The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only a...The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only as a good age indicator for the geomorphic surfaces but also coats themselves can be directly used as dating materials in the ESR method. Through measuring the thickness of carbonate coats on stones in soils on the alluvial terraces in the mouth of the Heishanxia gorge of the Yellow River and ESR dating of layers separated from the carbonate coats, the average of accumulation rates of the thickness of carbonate coats on stones since 1.57 Ma was calculated to be 0.10 mm/ka in the studied area, and a regression equation between carbonate coat thickness and age was also generated. From these research results, ages of T2-T11 terraces of the Yellow River in the studied area were systematically determined, and their values are in turn 18 ka, 94 ka, 139 ka, 215 ka, 305 ka, 410 ka, 495 ka, 742 ka,展开更多
The financial turbulence caused by the U.S.subprime crisis has a far-reaching impact on the global financial system and economic development.Based on an in-depth analysis of the cause of U.S.subprime crisis and its ef...The financial turbulence caused by the U.S.subprime crisis has a far-reaching impact on the global financial system and economic development.Based on an in-depth analysis of the cause of U.S.subprime crisis and its effects on China and global economy,in combi-nation with the current status of China's telecom sector,this article puts forward policy suggestions for the de-velopment and regulation of China's telecom sector.展开更多
基金This work was supportedby the National Natural Science Foundation of China (Grant No. 49732095)Joint Foundation of Earthquake Science (Grant Nos. 197021 and 9507422)and the State Major Basic Research Development Plan (Grant No. 95130102).
文摘The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only as a good age indicator for the geomorphic surfaces but also coats themselves can be directly used as dating materials in the ESR method. Through measuring the thickness of carbonate coats on stones in soils on the alluvial terraces in the mouth of the Heishanxia gorge of the Yellow River and ESR dating of layers separated from the carbonate coats, the average of accumulation rates of the thickness of carbonate coats on stones since 1.57 Ma was calculated to be 0.10 mm/ka in the studied area, and a regression equation between carbonate coat thickness and age was also generated. From these research results, ages of T2-T11 terraces of the Yellow River in the studied area were systematically determined, and their values are in turn 18 ka, 94 ka, 139 ka, 215 ka, 305 ka, 410 ka, 495 ka, 742 ka,
文摘The financial turbulence caused by the U.S.subprime crisis has a far-reaching impact on the global financial system and economic development.Based on an in-depth analysis of the cause of U.S.subprime crisis and its effects on China and global economy,in combi-nation with the current status of China's telecom sector,this article puts forward policy suggestions for the de-velopment and regulation of China's telecom sector.
