According to an analysis of the geological features in the eastern sector of the Bangong Co-Nujiang River suture zone, the Tethyan evolution can be divided into three stages. (1) The Embryo-Tethyan stage (Pz1): An imm...According to an analysis of the geological features in the eastern sector of the Bangong Co-Nujiang River suture zone, the Tethyan evolution can be divided into three stages. (1) The Embryo-Tethyan stage (Pz1): An immature volcanic arc developed in Taniantaweng (Tanen Taunggyi) Range, indicating the existence of an Embryo-Tethyan ocean. (2) The Palaeo-Tethyan stage (C-T2: During the Carboniferous the northern side of the Taniantaweng Range was the main domain of the Palaeo-Tethyan ocean, in which developed flysch sediments intercalated with bimodal volcanic rocks and oceanic tholeiite, and Pemian-Early Triassic are granites were superimposed on the Taniantaweng magmatic are; on the southern side the Dêngqên-Nujiang zone started secondary extension during the Carboniferous, in which the Nujiang ophiolite developed, and the Palaeo-Tethyan ocean closed before the Middle Triassic. (3) The Neo-Tethyan stage (T3-E): During the Late Triassic the Dêngqên zone developed into a relatively matural ocean basin, in which the Dêngqên ophiolite was formed. By the end of the Triassic intraocean subduction occurred, and the ocean domain was reduced gradually, and collided and closed by the end of the Early Jurassic, forming the Yazong mélange; then the Tethyan ocean was completely closed.展开更多
A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they...A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they belong to the;32 Ma Comei LIP（Zhu et al.,2009）or展开更多
The Jurassic–Cretaceous ophiolites in the Alpine–Himalayan orogenic belt represent fragments of oceanic lithosphere,developed in different seaways separated by Gondwana–derived ribbon continents within a broad
The Nan Suture and Sukhothai Arc Terrane are products of the eastward subduction of the Paleotethyan Ocean during the Late Carboniferous to Triassic.However,their footprints in northwestern Laos are poorly constrained...The Nan Suture and Sukhothai Arc Terrane are products of the eastward subduction of the Paleotethyan Ocean during the Late Carboniferous to Triassic.However,their footprints in northwestern Laos are poorly constrained.New geochronological and geochemical data presented in this study demonstrate a Late Permian origin for the andesitic rocks in the B.Xiengnou area rather than Late Triassic.The breccia-bearing andesitic tuff in the B.On ultramafic complex yield a zircon U-Pb age of 260±1.4 Ma,geochemically displaying a MORB-like signature.The andesitic tuff in the B.Kiophoulan-B.Houayhak belt gave the U-Pb age of 254±1.3 Ma,with arc-like geochemical affinity.By combining geochronological and geochemical data from the Nan Suture and Sukhothai Arc Terrane,the authors suggest that the andesitic rocks in the B.On ultramafic complex formed in a back-arc basin background,which connected the Jinghong and Nan back-arc basin during the Permian;while the andesitic tuff in the B.Kiophoulan-B.Houayhak belt erupted in the Sukhothai continental arc setting.展开更多
The Tethyan evolution depicts the continuous process of landmasses separating from the Gondwana continent in the south,drifting northwards,and subsequently colliding with the continents in the north over the past 500 ...The Tethyan evolution depicts the continuous process of landmasses separating from the Gondwana continent in the south,drifting northwards,and subsequently colliding with the continents in the north over the past 500 million years.In this process,the Tethyan oceans that formed between the landmass and the southern or northern continents underwent growth,evolution,and eventual closure with the early Cenozoic India-Eurasia collision.However,the Tethyan lithosphere did not disappear but rather continued to evolve after entering into the deep Earth.The current position,morphology,and volume of the subducted Tethyan oceanic slabs in the deep mantle record the latest moment of this continuous evolution,providing critical constraints for Tethyan studies.This paper summarizes and analyzes the results of global-scale whole-mantle seismic tomography in the past nearly two decades,revealing a northwest-southeast seismically high-velocity anomaly,which is linearly distributed at depths of 1000–2000 km beneath the Tethyan realm and referred to as the Tethyan anomaly.By searching for an optimal linear combination of previous global seismic tomographic models to best match the known subducted slabs in the upper mantle,we observe that the Tethyan anomaly extends approximately 8700 km in length and 2600 km in width,exhibiting a parallel structure with northern and southern branches.Combining geological records of oceanic subduction initiation and previous geodynamic studies,this study suggests that the main body of the Tethyan anomaly represents the remnants of the subducted Neo-Tethyan oceanic slabs,which subducted from the Late Jurassic to the early Cenozoic.The northern branch consists of subducted slabs from the Neo-Tethys beneath the southern margin of Eurasia,while the southern branch likely reflects the intra-oceanic subducted slabs of Neo-Tethys during the Cretaceous.The western portion of the Tethyan anomaly may reflect remnants of Paleo-Tethys,while the eastern portion,towards India and the Bay of Bengal,shows signs of subduction towards the core-mantle boundary.Finally,this study discusses the future prospects of whole-mantle seismic tomographic studies focusing on the Tethyan realm.展开更多
文摘According to an analysis of the geological features in the eastern sector of the Bangong Co-Nujiang River suture zone, the Tethyan evolution can be divided into three stages. (1) The Embryo-Tethyan stage (Pz1): An immature volcanic arc developed in Taniantaweng (Tanen Taunggyi) Range, indicating the existence of an Embryo-Tethyan ocean. (2) The Palaeo-Tethyan stage (C-T2: During the Carboniferous the northern side of the Taniantaweng Range was the main domain of the Palaeo-Tethyan ocean, in which developed flysch sediments intercalated with bimodal volcanic rocks and oceanic tholeiite, and Pemian-Early Triassic are granites were superimposed on the Taniantaweng magmatic are; on the southern side the Dêngqên-Nujiang zone started secondary extension during the Carboniferous, in which the Nujiang ophiolite developed, and the Palaeo-Tethyan ocean closed before the Middle Triassic. (3) The Neo-Tethyan stage (T3-E): During the Late Triassic the Dêngqên zone developed into a relatively matural ocean basin, in which the Dêngqên ophiolite was formed. By the end of the Triassic intraocean subduction occurred, and the ocean domain was reduced gradually, and collided and closed by the end of the Early Jurassic, forming the Yazong mélange; then the Tethyan ocean was completely closed.
