The Yanji area,northeastern China,a part of the orogenic collage between the North China Block in the south and the Jiamusi-Khanka Massifs in the northeast,is the most likely location where the Pacific Plate subductio...The Yanji area,northeastern China,a part of the orogenic collage between the North China Block in the south and the Jiamusi-Khanka Massifs in the northeast,is the most likely location where the Pacific Plate subduction・related magmatic activities and subsequent exhumation processes occurred.Here,we report new low-temperature thermochronology of apatite and zircon data from the granitoid samples in the Yanji area.The exhumation rates of Tianfozhishan,Yanji area,were〜0.049 and〜0.073 mm/year,interpreted from the elevations and apatite and zircon fission track ages,respectively.The exhumation,integrated with the geological setting,suggested that the paleogeothermal gradient of the Tianfozhishan,even extending to the Yanji area,was possibly to be greater than 35℃/km in the Late Cretaceous.The thermal history modeling of the data indicates a basically similar pattern,but the various timing for different samples between the Oligocene-Early Miocene and the Middle Miocene in the Yanji area.We hence conclude that a fourstages of cooling,from〜6.7℃/Ma(during the Late Cretaceous),to〜0.8℃/Ma(during the Late Cretaceous to the Oligocene-Early Miocene),then to〜2-3℃/Ma with varied styles(between the Oligocene-Early Miocene and the Middle Miocene),and finally to<0.2℃/Ma(since the Middle Miocene),has taken place through the exhumation of the Yanji area.The maximum exhumation is>3 km under a reasonable paleogeothermal gradient(>35℃/km),speculated from the possible exhumation rate of Tianfozhishan.Combined with the tectonic setting,this exhumation,including two stages of pronounced tectonic uplift and denudation and two stages of weak exhumation driven by the low regional erosion rate,is possibly related to the subduction of the Pacific Plate beneath the Eurasian Plate since the Late Cretaceous.This study used more robust evidence to propose higher paleogeothermal gradient(>35℃/km),reflecting exhumation of>3 km in the Yanji area since the Late Cretaceous.展开更多
Yanji is the biggest China Korean inhabited city. Based on a newly finished research project, this paper discusses strategic problems about Yanji towards 21st century. The general point of the authors is that at the b...Yanji is the biggest China Korean inhabited city. Based on a newly finished research project, this paper discusses strategic problems about Yanji towards 21st century. The general point of the authors is that at the beginning of new century, Yanji will play a more important role in Tumen River Delta development, regional economy cooperation in Korea Peninsula as well as Northeast Asia, and it will develop to be an important central city in this area. This paper puts forwards Yanji City’s developing goal, urban nature, and urban size, probes its regional orientation, and further probes how to establish The Yanji Urban Economy Cooperation Zone. The authors think that Yanji should depend on its intellect resources and other characteristic resources. Industry development need to pay much attention to modern agriculture, tertiary industry (especially commerce, trade and tourism) and dominant industries, and high-tech industry must give a special care, in order to establish a light industrial structure.展开更多
The ratification and implementation of Cooperation and Development Planning Outline of Tumen River Region in China will have great significance to the frontier opening-up in the Northeast Asia Region of China, economi...The ratification and implementation of Cooperation and Development Planning Outline of Tumen River Region in China will have great significance to the frontier opening-up in the Northeast Asia Region of China, economic cooperation in sub-region of Tumen River, and the development of tourism in forerunner zone of "Changchun-Jilin-Tumen". Yanji City is regarded as the fulcrum Chinese city in "Golden Triangle" of Northeast Asian economic zone, whose breakthrough and development in tourism and recreation is in face of new situation. Based on analyzing strength, weakness, opportunity and threat of development of ReBAM in Yanji City, our research further deepens the systematic understanding of development of ReBAM in Yanji City. And we get the conclusion that Yanji city should take the opportunity of cooperation and development of Tumen River Region in China on the basis of newly fledged ReBAM at present, to exploit the potential of market demand for ReBAM, and implement proactive growth-oriented strategy to further improve urban tourism structural system in Yanji City.展开更多
