Determining the spatio-temporal distribution of the deformation tied to the India-Eurasian convergence and the impact of pre-existing weaknesses on the Cenozoic crustal deformation is significant for understanding how...Determining the spatio-temporal distribution of the deformation tied to the India-Eurasian convergence and the impact of pre-existing weaknesses on the Cenozoic crustal deformation is significant for understanding how the convergence between India and Eurasia contributed to the development of the Tibetan Plateau. The exhumation history of the northeastern Tibetan Plateau was addressed in this research using a new apatite fission track （AFT） study in the North Qaidam thrust belt （NQTB）. Three granite samples collected from the Qaidam Shan pluton in the north tied to the Qaidam Shan thrust, with AFT ages clustering in the Eocene to Miocene. The other thirteen samples obtained from the Luliang Shan and Yuka plutons in the south related to the Luliang Shan thrust and they have showed predominantly the Cretaceous AFT ages. Related thermal history modeling based on grain ages and track lengths indicates rapid cooling events during the Eocene-early Oligocene and since late Miocene within the Qaidam Shan, in contrast to those in the Cretaceous and since the Oligocene-Miocene in the Luliang Shan and Yuka region. The results, combined with published the Cretaceous thermochronological ages in the Qaidam Shan region, suggest that the NQTB had undergo rapid exhumation during the accretions along the southern Asian Andean-type margin prior to the India-Eurasian collision. The Cenozoic deformation initially took place in the North Qaidam thrust belt by the Eocene, which is consistent with the recent claim that the deformation of the northeastern Tibetan Plateau initiated in the Eocene as a response to continental collision between India and Eurasia. The immediate deformation responding to the collision is tentatively attributed to the preexisting weaknesses of the lithosphere, and therefore the deformation of the northeastern Tibetan Plateau should be regarded as a boundary-condition-dependent process.展开更多
The apatite fission track（AFT） ages and thermal modeling of the Longshoushan and deformation along the northern Hexi Corridor on the northern side of the Qinghai-Tibetan Plateau show that the Longshoushan along the ...The apatite fission track（AFT） ages and thermal modeling of the Longshoushan and deformation along the northern Hexi Corridor on the northern side of the Qinghai-Tibetan Plateau show that the Longshoushan along the northern corridor had experienced important multi-stage exhumations during the Late Mesozoic and Cenozoic. The AFT ages of 7 samples range from 31.9 Ma to 111.8 Ma.Thermal modeling of the AFT ages of the samples shows that the Longshoushan experienced significant exhumation during the Late Cretaceous to the Early Cenozoic（-130-25 Ma）. The Late Cretaceous exhumation of the Longshoushan may have resulted from the continuous compression between the Lhasa and Qiangtang blocks and the flat slab subduction of the Neo-Tethys oceanic plate, which affected wide regions across the Qinghai-Tibetan Plateau. During the Early Cenozoic, the Longshoushan still experienced exhumation, but this process was caused by the Indian-Eurasian collision. Since this time,the Longshoushan was in a stable stage for approximately 20 Ma and experienced erosion. Since -5 Ma,obvious tectonic deformation occurred along the entire northern Hexi Corridor, which has also been reported from the peripheral regions of the Qinghai-Tibetan Plateau, especially in the Qilianshan and northeastern margin of the plateau. The AFT ages and the Late Cenozoic deformation of the northern Hexi Corridor all indicate that the present northern boundary of the Qinghai-Tibetan Plateau is situated along the northern Hexi Corridor.展开更多
Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in ...Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in this study. The measured fission track apparent ages, combined with the simulated annealing mod- eling of the thermal history, have been used to reconstruct the thermal evolutionary histories of the samples and interpret the active history of the thrusts and faults in these areas. Thermal history mod- eling shows that earlier tectonic cooling occurred in the Garzê-Litang thrust in Miocene (~20―16 Ma) whereas the later cooling occurred mainly in the Longmen Shan thrust since ~5 Ma. Our study sug- gests that the margin of eastern Tibetan Plateau was extended by stages: through strike-slip faults deformations and related thrusts, the upper crust formed the Garzê-Litang margin in the Miocene epoch and then moved to the Longmen Shan margin since ~5 Ma. During this process, the deformations of different phases in the eastern Tibetan Plateau were absorbed by the thrusts within them and conse- quently the tectonic events of long-distance slip and extrusion up to hundreds of kilometers have not been found.展开更多
