eruption of continental plate margin island arc magmas. With the closure of the Mongol-Okhotsk Ocean in the late early Cretaceous, the basin uplifted as a whole and the Upper Cretaceous Ulansuhai Formation was deposited.\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7105807\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140248352","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}
Jerzy Nawrocki, M. Pańczyk, T. Malata, Piotr S. Dziadzio, Leszek Balicki, Paweł Derkowski
A set of 6368 U-Pb isotope ages of detrital zircons from 53 samples of the Oligocene to Early Miocene Menilite and Krosno formations (Outer Western Carpathians) was obtained and interpreted in terms of their sources. In both units the most frequent are mid-Variscan and Cadomian zircons that were derived from the Variscan Internides underlying the studied basin, and from the Brunovistulia Terrane, respectively. The coincidence of detrital zircon ages and clast ages indicates that zircons of that age can be at least partly of first cycle. Sveconorwegian and Calymmian – Statherian recycled zircons of Baltica origin, highly frequent in the Menilite Formation, are most probably sourced from Lower Devonian sediments of the Małopolska Massif. The Oligocene basin of Menilite Formation was supplied in detrital material largely from the north where Meta-Carpathian Swell was elevated in the area of Małopolska Massif and Brunovistulia Terrane. During sedimentation of the Krosno Formation this source expired. A considerable input to the Menilite Formation of Baltica derived zircons and a limited number of zircons from sources located SE of the study area suggests that they were deposited in a relatively shallow and isolated basin. Supplementary material: https://doi.org/10.6084/m9.figshare.c.7100071
{"title":"Insight into Oligocene – Early Miocene palaeogeography of the Carpathians in Poland: first cycle and recycled detrital zircon provenance in the Menilite and Krosno formations","authors":"Jerzy Nawrocki, M. Pańczyk, T. Malata, Piotr S. Dziadzio, Leszek Balicki, Paweł Derkowski","doi":"10.1144/jgs2023-124","DOIUrl":"https://doi.org/10.1144/jgs2023-124","url":null,"abstract":"A set of 6368 U-Pb isotope ages of detrital zircons from 53 samples of the Oligocene to Early Miocene Menilite and Krosno formations (Outer Western Carpathians) was obtained and interpreted in terms of their sources. In both units the most frequent are mid-Variscan and Cadomian zircons that were derived from the Variscan Internides underlying the studied basin, and from the Brunovistulia Terrane, respectively. The coincidence of detrital zircon ages and clast ages indicates that zircons of that age can be at least partly of first cycle. Sveconorwegian and Calymmian – Statherian recycled zircons of Baltica origin, highly frequent in the Menilite Formation, are most probably sourced from Lower Devonian sediments of the Małopolska Massif. The Oligocene basin of Menilite Formation was supplied in detrital material largely from the north where Meta-Carpathian Swell was elevated in the area of Małopolska Massif and Brunovistulia Terrane. During sedimentation of the Krosno Formation this source expired. A considerable input to the Menilite Formation of Baltica derived zircons and a limited number of zircons from sources located SE of the study area suggests that they were deposited in a relatively shallow and isolated basin.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7100071\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264915","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}
Mauricio González Guillot, P. T. Torres Carbonell, Sebastián J. Cao, Constanza Lobo, S. Bordese, M. H. Hollanda