基金supported by National Science Foundation of China (Grant No. 41425010 & 41503023)China Geological Survey (Grant No. 12120114022701 & 12120115027101)
文摘A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they belong to the;32 Ma Comei LIP（Zhu et al.,2009）or
文摘The Jurassic–Cretaceous ophiolites in the Alpine–Himalayan orogenic belt represent fragments of oceanic lithosphere,developed in different seaways separated by Gondwana–derived ribbon continents within a broad
基金This study is co-supported by the National Natural Science Foundation of China(41702087)the China Geological Survey(DD2019444)the China Scholarship Council(201908575026).
文摘The Nan Suture and Sukhothai Arc Terrane are products of the eastward subduction of the Paleotethyan Ocean during the Late Carboniferous to Triassic.However,their footprints in northwestern Laos are poorly constrained.New geochronological and geochemical data presented in this study demonstrate a Late Permian origin for the andesitic rocks in the B.Xiengnou area rather than Late Triassic.The breccia-bearing andesitic tuff in the B.On ultramafic complex yield a zircon U-Pb age of 260±1.4 Ma,geochemically displaying a MORB-like signature.The andesitic tuff in the B.Kiophoulan-B.Houayhak belt gave the U-Pb age of 254±1.3 Ma,with arc-like geochemical affinity.By combining geochronological and geochemical data from the Nan Suture and Sukhothai Arc Terrane,the authors suggest that the andesitic rocks in the B.On ultramafic complex formed in a back-arc basin background,which connected the Jinghong and Nan back-arc basin during the Permian;while the andesitic tuff in the B.Kiophoulan-B.Houayhak belt erupted in the Sukhothai continental arc setting.
基金supported by the National Natural Science Foundation of China (Grant Nos.92155307,U1901602,42274058,42174106)the Shenzhen Science and Technology Program (Grant No.KQTD20170810111725321)the Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology (Grant No.2022B1212010002)。
文摘The Tethyan evolution depicts the continuous process of landmasses separating from the Gondwana continent in the south,drifting northwards,and subsequently colliding with the continents in the north over the past 500 million years.In this process,the Tethyan oceans that formed between the landmass and the southern or northern continents underwent growth,evolution,and eventual closure with the early Cenozoic India-Eurasia collision.However,the Tethyan lithosphere did not disappear but rather continued to evolve after entering into the deep Earth.The current position,morphology,and volume of the subducted Tethyan oceanic slabs in the deep mantle record the latest moment of this continuous evolution,providing critical constraints for Tethyan studies.This paper summarizes and analyzes the results of global-scale whole-mantle seismic tomography in the past nearly two decades,revealing a northwest-southeast seismically high-velocity anomaly,which is linearly distributed at depths of 1000–2000 km beneath the Tethyan realm and referred to as the Tethyan anomaly.By searching for an optimal linear combination of previous global seismic tomographic models to best match the known subducted slabs in the upper mantle,we observe that the Tethyan anomaly extends approximately 8700 km in length and 2600 km in width,exhibiting a parallel structure with northern and southern branches.Combining geological records of oceanic subduction initiation and previous geodynamic studies,this study suggests that the main body of the Tethyan anomaly represents the remnants of the subducted Neo-Tethyan oceanic slabs,which subducted from the Late Jurassic to the early Cenozoic.The northern branch consists of subducted slabs from the Neo-Tethys beneath the southern margin of Eurasia,while the southern branch likely reflects the intra-oceanic subducted slabs of Neo-Tethys during the Cretaceous.The western portion of the Tethyan anomaly may reflect remnants of Paleo-Tethys,while the eastern portion,towards India and the Bay of Bengal,shows signs of subduction towards the core-mantle boundary.Finally,this study discusses the future prospects of whole-mantle seismic tomographic studies focusing on the Tethyan realm.
