As part of the mosaic of micro-continents within the Central Asian Orogenic Belt(CAOB), the Xing’anAirgin Sum Block(XAB) features increasingly-recognized Meso-Neoproterozoic geological records. However, the origin, t...As part of the mosaic of micro-continents within the Central Asian Orogenic Belt(CAOB), the Xing’anAirgin Sum Block(XAB) features increasingly-recognized Meso-Neoproterozoic geological records. However, the origin, temporal-spatial distribution of ancient materials, and their roles in crust evolution remain to debate. This paper presents an integrated study of zircon U-Pb ages and Hf-O isotopes for Mesoproterozoic and Paleozoic granites from the Erenhot region of central Inner Mongolia, along eastern CAOB. The intrusion of 1450 Ma syenogranite denotes that the Precambrian basement of XAB extends from Sonid Zuoqi westward to Erenhot. The 384 and 281 Ma monzogranites containing Mesoproterozoic xenocrystic zircons possess Proterozoic-dominant two-stage Hf model ages, further suggesting the wide existence of Proterozoic crust beneath western XAB. Cyclic Proterozoic crustal growth and reworking seem to show close linkages with the orogenesis during relevant supercontinent cycles. 1450-1360 Ma juvenile crustal growth at Erenhot and synchronous ancient crust reworking at Sonid Zuoqi and Abagaqi were likely resulted from retreating subduction involved in Columbia breakup, while 1.2-1.0 Ga reworking and 0.9-0.7 Ga growth events within the Erenhot basement might respond to assembly and breakup of Rodinia, respectively. Besides, our work confirms that reworking of Neoproterozoic crust played important roles during Paleozoic multi-stage accretion of CAOB.展开更多
The exposed area of igneous rocks in East Kunlun Mountains is very large and they made a magmatic arc belt broad in scale. The intrusive rocks are mainly of Hercynian—Indo\|Sinian cycle and less of Caledonian and Yan...The exposed area of igneous rocks in East Kunlun Mountains is very large and they made a magmatic arc belt broad in scale. The intrusive rocks are mainly of Hercynian—Indo\|Sinian cycle and less of Caledonian and Yanshanian cycle [1～2] . During the geological mapping of 1∶250000 of Donggeicuonahu area, we firstly found the evidence of intrusive rock of Jinning cycle. Intrusive rocks of Jinning cycle, whose exposed area is about 30km, are located in Waliaoga\|Shaxiong area among East Kunlun magmatic arc belt and are composed of two intrusive bodies. The rock types of Jinning cycle are mainly trondjemite and tonalite. Their wall rocks are Baishahe Group of Paleo\|Proterozoic and was intruded by Hercynian-Indo\|Sinian cycle granodiorite . The wall rock types are mainly banded amphibolite,biotite\|plagioclase schist,leptynite,leptite,banded marble and mica\|schist , their metamorphic condition is overall middle amphibole facies , partly granulite facies , tectonic deformation was mainly of flowage fold and flowage shear in middle and deep levers. Although intrusive rocks of Jinning cycle had undergone intensive metamorphism and deformation, they also preserve the intrusive appearance and are uniform in field. We can see intrusive contacted with wall rock or infolded the basic inclusions. Gneissosity is very common in intrusive rocks of Jinning cycle. Even though intensive metamorphism and deformation lead to interlude between intrusive body and wall rock, most wall rock exists in intrusive rocks as giant roof or inclusions in general, we can see intrusive contacted between intrusive body and wall rock locally. Intrusive rocks are hoar color, meso\|coarse grain lepido\|granoblastic texture , minerals are mainly plagioclase evidence to study the forming and evolution of orogeny of Jinning and Caledonian cycle.展开更多
Deep crustal rocks of the Early Proterozoic orogenic belt (DCR)in Daqingshan area mainly included the synorogenicmetamorphic khondalite series and reworked Archeanbasement granulites. During the early stage about 1900...Deep crustal rocks of the Early Proterozoic orogenic belt (DCR)in Daqingshan area mainly included the synorogenicmetamorphic khondalite series and reworked Archeanbasement granulites. During the early stage about 1900～1800 Ma, the DCR consisted of five huge slices which obducted over and stacked up along a series of hightemperature shear zone (HTSZ), and were subsequently uplifted from the deep crustal level to the middle one accompanied with granuliteamphibolite facies retrometamorphic reworking in HTSZ. From 1800～1700 Ma, some slices and HTSZ mentioned above were oveprinted by several lowtemperature shear zone (LTSZ), of which the lowangle oblique thrusts caused these DCR to uplift again from the middle crustal level to the shallow one, and experienced retrometamorphic reworking of greenschist facies. These two stages of uplifting processes should be included in an entire Early Proterozoic orogenic cycle.展开更多