We report the field geology, petrography, geochemistry and geochronology data for two dyke swarms in the Fuegian Andes, with the aim of correlating them with known suites and of improving the knowledge on the magmatism of the Late Cretaceous rear-arc and its relation with ductile deformation. We also provide keys for correlation based on amphibole K 2 O content. The Trapecio dyke swarm is mildly alkaline and ferriferous, with a zircon U-Pb age of 75 Ma; thus it belongs to the Fuegian Potassic Magmatism (78-68 Ma). The Ushuaia Peninsula dyke swarm, also known as Ushuaia Peninsula Andesites (UPA), was shown to be high-K calc-alkaline and magnesian. New radiometric ages gave 87-86 Ma. While the UPA dyke swarm exhibits foliation associated with ductile deformation, the Trapecio dyke swarm is post-kinematic and reveals emplacement controlled by the slaty cleavage in the metapelite host. Field and geophysical evidence suggest both swarms overlie small upper-crustal plutons, mostly buried. The variable composition of dykes suggests a protracted history of dyke injection, mostly fed from deeper reservoirs. Contact metamorphism around both pluton-dyke systems is very weak. By comparison with adjacent plutons we argue that the main variables controlling aureole development are small magma volumes and low injection rates. Supplementary material : https://doi.org/10.6084/m9.figshare.c.7097733
我们报告了富埃吉安第斯山脉两个堤坝群的野外地质学、岩相学、地球化学和地质年代学数据，目的是将它们与已知的岩浆群关联起来，并增进对晚白垩世后弧岩浆活动及其与韧性变形关系的了解。我们还提供了基于闪石 K 2 O 含量的关联关键。特拉佩西奥堤坝群呈弱碱性，含铁质，锆石U-Pb年龄为75Ma，因此属于富吉安钾长岩岩浆活动（78-68Ma）。乌斯怀亚半岛堤坝群（又称乌斯怀亚半岛安山岩（UPA））被证明是高K钙碱性和镁质岩。新的放射性年龄为 87-86 Ma。乌斯怀亚半岛安山岩（UPA）堤群表现出与韧性变形有关的褶皱，而特拉佩西奥堤群则是后运动性的，显示出受玄武岩主岩中的板条裂隙控制的成岩过程。野外和地球物理证据表明，这两个岩群都位于小型上壳岩体之上，大部分被掩埋。堤坝的成分多变，表明堤坝注入历史悠久，大部分来自较深的储层。两个岩浆岩-堤坝系统周围的接触变质作用都非常弱。通过与邻近的岩浆岩进行比较，我们认为控制岩浆柱发育的主要变量是岩浆体积小和注入率低。 补充材料：https://doi.org/10.6084/m9.figshare.c.7097733
{"title":"Field geology, petrology and geochronology of pluton-dyke systems, the Trapecio and Ushuaia Peninsula dyke swarms (Fuegian Andes): emplacement conditions and relation with tectonics","authors":"Mauricio González Guillot, P. T. Torres Carbonell, Sebastián J. Cao, Constanza Lobo, S. Bordese, M. H. Hollanda","doi":"10.1144/jgs2023-094","DOIUrl":"https://doi.org/10.1144/jgs2023-094","url":null,"abstract":"\u0000 We report the field geology, petrography, geochemistry and geochronology data for two dyke swarms in the Fuegian Andes, with the aim of correlating them with known suites and of improving the knowledge on the magmatism of the Late Cretaceous rear-arc and its relation with ductile deformation. We also provide keys for correlation based on amphibole K\u0000 2\u0000 O content. The Trapecio dyke swarm is mildly alkaline and ferriferous, with a zircon U-Pb age of 75 Ma; thus it belongs to the Fuegian Potassic Magmatism (78-68 Ma). The Ushuaia Peninsula dyke swarm, also known as Ushuaia Peninsula Andesites (UPA), was shown to be high-K calc-alkaline and magnesian. New radiometric ages gave 87-86 Ma. While the UPA dyke swarm exhibits foliation associated with ductile deformation, the Trapecio dyke swarm is post-kinematic and reveals emplacement controlled by the slaty cleavage in the metapelite host. Field and geophysical evidence suggest both swarms overlie small upper-crustal plutons, mostly buried. The variable composition of dykes suggests a protracted history of dyke injection, mostly fed from deeper reservoirs. Contact metamorphism around both pluton-dyke systems is very weak. By comparison with adjacent plutons we argue that the main variables controlling aureole development are small magma volumes and low injection rates.\u0000 \u0000 \u0000 Supplementary material\u0000 :\u0000 https://doi.org/10.6084/m9.figshare.c.7097733\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140079732","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：