陕西绥德地区黄土-古土壤序列地球化学特征及其环境指示意义

黄土高原北部的绥德地区处于干旱-半干旱地区,对环境变化的响应十分敏感,通过对黄土-古土壤的研究对比可以探索该区的古环境气候特征、环境变化信息等相关问题.本文对绥德黄土-古土壤进行常量、微量、稀土元素测试分析,并与其他地区黄土的地球化学特征进行了对比.结果 表明:绥德地区黄土-古土壤的主要化学成分以SiO2、Al2O3、...

Geochemical Characteristics of Loess Paleosol Sequence and Its Environmental Implications in Suide Area, Shaanxi

The Suide area in the northern part of the Loess Plateau is in an arid/semi-arid area. It is very sensitive to the environmental changes. By comparing the loess paleosol, we can explore the characteristics of the paleoclimate, climate change and other related issues in the area. In this paper, the major, trace and rare earth elements of Suide loess-paleosol are tested and analyzed, and the geochemical characteristics of loess in other areas are compared. The results show that:the main chemical components of loess-paleosol in Suide area are SiO₂, Al₂O₃, Fe₂O₃ and CaO. The geochemical parameters related to weathering degree, pedogenesis intensity and various climatic substitution indexes indicate that most of Suide loess was in the low weathering stage of dry and cold climate. Only S₂ paleosol formation stage has strong pedogenesis, moderate weathering degree and the most precipitation, which was in a temporary warm and semi humid climate. The sequence of weathering intensity and pedogenesis is S₂ > S₃ > S₄ > S₁ > L₄ > L₃ > L₂ > L₁. The provenance indicator parameters show that the provenance of Suide Loess-Paleosol is different from that of other loess in Loess Plateau. Tengger Desert, Badain Jaran Desert and Mu Us Desert in Alxa Plateau and Ordos Plateau may be the main provenance areas.