青藏高原东部金沙江流域盆地陆地风化特征

Continental weathering features in the Jinsha River drainage basin in the eastern part of the Qinghai-Xizang Plateau

关键词:  金沙江  流域盆地  陆地风化  青藏高原

Key words:  Jinsha River  drainage basin  continental weathering  Qinghai-Xizang Plateau

摘要:

青藏高原东部金沙江流域是研究高原隆升与陆地风化的理想地区。本文通过对金沙江河流系统的取样,从河流溶质载荷主要离子和悬浮载荷粘土矿物等方面揭示青藏高原东部金沙江流域盆地陆地风化特征。研究表明,金沙江流域盆地陆地岩石风化主要是碳酸盐岩、蒸发盐岩和硅酸盐岩。利用Si、Si/TZ^+*、Si/Na^*+K和Si/K以及(Na^*+K)/TZ⁺等5个指标结合流域区域岩石分布和土壤特征揭示出流域硅酸盐岩为浅表性初级风化,风化产物主要是富含阳离子的次生粘土矿物。

Abstract:

The Jinsha River drainage basin in the eastern part of the Qinghai-Xizang Plateau is interpreted as an ideal area for the study of the relationship between the Plateau uplift and continental weathering.The emphasis in the present paper is placed on the continental weathering features in the Jinsha River drainage basin based on the major ions in the dissolved loads and clay minerals as suspended loads.The results of research in this study show that the weathered rocks are significantly composed of carbonate rocks,evaporites and silicate rocks in the Jinsha River drainage basin.Five indexes such as Si,Si/TZ^+*,Si/(Na^*+K),Si/K and(Na^*+K)/TZ⁺ for the dissolved loads,in combination with rock distribution and soil features,have disclosed that the weathering of the silicate rocks is generally in the superficial weathering stage,with the secondary cations-rich clay minerals as the weathering products.