Since the Cenozoic,the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India-Asia collision.However,the mechanism and timing of these tectonic processes still remain debated.Here,using apat...Since the Cenozoic,the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India-Asia collision.However,the mechanism and timing of these tectonic processes still remain debated.Here,using apatite fission track dating and inverse thermal modeling,we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau.In contrast to previous views,we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites,indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times.In addition,we also suggest that the 5-2 Ma mantle-related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau,because it led to the increase in atmospheric CO_(2)level and a hotter upper crust than before,which are efficient for suddenly fast rock weathering and erosion.Finally,we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate.展开更多
Apatite fission-track dating and thermal-history modeling were carried out on samples from the Dabashan （大巴山）, a fold-thrust belt, northeast of the Sichuan （四川） Basin and east of the Tibetan Plateau. A first ...Apatite fission-track dating and thermal-history modeling were carried out on samples from the Dabashan （大巴山）, a fold-thrust belt, northeast of the Sichuan （四川） Basin and east of the Tibetan Plateau. A first cooling event in the Late Cretaceous is followed by a prolonged period of ther- mal stability with exhumation rates of 〈0.025 mm/a, as determined from age vs. elevation relationships. The preservation of age vs. elevations relationships and the lack of distinct age changes across tectonic structures indicate that the Dabashan fold-thrust belt formed prior to the Late Cretaceous, consistent with the current view of Triassic-Early Cretaceous shortening. Relatively short mean track lengths （-12 μm） indicate that the samples remained in the partial annealing zone for a prolonged time. The knick points in the best-fitting temperature-time models suggest that the onset of late-stage accelerated cooling commenced at 〈11 Ma. Related exhumation rates are 0.3-0.2 mm/a assuming geothermal gra- dients of 20 and 30 ℃/km. We speculate that this late-stage event results from eastward growth of the Tibetan Plateau and overstepping of the Sichuan Basin, it is likely responsible for the youthful mor- phology of the Dabashan.展开更多
The Tibetan Plateau geographically contains internal and external drainage areas based on the distributions of river flows and catchments.The internal and external drainage areas display similar highelevations,while t...The Tibetan Plateau geographically contains internal and external drainage areas based on the distributions of river flows and catchments.The internal and external drainage areas display similar highelevations,while their topographic reliefs are not comparable;the former shows a large low-relief surface,whereas the latter is characterized by relatively high relief.The eastern Lhasa terrane is a key tectonic component of the Tibetan Plateau.It is characterized by high topography and relief,but the thermal history of its basement remains relatively poorly constrained.In this study we report new apatite fission track data from the eastern part of the central Lhasa terrane to constrain the thermo-tectonic evolution of the external drainage area in the southern Tibetan Plateau.Twenty-one new AFT ages and associated thermal history models reveal that the basement underlying the external drainage area in southern Tibet experienced three main phases of rapid cooling in the Cenozoic.The Paleocene-early Eocene(-60–48 Ma)cooling was likely induced by crustal shortening and associated rock exhumation,due to accelerated northward subduction of the NeoTethys oceanic lithosphere.A subsequent cooling pulse lasted from the late Eocene to early Oligocene(-40–28 Ma),possibly due to the thickening and consequential erosion of the Lhasa lithosphere resulted from the continuous northward indentation of the India plate into Eurasia.The most recent rapid cooling event occurred in the middle Miocene-early Pliocene(-16–4 Ma),likely induced by accelerated incision of the Lhasa River and local thrust faulting.Our AFT ages and published low-temperature thermochronological data reveal that the external drainage area experienced younger cooling events compared with the internal drainage area,and that the associated differentiated topographic evolution initiated at ca.30 Ma.The contributing factors for the formation of the high-relief topography mainly contain active surface uplift,fault activity,and the enhanced incision of the Yarlung River.展开更多