The West Kunlun orogenic belt, one of the least studied areas in China, is located at the junction between the Qinghai—Tibetan Plateau and Tarim Basin and has undergone intense tectonic action and frequent magmatism....The West Kunlun orogenic belt, one of the least studied areas in China, is located at the junction between the Qinghai—Tibetan Plateau and Tarim Basin and has undergone intense tectonic action and frequent magmatism.The West Kunlun orogenic belt can be divided into five tectonic\|magmatic evolution stages according to the character of the igneous rocks, metamorphic rocks, sedimentation mode, tectonic phases and isotopic ages(Fig 1).Active stages have dominated with only short intervening stable stages. This kind of evolution is not simply repeated but that a later stage is elevation and development of its former stage.Space\|time distribution of granitoids varies with each different tectonic\| magmatic stage as well as within different periods of the same tectonic\| magmatism stage. Take time into condition , It is an important turning movement of tectonics\|magmatism evolution during the Indo\|Sinian movement, as space the middle fault (Jiang Chunfa 1982) of the West Kunlun orogenic belt is a significant border o f tectonics\|magmatism evolution. Granitoids formed before Indo\|Sinian movement are mainly distributed to the north of the middle fault of West Kunlun. These granitoids are mostly granites of early and middle Proterozoic, Caledonian and Hercynian ages. A unique control on the granitoid evolution is that they become younger from NE to SW, crossing the regional structure line. Granitoids formed after Indo\|Sinian movement are mainly distributed to the south of the middle fault. But distribution of granitoids of early Yanshan cycle cut across the middle fault of West Kunlun Mountain. Their age distribution shows a bidirectional control with the granitoids becoming younger across the regional structural lines from NE and SW boundary fault to the interior of the fracture belts.展开更多
基金Projects(41873035,41802053) supported by the National Natural Science Foundation of ChinaProject(ZD2021015) supported by the Science and Technology Project of Hebei Education Department,China+1 种基金Project(SCRM2116) supported by the Opening Foundation of Hebei Key Laboratory of Strategic Critical Mineral Resources,ChinaProject(202045004) supported by the Scientific Research Starting Foundation of Central South University,China。
文摘As part of the mosaic of micro-continents within the Central Asian Orogenic Belt(CAOB), the Xing’anAirgin Sum Block(XAB) features increasingly-recognized Meso-Neoproterozoic geological records. However, the origin, temporal-spatial distribution of ancient materials, and their roles in crust evolution remain to debate. This paper presents an integrated study of zircon U-Pb ages and Hf-O isotopes for Mesoproterozoic and Paleozoic granites from the Erenhot region of central Inner Mongolia, along eastern CAOB. The intrusion of 1450 Ma syenogranite denotes that the Precambrian basement of XAB extends from Sonid Zuoqi westward to Erenhot. The 384 and 281 Ma monzogranites containing Mesoproterozoic xenocrystic zircons possess Proterozoic-dominant two-stage Hf model ages, further suggesting the wide existence of Proterozoic crust beneath western XAB. Cyclic Proterozoic crustal growth and reworking seem to show close linkages with the orogenesis during relevant supercontinent cycles. 1450-1360 Ma juvenile crustal growth at Erenhot and synchronous ancient crust reworking at Sonid Zuoqi and Abagaqi were likely resulted from retreating subduction involved in Columbia breakup, while 1.2-1.0 Ga reworking and 0.9-0.7 Ga growth events within the Erenhot basement might respond to assembly and breakup of Rodinia, respectively. Besides, our work confirms that reworking of Neoproterozoic crust played important roles during Paleozoic multi-stage accretion of CAOB.
