Based on electron probe analyses of the minerals and bulk composition of the Cenozoic volcanic rocks from Yumen and Hoh Xil lithodistricts, Qinghai\|Xizang plateau, the forming conditions including the temperature and...Based on electron probe analyses of the minerals and bulk composition of the Cenozoic volcanic rocks from Yumen and Hoh Xil lithodistricts, Qinghai\|Xizang plateau, the forming conditions including the temperature and pressure of those rocks are studied in this paper. According to the thermodynamic calculation results of mineral\|melt equilibrium, the depth of the asthenosphere superface (about 75-130 km) for the northern part of the Qinghai\|Xizang plateau during the Cenozoic is suggested. Finally, this paper indicates that the Cenozoic volcanic rocks in the northern part of the Qinghai\|Xizang plateau mainly consist of shoshonite series. Their forming temperature is 630-1039℃ and forming pressure is between 2.3-4.0 GPa. The rocks were formed in the intracontinental orogenic belt, of which the primary magma was originated from a particular enrichment upper mantle and accreted crust\|mantle belt or directly from asthenospheric superface as a result of partial melting of pyrolite.展开更多
The zoning' boundaries of permafrost are theoretically determined fromthe relation between permafrost and modern climate in this paper. The boundary elevations are given in a profile. There are many phenomena demo...The zoning' boundaries of permafrost are theoretically determined fromthe relation between permafrost and modern climate in this paper. The boundary elevations are given in a profile. There are many phenomena demonstrating a commondegeneration, such as buried frozen soil, pseudo--permafrost land forms,variations ofpatchy permafrost table, multigelation, and vegetation changing in different regions.The important conclusion is that a basic trend of the permafrost changing in theplateau is degeneration.展开更多
In our work, ocean ridge granite, i.e., Oytag plagiogranite massif, was discovered in western Qinghai\|Xizang plateau. It intruded into the basic lava of the Oytag ophiolite suite and it was formed a little later than...In our work, ocean ridge granite, i.e., Oytag plagiogranite massif, was discovered in western Qinghai\|Xizang plateau. It intruded into the basic lava of the Oytag ophiolite suite and it was formed a little later than the (ultra) mafic rocks of the Oytag ophiolite suite. The Oytag plagiogranite possesses the geochemical characteristics of mantle\|source granite and was formed in the \!supra\|subduction zone" (SSZ) ocean ridge environment, like the ocean ridge granite of Troodos, Cypus.展开更多
基金中国地质调查局资助的基础研究项目(编号:12120113093800)的成果supported by the U.S. Department of Energy through contract DE-AC52-06NA25396 to Los Alamos National Laboratory~~
基金TheprojectwassupportedbytheNationalNaturalScienceFoundationofChina! (No .492 34 0 80 ) theGeologicalSectionalFoundationofMGM
文摘Based on electron probe analyses of the minerals and bulk composition of the Cenozoic volcanic rocks from Yumen and Hoh Xil lithodistricts, Qinghai\|Xizang plateau, the forming conditions including the temperature and pressure of those rocks are studied in this paper. According to the thermodynamic calculation results of mineral\|melt equilibrium, the depth of the asthenosphere superface (about 75-130 km) for the northern part of the Qinghai\|Xizang plateau during the Cenozoic is suggested. Finally, this paper indicates that the Cenozoic volcanic rocks in the northern part of the Qinghai\|Xizang plateau mainly consist of shoshonite series. Their forming temperature is 630-1039℃ and forming pressure is between 2.3-4.0 GPa. The rocks were formed in the intracontinental orogenic belt, of which the primary magma was originated from a particular enrichment upper mantle and accreted crust\|mantle belt or directly from asthenospheric superface as a result of partial melting of pyrolite.
文摘The zoning' boundaries of permafrost are theoretically determined fromthe relation between permafrost and modern climate in this paper. The boundary elevations are given in a profile. There are many phenomena demonstrating a commondegeneration, such as buried frozen soil, pseudo--permafrost land forms,variations ofpatchy permafrost table, multigelation, and vegetation changing in different regions.The important conclusion is that a basic trend of the permafrost changing in theplateau is degeneration.
文摘In our work, ocean ridge granite, i.e., Oytag plagiogranite massif, was discovered in western Qinghai\|Xizang plateau. It intruded into the basic lava of the Oytag ophiolite suite and it was formed a little later than the (ultra) mafic rocks of the Oytag ophiolite suite. The Oytag plagiogranite possesses the geochemical characteristics of mantle\|source granite and was formed in the \!supra\|subduction zone" (SSZ) ocean ridge environment, like the ocean ridge granite of Troodos, Cypus.
