作　　者： ; ;

机构地区： 中国科学院广州地球化学研究所

出　　处： 《中山大学学报论丛》 1997年第5期68-71,共4页

摘　　要： 扫描电镜观测表明，青藏高原古岩溶风化壳红土中石英砂的表面结构特征以化学作用形成的为主，机械作用形成的为辅，反映了这类红土的长期残留特征，对应着风化壳红土发育时期，亦即高原晚第三纪古岩溶发育期的湿热气候．部分经过后期搬运的样品，表面机械作用形成的结构特征变得明显，反映了高原的后期抬升所引起的干寒气候条件．从表面结构的时间演化序列看，多数样品表现为化学结构上面叠加了机械结构，但也有在机械结构上面叠加化学结构的，这反映了自晚第三纪以来青藏高原环境变化的复杂性。 The quartz grain surface textures observed under the scanning electrical microscope (SEM) of laterites in Tibetan paleokarst area are composed mainly of chemically produced features, and secondary of mechanically produced features, which reflected that the kind of laterites were formed in a long term period of humid tropical chemical weathering, i.e., the period of Neogene paleokarst of the plateau. The mechanically produced features are in the majority in surface textures of some samples taken place remarkable movement by various geomorphologic processes which were driven by the uplift of the plateau, those samples such as slope wash and alluvial deposit derived from laterites. In many of the samples the evolution pattern in time of the quartz grain surface textures display that the chemicall produced features were overlaid by mechanically produced ones, on the other hand, a few samples go in the opposite direction, the mechanically produced features were overlaid by chemically produced ones, which reflect the property of polycycle and complex of the Tibetan environmental evolution since Neogene. 

关 键 词： 青藏高原 石英砂颗粒表面结构 电镜扫描 古岩溶 红土

领　　域： [文化科学] [文化科学]