The authors studied zircon U-Pb age and geochemical data of Baicaogou tuff in Yanji,Jilin Province.The results indicate that the rocks formed in Early Cretaceous( 125. 6 ± 2. 3 Ma). Geochemically,these tuffs have...The authors studied zircon U-Pb age and geochemical data of Baicaogou tuff in Yanji,Jilin Province.The results indicate that the rocks formed in Early Cretaceous( 125. 6 ± 2. 3 Ma). Geochemically,these tuffs have high Si O2 and total Na2 O + K2 O,low Mg O and Fe O,and they belong to metaluminous series,the rock are enriched in LREEs and LILEs,depleted in HREEs and HFSEs such as Nb,Ta,Ti,and P,exhibiting an affinity to I-type granite. All these characteristics implied that the volcanic rocks were derived from partial melting of lower crust. Combined with the geochronology and geochemical features of the coeval igneous rocks within NE China,it is concluded that Yanji area was in a back-arc extensional setting in response to the subduction of the Paleo-Pacific Plate beneath the Eurasian Plate.展开更多
Ar-Ar dating results of late Mesozoic-Cenozoic volcanic rocks from the Yanji area, NE China provide a new volcano-sedimentary stratigraphic framework. The previously defined “Triassic-Jurassic” volcanic rocks (inclu...Ar-Ar dating results of late Mesozoic-Cenozoic volcanic rocks from the Yanji area, NE China provide a new volcano-sedimentary stratigraphic framework. The previously defined “Triassic-Jurassic” volcanic rocks (including those from Sanxianling, Tuntianying, Tianqiaoling and Jingouling Fms.) were erupted during 118―106 Ma, corresponding to Early Cretaceous. The new eruption age span is slightly younger than the main stage (130―120 Ma) of the extensive magmatism in the eastern Central Asian Orogenic Belt and its adjacent regions. Subduction-related adakites occurring in the previously defined Quanshuicun Fm. were extruded at ca. 55 Ma. Based on these new Ar-Ar ages, the late Mesozoic to Palaeocene volcano-sedimentary sequences is rebuilt as: Tuopangou Fm., Sanxianling/Tuntianying Fm. (118―115 Ma), Malugou/Tianqiaoling Fm. (K1), Huoshanyan/Jingouling Fm. (108―106 Ma), Changcai Fm. (K2), Quanshuicun Fm. (~55 Ma) and Dalazi Fm. Our results suggest that subduction of the Pa- laeo-Pacific Ocean beneath the East Asian continental margin occurred during 106 to 55 Ma, consistent with the paleomagnetic observations and magmatic records which indicated that the Izanagi-Farallon ridge subduction beneath the southwestern Japan took place during 95―65 Ma.展开更多
基金supported by the DREAM project of MOST China (2016YFC0600406)the National Natural Science Foundation of China (Grant Nos. 41072158, 41372227)
文摘The Yanji area,northeastern China,a part of the orogenic collage between the North China Block in the south and the Jiamusi-Khanka Massifs in the northeast,is the most likely location where the Pacific Plate subduction・related magmatic activities and subsequent exhumation processes occurred.Here,we report new low-temperature thermochronology of apatite and zircon data from the granitoid samples in the Yanji area.The exhumation rates of Tianfozhishan,Yanji area,were〜0.049 and〜0.073 mm/year,interpreted from the elevations and apatite and zircon fission track ages,respectively.The exhumation,integrated with the geological setting,suggested that the paleogeothermal gradient of the Tianfozhishan,even extending to the Yanji area,was possibly to be greater than 35℃/km in the Late Cretaceous.The thermal history modeling of the data indicates a basically similar pattern,but the various timing for different samples between the Oligocene-Early Miocene and the Middle Miocene in the Yanji area.We hence conclude that a fourstages of cooling,from〜6.7℃/Ma(during the Late Cretaceous),to〜0.8℃/Ma(during the Late Cretaceous to the Oligocene-Early Miocene),then to〜2-3℃/Ma with varied styles(between the Oligocene-Early Miocene and the Middle Miocene),and finally to<0.2℃/Ma(since the Middle Miocene),has taken place through the exhumation of the Yanji area.The maximum exhumation is>3 km under a reasonable paleogeothermal gradient(>35℃/km),speculated from the possible exhumation rate of Tianfozhishan.Combined with the tectonic setting,this exhumation,including two stages of pronounced tectonic uplift and denudation and two stages of weak exhumation driven by the low regional erosion rate,is possibly related to the subduction of the Pacific Plate beneath the Eurasian Plate since the Late Cretaceous.This study used more robust evidence to propose higher paleogeothermal gradient(>35℃/km),reflecting exhumation of>3 km in the Yanji area since the Late Cretaceous.
