Climatic and tectonic controls on weathering in south China and Indochina Peninsula: Clay mineralogical and geochemical investigations from the Pearl, Red, and Mekong drainage basins

摘要: [1] Results of clay mineralogy, major element geochemistry, and Sr Nd isotopes in 93 argillaceous samples collected from drainage basins the Pearl, Red, Mekong rivers reveal different degrees chemical weathering Southeast Asia despite similar climate conditions across these regions. The kaolinite/illite ratio, illite chemistry index, crystallinity can be used as indicators intensity. These mineralogical proxies combined with K2O/(Na2O + CaO) molar index alteration (CIA), trends observed results indicate intensive silicate Pearl River basin, moderate to Red basin. Although a significant modification epsilon Nd(0) values our riverine sediments during transport is unlikely, Sr-87/Sr-86 ratios are controlled by various states high-Sr minerals such plagioclase (rich Na Ca) linear decrease trend Mekong, river basins. Our suggest that it not warm heavy monsoon precipitation but tectonics playing most role controlling erosion processes south China Indochina Peninsula. Strong physical caused tectonic activities incision along eastern margin Tibetan Plateau fault system responsible for high contents primary lowlands