The Sanjiang Tethys orogenic belt is located in the southeast side of the Qinghai-Tibet Plateau. It has undergone the opening and closing movements in different periods of Tethys oceans, complex accretive orogeny and ...The Sanjiang Tethys orogenic belt is located in the southeast side of the Qinghai-Tibet Plateau. It has undergone the opening and closing movements in different periods of Tethys oceans, complex accretive orogeny and strong mineralization from Paleozoic to Mesozoic. Using zircon fission track(ZFT) thermochronology, this study reveals the Sanjiang Tethys has experienced multi-stage tectonic activities during the Late Triassic–Cenozoic. The 15 ZFT ages with their decomposition components obtained from Sanjiang Tethysian region range from 212 to 19 Ma, which not only shows 6 age groups of 212, 179–172, 156–133, 121–96, 84–70 and 50–19 Ma, but also constrains the age limit of the tectonothermal events. These age groups recorded the Paleo-Tethys main and branches ocean opening/closure time. The age-elevation plot indicates the Sanjiang region had differential uplifting and exhumation and fast uplifting times of ca. 133, 116 and 80 Ma, coinciding with the age groups mentioned above. These results show new geochronological evidences and viewpoints.展开更多
基金funded by the National Science Foundation of China(Grant No.41102128,41330207,41372206,41472181,and 41402170)the National S&T Major Project(Grant No.2016ZX05008-001 and 2016ZX05003-001)+1 种基金Research Funds from Bureau of Education Zhejiang Province(Grant No.Y201019040)the Fundamental Research Funds for the Central Universities(Grant No.2016FZA3007)
文摘Determining the spatio-temporal distribution of the deformation tied to the India-Eurasian convergence and the impact of pre-existing weaknesses on the Cenozoic crustal deformation is significant for understanding how the convergence between India and Eurasia contributed to the development of the Tibetan Plateau. The exhumation history of the northeastern Tibetan Plateau was addressed in this research using a new apatite fission track （AFT） study in the North Qaidam thrust belt （NQTB）. Three granite samples collected from the Qaidam Shan pluton in the north tied to the Qaidam Shan thrust, with AFT ages clustering in the Eocene to Miocene. The other thirteen samples obtained from the Luliang Shan and Yuka plutons in the south related to the Luliang Shan thrust and they have showed predominantly the Cretaceous AFT ages. Related thermal history modeling based on grain ages and track lengths indicates rapid cooling events during the Eocene-early Oligocene and since late Miocene within the Qaidam Shan, in contrast to those in the Cretaceous and since the Oligocene-Miocene in the Luliang Shan and Yuka region. The results, combined with published the Cretaceous thermochronological ages in the Qaidam Shan region, suggest that the NQTB had undergo rapid exhumation during the accretions along the southern Asian Andean-type margin prior to the India-Eurasian collision. The Cenozoic deformation initially took place in the North Qaidam thrust belt by the Eocene, which is consistent with the recent claim that the deformation of the northeastern Tibetan Plateau initiated in the Eocene as a response to continental collision between India and Eurasia. The immediate deformation responding to the collision is tentatively attributed to the preexisting weaknesses of the lithosphere, and therefore the deformation of the northeastern Tibetan Plateau should be regarded as a boundary-condition-dependent process.
基金funded by the National Natural Science Foundation of China(No.41572190)the National Program on Key Basic Research Project from the Ministry of Science and Technology of China(No.2015CB453002)the China Geological Survey(Nos.12120115070101,1212010611806,1212010611817)
文摘The apatite fission track（AFT） ages and thermal modeling of the Longshoushan and deformation along the northern Hexi Corridor on the northern side of the Qinghai-Tibetan Plateau show that the Longshoushan along the northern corridor had experienced important multi-stage exhumations during the Late Mesozoic and Cenozoic. The AFT ages of 7 samples range from 31.9 Ma to 111.8 Ma.Thermal modeling of the AFT ages of the samples shows that the Longshoushan experienced significant exhumation during the Late Cretaceous to the Early Cenozoic（-130-25 Ma）. The Late Cretaceous exhumation of the Longshoushan may have resulted from the continuous compression between the Lhasa and Qiangtang blocks and the flat slab subduction of the Neo-Tethys oceanic plate, which affected wide regions across the Qinghai-Tibetan Plateau. During the Early Cenozoic, the Longshoushan still experienced exhumation, but this process was caused by the Indian-Eurasian collision. Since this time,the Longshoushan was in a stable stage for approximately 20 Ma and experienced erosion. Since -5 Ma,obvious tectonic deformation occurred along the entire northern Hexi Corridor, which has also been reported from the peripheral regions of the Qinghai-Tibetan Plateau, especially in the Qilianshan and northeastern margin of the plateau. The AFT ages and the Late Cenozoic deformation of the northern Hexi Corridor all indicate that the present northern boundary of the Qinghai-Tibetan Plateau is situated along the northern Hexi Corridor.
基金Supported by Chinese Academy of Sciences (Grant No. KZCX3-SW-143)Chinese Ministry of Science and Technology (Grant No. 2002CB412602) the National Natural Science Foundation of China (Grant No. 40234049)
文摘Granites sampled from Garzê-Litang thrust, Longmen Shan thrust, Garzê and Litang strike-slip faults in the eastern Tibetan Plateau have been analyzed with apatite fission track thermochronological method in this study. The measured fission track apparent ages, combined with the simulated annealing mod- eling of the thermal history, have been used to reconstruct the thermal evolutionary histories of the samples and interpret the active history of the thrusts and faults in these areas. Thermal history mod- eling shows that earlier tectonic cooling occurred in the Garzê-Litang thrust in Miocene (~20―16 Ma) whereas the later cooling occurred mainly in the Longmen Shan thrust since ~5 Ma. Our study sug- gests that the margin of eastern Tibetan Plateau was extended by stages: through strike-slip faults deformations and related thrusts, the upper crust formed the Garzê-Litang margin in the Miocene epoch and then moved to the Longmen Shan margin since ~5 Ma. During this process, the deformations of different phases in the eastern Tibetan Plateau were absorbed by the thrusts within them and conse- quently the tectonic events of long-distance slip and extrusion up to hundreds of kilometers have not been found.
基金supported by National Natural Science Foundation of China(Grant Nos.42025301,41730213 and 41890831)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0702)+2 种基金Hong Kong RGC GRF(Grant No.17307918)HKU Internal Grants for Member of Chinese Academy of Sciences(Grant No.102009906)for Distinguished Research Achievement Award(Grant No.102010100)。
文摘Since the Cenozoic,the Tibetan Plateau has experienced large-scale uplift and outgrowth due to the India-Asia collision.However,the mechanism and timing of these tectonic processes still remain debated.Here,using apatite fission track dating and inverse thermal modeling,we explore the mechanism of different phases of rapid cooling for different batholiths and intrusions in the southeastern Tibetan Plateau.In contrast to previous views,we find that the coeval granitic batholith exposed in the same tectonic zone experienced differential fast uplift in different sites,indicating that the present Tibetan Plateau was the result of differential uplift rather than the entire lithosphere uplift related to lithospheric collapse during Cenozoic times.In addition,we also suggest that the 5-2 Ma mantle-related magmatism should be regarded as the critical trigger for the widely coeval cooling event in the southeastern Tibetan Plateau,because it led to the increase in atmospheric CO_(2)level and a hotter upper crust than before,which are efficient for suddenly fast rock weathering and erosion.Finally,we propose that the current landform of the southeastern Tibetan Plateau was the combined influences of tectonic and climate.
基金supported by the National Natural Science Foundation of China (No. 40902038)the Petro China Innova-tion Foundation (No. 2009D-5006-01-08)the Project of China Geological Survey (No. 12120113094200)
文摘Apatite fission-track dating and thermal-history modeling were carried out on samples from the Dabashan （大巴山）, a fold-thrust belt, northeast of the Sichuan （四川） Basin and east of the Tibetan Plateau. A first cooling event in the Late Cretaceous is followed by a prolonged period of ther- mal stability with exhumation rates of 〈0.025 mm/a, as determined from age vs. elevation relationships. The preservation of age vs. elevations relationships and the lack of distinct age changes across tectonic structures indicate that the Dabashan fold-thrust belt formed prior to the Late Cretaceous, consistent with the current view of Triassic-Early Cretaceous shortening. Relatively short mean track lengths （-12 μm） indicate that the samples remained in the partial annealing zone for a prolonged time. The knick points in the best-fitting temperature-time models suggest that the onset of late-stage accelerated cooling commenced at 〈11 Ma. Related exhumation rates are 0.3-0.2 mm/a assuming geothermal gra- dients of 20 and 30 ℃/km. We speculate that this late-stage event results from eastward growth of the Tibetan Plateau and overstepping of the Sichuan Basin, it is likely responsible for the youthful mor- phology of the Dabashan.
基金supported by National Key Research and Development Program of China(2022YFC2905001,2018YFC0604105)the Opening Foundation of Ministry of Natural Resources Key Laboratory for Mineral Deposits Research,Chengdu University of Technology(grant number:gzck202104)+2 种基金the Fund for Scientific Research-Flanders(FWO,Bilateral Project VS06520N)China Scholarship Council(201908320260,201806190214)support for W.Su and Z.He for their research stay in Belgium.S.Glorie is supported by an Australian Research Council Future Fellowship(FT210100906)。
文摘The Tibetan Plateau geographically contains internal and external drainage areas based on the distributions of river flows and catchments.The internal and external drainage areas display similar highelevations,while their topographic reliefs are not comparable;the former shows a large low-relief surface,whereas the latter is characterized by relatively high relief.The eastern Lhasa terrane is a key tectonic component of the Tibetan Plateau.It is characterized by high topography and relief,but the thermal history of its basement remains relatively poorly constrained.In this study we report new apatite fission track data from the eastern part of the central Lhasa terrane to constrain the thermo-tectonic evolution of the external drainage area in the southern Tibetan Plateau.Twenty-one new AFT ages and associated thermal history models reveal that the basement underlying the external drainage area in southern Tibet experienced three main phases of rapid cooling in the Cenozoic.The Paleocene-early Eocene(-60–48 Ma)cooling was likely induced by crustal shortening and associated rock exhumation,due to accelerated northward subduction of the NeoTethys oceanic lithosphere.A subsequent cooling pulse lasted from the late Eocene to early Oligocene(-40–28 Ma),possibly due to the thickening and consequential erosion of the Lhasa lithosphere resulted from the continuous northward indentation of the India plate into Eurasia.The most recent rapid cooling event occurred in the middle Miocene-early Pliocene(-16–4 Ma),likely induced by accelerated incision of the Lhasa River and local thrust faulting.Our AFT ages and published low-temperature thermochronological data reveal that the external drainage area experienced younger cooling events compared with the internal drainage area,and that the associated differentiated topographic evolution initiated at ca.30 Ma.The contributing factors for the formation of the high-relief topography mainly contain active surface uplift,fault activity,and the enhanced incision of the Yarlung River.
基金supported by the National Program on Key Basic Research Project(973 Program)(No.2015CB452606)the National Natural Science Foundation of China(Nos.41730427,41172088)
文摘The Sanjiang Tethys orogenic belt is located in the southeast side of the Qinghai-Tibet Plateau. It has undergone the opening and closing movements in different periods of Tethys oceans, complex accretive orogeny and strong mineralization from Paleozoic to Mesozoic. Using zircon fission track(ZFT) thermochronology, this study reveals the Sanjiang Tethys has experienced multi-stage tectonic activities during the Late Triassic–Cenozoic. The 15 ZFT ages with their decomposition components obtained from Sanjiang Tethysian region range from 212 to 19 Ma, which not only shows 6 age groups of 212, 179–172, 156–133, 121–96, 84–70 and 50–19 Ma, but also constrains the age limit of the tectonothermal events. These age groups recorded the Paleo-Tethys main and branches ocean opening/closure time. The age-elevation plot indicates the Sanjiang region had differential uplifting and exhumation and fast uplifting times of ca. 133, 116 and 80 Ma, coinciding with the age groups mentioned above. These results show new geochronological evidences and viewpoints.
