Enrichment and Loss of Trace Elements in Biotite in Weathering Crust of Granite in Warm Temperate Zone

Biotite is one of the minor minerals in granite and easy to weather. This article takes biotite in the weathering crust of Yuangezhuang pluton as the research object, and analyzes the changes of the enrichment and loss of trace elements in the weathering crust. The purpose is to understand the response of biotite to the weathering of warm-temperate granite host rock and the exclusive in-fluence of specific minerals on the earth’s surface chemical process. The results showed that the biotite in this weathered crust is rich in elements Ba, Zn, Rb, Zr, Li, V, Cr, Sr, Nb, Ni, and is poor in Cd, Mo, Tl, Ge, Ta, Be, W, U, Hf and other elements. The loss rate of biotite trace elements in the-weathered crust is Ba > Rb > Li > Co > Cs > V > Ge > Ni > Cr > Nb > Sc, and the enrichment rate Sr > Pb > Th > Be > Cd > Ga. The loss rate of large ion elements Ba, Rb, Cs is higher and the loss rate of iron-philic elements Co, V, Ni, Cr, Sc, Ge is secondary; Sr enrichment rate is much higher than other elements; concentration rate of Pb 、 Cu 、 Cd chalcophile element reaches maximum when weathering is strongest. The element migration/enrichment rate reaches the maximum in the sub-surface layer, and the change trend is different at the top and lower layers; The ratio of trace elements of Rb/Sr, Li/Sc, Rb/Cs, Ba/Sr showed a steady decreasing trend with the deepening of the weathering process in weathering crust, which can be used as an effective index for determining the degree of weathering of biotite. The content of rare earth elements is strongly enriched in the surface layer, and the content is high. The Ce group elements are the main elements, but the light rare earth enrichment has a large difference in some parts. Both Ce and Eu elements have profit and loss changes, and the overall performance is slightly deficient.