Title: Geochemistry of the Baishitouquan Amazonite—and Topaz—bearing Granite in the Mid—Tianshan Belt,Xinjiang,China
Abstract:The Baishitouquan amazonite and topaz-bearing granite is one of the typical high-rubidium and high-fluorine granites in the eastern part of the Mid-Tianshan belt.This intrusion is in sharp contact wit...The Baishitouquan amazonite and topaz-bearing granite is one of the typical high-rubidium and high-fluorine granites in the eastern part of the Mid-Tianshan belt.This intrusion is in sharp contact with Mid-Proterozoic schists,gneisses and marbles,and is composed of four zones transitional from the bottom upwards:leucogranite,amazonite granite,topaz-bearing amazonite granite and topaz quartz albitite.The Baishitouquan granite contains highly ordered K-feldspar,Li-rich mica,Mn-rich garnet,α-quartz and low-temperature zircon and is chemically high in Si,K,Na,Al,Li,Rb,Cs an F, and low in Ti,Fe,Ca,Mg,P,Co,Ni,Cr,V,Sr and Ba,with Na2O>K2O,Amazonite from the amazonite granite zone contains 1867 ppm Rb.The F contents of bulk rocks are 3040 and 4597 for the amazonite granite and topaz-bearing amazonite granite zones,respectively,These two zones have δ^18O values of 8.97-9.85‰(SMOW)and show flat REE distribution patterns with strong Eu depletion.K-Ar and Rb-Sr ages of this inturusion are 226.6 Ma and 209.6 Ma respectively,with an initial ^87Sr/^86Sr ratio of 0.987±0.213.The Baishitouquan granite is the product of crystallization of a low-temperature,and water,rubidium and fluorine-rich magma,which may have been derived from partial melting of muscovite-rich crustal rocks.Consolidation of this granite involved two contasting and successive stages:melt crystallization and hydrothermal metasomatism and precipitation.Various geological features of this granite were formed during the transition from the magmatic to the hydrothermal stage.Read More
Publication Year: 1994
Publication Date: 1994-01-01
Language: en
Type: article
Access and Citation
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot