The uplift and exhumation process in the Tianshan orogen since the late Paleozoic were likely related to the preservation of ore deposits. This study involved reconstructing the whole tectonic thermal history of the O...The uplift and exhumation process in the Tianshan orogen since the late Paleozoic were likely related to the preservation of ore deposits. This study involved reconstructing the whole tectonic thermal history of the Ouxidaban pluton in central South Tianshan Mountains based on hornblende/plagioclase Ar-Ar and zircon/apatite （U-Th）/He methods. The thermal history and uplift process of central South Tianshan Mountains since the late Paleozoic were analyzed according to the results of previous works and cooling/exhumation rate features. The hornblende yields a plateau age of 382.6_＋3.6 Ma, and the plagio- clase yields a weighted mean age of 265.8_＋4.9 Ma. The Ouxidaban pluton yields weighted mean zircon （U-Th）/He age of 185.8±4.3 Ma and apatite （U-Th）/He age of 31.1±2.9 Ma, respectively. Five stages of tectonic thermal history of South Tianshan Mountains since the late Paleozoic could be discriminated by the cooling curve and modeling simulation： （1） from the latest Silurian to Late Devonian, the average cooling rate of the Ouxidaban pluton was 7.84℃/Ma; （2） from the Late De- vonian to the latest Middle Permian, the average cooling rate was about 2.07℃/Ma; （3） from the latest Middle Permian to the middle Eocene, the cooling rate decreased to about 0.68℃/Ma, suggesting that the tectonic activity was gentle at this time; （4） a sudden increase of the cooling rate （5.00℃/Ma） and the exhumation rate （0.17 mrn/a）, and crustal exhumation of -1.83 km indicated that the Ouxidaban pluton would suffer a rapid uplift event during the Eocene （-46-35 Ma）; （5） since the middle Eocene, the rapid uplift was sustained, and the average cooling rate since then has been 1.14℃/Ma with an exhumation rate of about 0.04 mm/a and an exhumation thickness of 1.33 km. The strong uplift since the Cenozoic would be related to a far-field effect from the Indian and Eurasian plates＇ collision. However, it was hysteretic that the remote effect was observed in the Tianshan orogenic belt.展开更多
The Huangshan Mountain Geopark is an important geological landmark and tourist attraction.In this paper,we apply fission track dating to examine the uplift and exhumation processes that created the Huangshan Mountains...The Huangshan Mountain Geopark is an important geological landmark and tourist attraction.In this paper,we apply fission track dating to examine the uplift and exhumation processes that created the Huangshan Mountains and provide a timeline for their development.In addition to being an important scientific contribution,this information can be used on guided tours and to promote tourism.The results of eight apatite fission-track analyses suggest three age groups:56,45-30,and 15 Ma.These age groups are related to the uplifting-erosion processes involved in forming ancient multilevel denudation planes at 85-50,45-30,and 24-5 Ma,respectively.The scenic area has experienced three stages of thermal evolution.The first stage occurred before 80 Ma and the third stage after 13 Ma.The three stages had varying cooling rates:2.69,0.62,and 4.23°C/Ma,respectively.Uplifting rates also varied:0.08,0.02,and 0.12 mm/a.The uplifting ranges were also variable:1.14,1.57,and 4.00 km,respectively.Significant uplifting differences between diverse areas are obvious and there were four magnitudes of cumulative uplifting range:4060-3950,3760-3490,3190-3070,and 2650 m.The surface uplifting range varied from 450 to 2230 m.Denudation and uplifting amount averaged 2340 and 3400 m,respectively.The 1060 m difference between them is the average elevation at present.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41473053)China Geological Survey(Grant No.12120113015600)Chinese Ministry of Land and Resources(Grant Nos.201511064-2&201211074-05)
文摘The uplift and exhumation process in the Tianshan orogen since the late Paleozoic were likely related to the preservation of ore deposits. This study involved reconstructing the whole tectonic thermal history of the Ouxidaban pluton in central South Tianshan Mountains based on hornblende/plagioclase Ar-Ar and zircon/apatite （U-Th）/He methods. The thermal history and uplift process of central South Tianshan Mountains since the late Paleozoic were analyzed according to the results of previous works and cooling/exhumation rate features. The hornblende yields a plateau age of 382.6_＋3.6 Ma, and the plagio- clase yields a weighted mean age of 265.8_＋4.9 Ma. The Ouxidaban pluton yields weighted mean zircon （U-Th）/He age of 185.8±4.3 Ma and apatite （U-Th）/He age of 31.1±2.9 Ma, respectively. Five stages of tectonic thermal history of South Tianshan Mountains since the late Paleozoic could be discriminated by the cooling curve and modeling simulation： （1） from the latest Silurian to Late Devonian, the average cooling rate of the Ouxidaban pluton was 7.84℃/Ma; （2） from the Late De- vonian to the latest Middle Permian, the average cooling rate was about 2.07℃/Ma; （3） from the latest Middle Permian to the middle Eocene, the cooling rate decreased to about 0.68℃/Ma, suggesting that the tectonic activity was gentle at this time; （4） a sudden increase of the cooling rate （5.00℃/Ma） and the exhumation rate （0.17 mrn/a）, and crustal exhumation of -1.83 km indicated that the Ouxidaban pluton would suffer a rapid uplift event during the Eocene （-46-35 Ma）; （5） since the middle Eocene, the rapid uplift was sustained, and the average cooling rate since then has been 1.14℃/Ma with an exhumation rate of about 0.04 mm/a and an exhumation thickness of 1.33 km. The strong uplift since the Cenozoic would be related to a far-field effect from the Indian and Eurasian plates＇ collision. However, it was hysteretic that the remote effect was observed in the Tianshan orogenic belt.
基金supported by National Natural Science Foundation of China(Grant Nos.40872141,40872068and10475093)the "111" Project(Grant No.B07011)National Basic Research Program of China(Grant No.2009CB421006)
文摘The Huangshan Mountain Geopark is an important geological landmark and tourist attraction.In this paper,we apply fission track dating to examine the uplift and exhumation processes that created the Huangshan Mountains and provide a timeline for their development.In addition to being an important scientific contribution,this information can be used on guided tours and to promote tourism.The results of eight apatite fission-track analyses suggest three age groups:56,45-30,and 15 Ma.These age groups are related to the uplifting-erosion processes involved in forming ancient multilevel denudation planes at 85-50,45-30,and 24-5 Ma,respectively.The scenic area has experienced three stages of thermal evolution.The first stage occurred before 80 Ma and the third stage after 13 Ma.The three stages had varying cooling rates:2.69,0.62,and 4.23°C/Ma,respectively.Uplifting rates also varied:0.08,0.02,and 0.12 mm/a.The uplifting ranges were also variable:1.14,1.57,and 4.00 km,respectively.Significant uplifting differences between diverse areas are obvious and there were four magnitudes of cumulative uplifting range:4060-3950,3760-3490,3190-3070,and 2650 m.The surface uplifting range varied from 450 to 2230 m.Denudation and uplifting amount averaged 2340 and 3400 m,respectively.The 1060 m difference between them is the average elevation at present.