文摘The exposed area of igneous rocks in East Kunlun Mountains is very large and they made a magmatic arc belt broad in scale. The intrusive rocks are mainly of Hercynian—Indo\|Sinian cycle and less of Caledonian and Yanshanian cycle [1～2] . During the geological mapping of 1∶250000 of Donggeicuonahu area, we firstly found the evidence of intrusive rock of Jinning cycle. Intrusive rocks of Jinning cycle, whose exposed area is about 30km, are located in Waliaoga\|Shaxiong area among East Kunlun magmatic arc belt and are composed of two intrusive bodies. The rock types of Jinning cycle are mainly trondjemite and tonalite. Their wall rocks are Baishahe Group of Paleo\|Proterozoic and was intruded by Hercynian-Indo\|Sinian cycle granodiorite . The wall rock types are mainly banded amphibolite,biotite\|plagioclase schist,leptynite,leptite,banded marble and mica\|schist , their metamorphic condition is overall middle amphibole facies , partly granulite facies , tectonic deformation was mainly of flowage fold and flowage shear in middle and deep levers. Although intrusive rocks of Jinning cycle had undergone intensive metamorphism and deformation, they also preserve the intrusive appearance and are uniform in field. We can see intrusive contacted with wall rock or infolded the basic inclusions. Gneissosity is very common in intrusive rocks of Jinning cycle. Even though intensive metamorphism and deformation lead to interlude between intrusive body and wall rock, most wall rock exists in intrusive rocks as giant roof or inclusions in general, we can see intrusive contacted between intrusive body and wall rock locally. Intrusive rocks are hoar color, meso\|coarse grain lepido\|granoblastic texture , minerals are mainly plagioclase evidence to study the forming and evolution of orogeny of Jinning and Caledonian cycle.
文摘Deep crustal rocks of the Early Proterozoic orogenic belt (DCR)in Daqingshan area mainly included the synorogenicmetamorphic khondalite series and reworked Archeanbasement granulites. During the early stage about 1900～1800 Ma, the DCR consisted of five huge slices which obducted over and stacked up along a series of hightemperature shear zone (HTSZ), and were subsequently uplifted from the deep crustal level to the middle one accompanied with granuliteamphibolite facies retrometamorphic reworking in HTSZ. From 1800～1700 Ma, some slices and HTSZ mentioned above were oveprinted by several lowtemperature shear zone (LTSZ), of which the lowangle oblique thrusts caused these DCR to uplift again from the middle crustal level to the shallow one, and experienced retrometamorphic reworking of greenschist facies. These two stages of uplifting processes should be included in an entire Early Proterozoic orogenic cycle.
文摘The West Kunlun orogenic belt, one of the least studied areas in China, is located at the junction between the Qinghai—Tibetan Plateau and Tarim Basin and has undergone intense tectonic action and frequent magmatism.The West Kunlun orogenic belt can be divided into five tectonic\|magmatic evolution stages according to the character of the igneous rocks, metamorphic rocks, sedimentation mode, tectonic phases and isotopic ages(Fig 1).Active stages have dominated with only short intervening stable stages. This kind of evolution is not simply repeated but that a later stage is elevation and development of its former stage.Space\|time distribution of granitoids varies with each different tectonic\| magmatic stage as well as within different periods of the same tectonic\| magmatism stage. Take time into condition , It is an important turning movement of tectonics\|magmatism evolution during the Indo\|Sinian movement, as space the middle fault (Jiang Chunfa 1982) of the West Kunlun orogenic belt is a significant border o f tectonics\|magmatism evolution. Granitoids formed before Indo\|Sinian movement are mainly distributed to the north of the middle fault of West Kunlun. These granitoids are mostly granites of early and middle Proterozoic, Caledonian and Hercynian ages. A unique control on the granitoid evolution is that they become younger from NE to SW, crossing the regional structure line. Granitoids formed after Indo\|Sinian movement are mainly distributed to the south of the middle fault. But distribution of granitoids of early Yanshan cycle cut across the middle fault of West Kunlun Mountain. Their age distribution shows a bidirectional control with the granitoids becoming younger across the regional structural lines from NE and SW boundary fault to the interior of the fracture belts.
