Geochemistry of the Baishitouquan Amazonite-and Topaz-bearing Granite in the Mid-Tianshan Belt, Xinjiang, China  

作　　者：顾连兴 杨浩 苟晓琴 郭继春 王金珠 

出　　处：《Chinese Journal Of Geochemistry》1994年第4期289-304,共16页中国地球化学学报

摘　　要：The Baishitouopan amaznito and topazbearing granite is one of the typical high-rubidium andhigh-fluorine granites in the eastern paft of the Mid-Tianshan belt. This intrusion is in sharp contactwith Mid-Proterozoic schists, gneisses and marbles, and is compond of four zones transihonal fromthe bottom upwards: leucogranite, amazonite granite, topaz-bearing amazonite granite and topazquartz albitite.The Baishitouquan granite contains highly ordered K-feldspar, Li-rich mica, Mn-rich gamet,a-quartz and low-temerature rircon and is chemically high in Si, K, Na, Al, Li, Rb, Cs and F,and low in Ti, Fe, Ch, Mg, P, Ch, Ni, Cr, V, Sr and Ba, with Na2O>K2O. Amazonite fromthe amazonite granite zone contains 1867 ppm Rb. The F contents of bulk rocks are 3040 and4597 for the amazonite granite and topazbearing amazonite granite zones, respectivel. These twozones have δ18O values of 8.97 - 9.85%, (SMOW) and show flat REE distribution patterns withstrong Eu depletion. KAr and Rb-Sr ages of this intrusion are 226. 6 Ma and 209. 6 Marespectively, with an initial 87Sr/86Sr ratio of 0.987±0.213.The Baishitouquan granite is the product of crystallization of a lowtemperature, and wther,rubidium. and fluorine-rich magma , which may have been derived from partial melting ofmuscoviterich crustal rocks. Consolidation of this granite involved two contrasting and successivestagst melt crystallization and hydrothermal metasomasm and pforitation. Various geological features of this granite were formed during the transition from the magmatic to the hydrothermal stage.The Baishitouopan amaznito and topazbearing granite is one of the typical high-rubidium andhigh-fluorine granites in the eastern paft of the Mid-Tianshan belt. This intrusion is in sharp contactwith Mid-Proterozoic schists, gneisses and marbles, and is compond of four zones transihonal fromthe bottom upwards: leucogranite, amazonite granite, topaz-bearing amazonite granite and topazquartz albitite.The Baishitouquan granite contains highly ordered K-feldspar, Li-rich mica, Mn-rich gamet,a-quartz and low-temerature rircon and is chemically high in Si, K, Na, Al, Li, Rb, Cs and F,and low in Ti, Fe, Ch, Mg, P, Ch, Ni, Cr, V, Sr and Ba, with Na2O>K2O. Amazonite fromthe amazonite granite zone contains 1867 ppm Rb. The F contents of bulk rocks are 3040 and4597 for the amazonite granite and topazbearing amazonite granite zones, respectivel. These twozones have δ18O values of 8.97 - 9.85%, (SMOW) and show flat REE distribution patterns withstrong Eu depletion. KAr and Rb-Sr ages of this intrusion are 226. 6 Ma and 209. 6 Marespectively, with an initial 87Sr/86Sr ratio of 0.987±0.213.The Baishitouquan granite is the product of crystallization of a lowtemperature, and wther,rubidium. and fluorine-rich magma , which may have been derived from partial melting ofmuscoviterich crustal rocks. Consolidation of this granite involved two contrasting and successivestagst melt crystallization and hydrothermal metasomasm and pforitation. Various geological features of this granite were formed during the transition from the magmatic to the hydrothermal stage.

关 键 词：绿长石 黄玉 花岗岩 铷 氟 新疆 天山地区 地球化学 氧同位素 锶同位素 

分 类 号：P588.121[天文地球—岩石学] P597[天文地球—地质学]