基金the auspices of the Chinese Academy of Sciences(REGION IV - 9907) and Yanji Municipal Government.
文摘Yanji is the biggest China Korean inhabited city. Based on a newly finished research project, this paper discusses strategic problems about Yanji towards 21st century. The general point of the authors is that at the beginning of new century, Yanji will play a more important role in Tumen River Delta development, regional economy cooperation in Korea Peninsula as well as Northeast Asia, and it will develop to be an important central city in this area. This paper puts forwards Yanji City’s developing goal, urban nature, and urban size, probes its regional orientation, and further probes how to establish The Yanji Urban Economy Cooperation Zone. The authors think that Yanji should depend on its intellect resources and other characteristic resources. Industry development need to pay much attention to modern agriculture, tertiary industry (especially commerce, trade and tourism) and dominant industries, and high-tech industry must give a special care, in order to establish a light industrial structure.
基金Supported by National Natural Science Foundation (41071333)the 211 Key Discipline Building Project of Yanbian University
文摘The ratification and implementation of Cooperation and Development Planning Outline of Tumen River Region in China will have great significance to the frontier opening-up in the Northeast Asia Region of China, economic cooperation in sub-region of Tumen River, and the development of tourism in forerunner zone of "Changchun-Jilin-Tumen". Yanji City is regarded as the fulcrum Chinese city in "Golden Triangle" of Northeast Asian economic zone, whose breakthrough and development in tourism and recreation is in face of new situation. Based on analyzing strength, weakness, opportunity and threat of development of ReBAM in Yanji City, our research further deepens the systematic understanding of development of ReBAM in Yanji City. And we get the conclusion that Yanji city should take the opportunity of cooperation and development of Tumen River Region in China on the basis of newly fledged ReBAM at present, to exploit the potential of market demand for ReBAM, and implement proactive growth-oriented strategy to further improve urban tourism structural system in Yanji City.
文摘The authors studied zircon U-Pb age and geochemical data of Baicaogou tuff in Yanji,Jilin Province.The results indicate that the rocks formed in Early Cretaceous( 125. 6 ± 2. 3 Ma). Geochemically,these tuffs have high Si O2 and total Na2 O + K2 O,low Mg O and Fe O,and they belong to metaluminous series,the rock are enriched in LREEs and LILEs,depleted in HREEs and HFSEs such as Nb,Ta,Ti,and P,exhibiting an affinity to I-type granite. All these characteristics implied that the volcanic rocks were derived from partial melting of lower crust. Combined with the geochronology and geochemical features of the coeval igneous rocks within NE China,it is concluded that Yanji area was in a back-arc extensional setting in response to the subduction of the Paleo-Pacific Plate beneath the Eurasian Plate.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40373018 and 40334043) the Chinese Academy of Sciences (Grant Nos. KZCX2-104 and GIGCX-04-04)
文摘Ar-Ar dating results of late Mesozoic-Cenozoic volcanic rocks from the Yanji area, NE China provide a new volcano-sedimentary stratigraphic framework. The previously defined “Triassic-Jurassic” volcanic rocks (including those from Sanxianling, Tuntianying, Tianqiaoling and Jingouling Fms.) were erupted during 118―106 Ma, corresponding to Early Cretaceous. The new eruption age span is slightly younger than the main stage (130―120 Ma) of the extensive magmatism in the eastern Central Asian Orogenic Belt and its adjacent regions. Subduction-related adakites occurring in the previously defined Quanshuicun Fm. were extruded at ca. 55 Ma. Based on these new Ar-Ar ages, the late Mesozoic to Palaeocene volcano-sedimentary sequences is rebuilt as: Tuopangou Fm., Sanxianling/Tuntianying Fm. (118―115 Ma), Malugou/Tianqiaoling Fm. (K1), Huoshanyan/Jingouling Fm. (108―106 Ma), Changcai Fm. (K2), Quanshuicun Fm. (~55 Ma) and Dalazi Fm. Our results suggest that subduction of the Pa- laeo-Pacific Ocean beneath the East Asian continental margin occurred during 106 to 55 Ma, consistent with the paleomagnetic observations and magmatic records which indicated that the Izanagi-Farallon ridge subduction beneath the southwestern Japan took place during 95―65 Ma.
