Preliminary Study On The Nature And Development Process Of Surface Calcretes In The Hinterland Of Qinghai-Tibet Plateau

Calcretes are common supergene deposits in arid and semi-arid regions,and are important carriers for recording the interaction information of the earth's multi-layer layers.The in-depth study of their characteristics and development history will help to understand the formation and evolution history of regional landforms.In this paper,the structure and chemical composition of the calcrete at the bottom of the gravel on the top of the two-level platform at the eastern foot of the Shuanghu Xiyaer Mound platform in northern Tibet are studied by microscopic observation and micro-element analysis.The topic selection has important theoretical significance and practical value.The paper has made the following progress:(1)The analysis of the microstructure shows that calcretes generally have a laminar structure that grows downward,indicating changes in the deposition process and environmental conditions.(2)The analysis of micro-region elements shows that the growth curve of chemical elements in calcretes can be traced laterally and has a certain degree of stability;the degree of stability is related to the layer(depth)and the shape of the bottom surface of the gravel.(3)The comparison with the known environmental change records shows that the growth curve of calcretes in the study area has a good correspondence with the climate change records.The study of different scales and different experimental methods of calcretes in this article provides new methods and experimental materials for studying the properties and development process of calcretes on the hinterland of the Qinghai-Tibet Plateau.The selection and research methods of different scales of calcretes data are also useful for the study of calcretes related properties and development mechanisms in other regions.In this paper,the study of the calcretes at different scales and different experimental methods provides new methods and datas for the study of the characteristics and development process of the calcrete in the hinterland of the Tibetan Plateau.The selection and research methods of the calcrete data at different scales are also useful for the study of the related properties and development mechanisms of calcium scales in other regions.