A volcano-platform carbonate sequence ,from Carboniferous to Permian , is widely trapped in the deep water deposits in Changning- Menglian belt .Three components can be roughly recognized in ascending order as :the la...A volcano-platform carbonate sequence ,from Carboniferous to Permian , is widely trapped in the deep water deposits in Changning- Menglian belt .Three components can be roughly recognized in ascending order as :the lava .the volcaniclastic and carbonate rocks .In most cases, the sequence is incomplete due to faulting resulted from the strong orogenic compression. But (he stratigraphic succession is continuous except for the two interruptions of paleokarsts . which extended from middle Late Carboniferous to Late Permian and from late Early Permian to Late Permian respectively .A preliminary study indicates that the stratigraphy, petrology , sedimentation , vokanism geochemistry and fossils in the sequence are quite similar to mat in modern and ancient oceanic islands and there may be the relics of ancient oceanic islands in the paleo-Tethys .The differences among these sequences probably suggest a complex configuration of the islands or island chain These islands were formed under infra oceanic environments of the paleo-Tethys ,far from continent and accreted to Simao continental margin in Late Permian .The occurrence of large number of ancient oceanic islands in orogenic belts , including the paleo Tethys, Cordillera , etc ..suggests mat some ancient oceans .such as the paleo Tethys and proto-Pacific ,were full of archipelagoes as their modem counterparts . It is possible that more oceanic islands will be recongnized when sufficient research is done in orogenic belts over the world .展开更多
There has been a long\|term debate about the Paleo\|Tethyan Ocean in South China continent. Based on the geological and geochemical studies, it is suggested that there exist two tectonic belts in SE Yunnan, SW China c...There has been a long\|term debate about the Paleo\|Tethyan Ocean in South China continent. Based on the geological and geochemical studies, it is suggested that there exist two tectonic belts in SE Yunnan, SW China called Ailao Shan zone and Shizong—Mile zone, which separate Yangtze Block, Cathysian Block and Indo\|China Block from each other. The evolutionary history and its geodynamics of these suture zones are correlated with the Paleo\|Tethyan Ocean. Both of the zones are keys to understanding whether the Paleo\|Tethyan Ocean extended from Western Yunnan area to east of the South China continent. The Ailao Shan belt consists of Red River fault, Ailao Shan fault, Shuanggou fault and Huashan—Yayi fault, which are the boundaries of the Ailao Shan basement metamorphic belt, ophiolitic melange belt and Island\|arc volcanic\|sediments belt, respectively.The ophiolitic melange belt is characterized by the existence of the ophiolite in Shuanggou area, which represents the relicts of the oceanic crust of the Ailao Shan Ocean. In addition, there exist volcanic rocks in west of the ophiolitic melange belt in Jingdong area. The geochemical characteristics of basalts in Jingdong are similar to that of the E\|MORB. Synthesized studies on geochemistry and tectonics suggest that the basalts in Jingdong area were formed in an extensional rift setting in Devonian.展开更多
The Kunlun Mountains is situated in the north margin of the Tibetan plateau and is one of crucial areas for unraveling the tectonic evolutionary history of the plateau and Eurasia. However, there is no widely accepted...The Kunlun Mountains is situated in the north margin of the Tibetan plateau and is one of crucial areas for unraveling the tectonic evolutionary history of the plateau and Eurasia. However, there is no widely accepted model for this area. One of the reasons is that some basic issues for the tectonic reconstruction have not been well settled, they are: (1) Is the Kunlun Mountains an ancient accretion prism, or a mini continent with old basement?(2) What is the age of the Kudi ophiolite, early Paleozoic or late Paleozoic?(3) When did the South Kunlun Block accrete to the Tarim Block?(4) Do the fifth and the forth sutures represent different oceans, or they are just the chronologically different relics of the same ocean?(5) Did the Kunlun Mountains experience continuous subduction since Neoproterozoic?(6) When did the Paleo\|Tethys closed in the West Kunlun range?展开更多
基金The research is supported by National Nature Science Foundation of China No.49172101the State Education Committee Funds for Doctoral Supervisors
文摘A volcano-platform carbonate sequence ,from Carboniferous to Permian , is widely trapped in the deep water deposits in Changning- Menglian belt .Three components can be roughly recognized in ascending order as :the lava .the volcaniclastic and carbonate rocks .In most cases, the sequence is incomplete due to faulting resulted from the strong orogenic compression. But (he stratigraphic succession is continuous except for the two interruptions of paleokarsts . which extended from middle Late Carboniferous to Late Permian and from late Early Permian to Late Permian respectively .A preliminary study indicates that the stratigraphy, petrology , sedimentation , vokanism geochemistry and fossils in the sequence are quite similar to mat in modern and ancient oceanic islands and there may be the relics of ancient oceanic islands in the paleo-Tethys .The differences among these sequences probably suggest a complex configuration of the islands or island chain These islands were formed under infra oceanic environments of the paleo-Tethys ,far from continent and accreted to Simao continental margin in Late Permian .The occurrence of large number of ancient oceanic islands in orogenic belts , including the paleo Tethys, Cordillera , etc ..suggests mat some ancient oceans .such as the paleo Tethys and proto-Pacific ,were full of archipelagoes as their modem counterparts . It is possible that more oceanic islands will be recongnized when sufficient research is done in orogenic belts over the world .
文摘There has been a long\|term debate about the Paleo\|Tethyan Ocean in South China continent. Based on the geological and geochemical studies, it is suggested that there exist two tectonic belts in SE Yunnan, SW China called Ailao Shan zone and Shizong—Mile zone, which separate Yangtze Block, Cathysian Block and Indo\|China Block from each other. The evolutionary history and its geodynamics of these suture zones are correlated with the Paleo\|Tethyan Ocean. Both of the zones are keys to understanding whether the Paleo\|Tethyan Ocean extended from Western Yunnan area to east of the South China continent. The Ailao Shan belt consists of Red River fault, Ailao Shan fault, Shuanggou fault and Huashan—Yayi fault, which are the boundaries of the Ailao Shan basement metamorphic belt, ophiolitic melange belt and Island\|arc volcanic\|sediments belt, respectively.The ophiolitic melange belt is characterized by the existence of the ophiolite in Shuanggou area, which represents the relicts of the oceanic crust of the Ailao Shan Ocean. In addition, there exist volcanic rocks in west of the ophiolitic melange belt in Jingdong area. The geochemical characteristics of basalts in Jingdong are similar to that of the E\|MORB. Synthesized studies on geochemistry and tectonics suggest that the basalts in Jingdong area were formed in an extensional rift setting in Devonian.
文摘The Kunlun Mountains is situated in the north margin of the Tibetan plateau and is one of crucial areas for unraveling the tectonic evolutionary history of the plateau and Eurasia. However, there is no widely accepted model for this area. One of the reasons is that some basic issues for the tectonic reconstruction have not been well settled, they are: (1) Is the Kunlun Mountains an ancient accretion prism, or a mini continent with old basement?(2) What is the age of the Kudi ophiolite, early Paleozoic or late Paleozoic?(3) When did the South Kunlun Block accrete to the Tarim Block?(4) Do the fifth and the forth sutures represent different oceans, or they are just the chronologically different relics of the same ocean?(5) Did the Kunlun Mountains experience continuous subduction since Neoproterozoic?(6) When did the Paleo\|Tethys closed in the West Kunlun range?
