东疆星星峡地区白石头泉高铷氟花岗岩的特征和成因  

GEOLOGY AND GENESIS OF THE BAISHITOUQUAN HIGH-RUBIDIUM AND FLUORINE GRANITES IN THE XINGXINGSHIA DISTRICT OF HAMI COUNTY, XINJIANG

作　　者：顾连兴[1] 杨浩[1] 苟晓琴[1] 郭继春[1] 王金珠 

机构地区：[1]南京大学地球科学系,新疆地矿局第六地质大队

出　　处：《岩石学报》1994年第1期41-53,共13页Acta Petrologica Sinica

基　　金：国家攻关新疆305项目

摘　　要：新疆哈密白石头泉高铷氟花岗岩体自中心往顶部可分为：淡色花岗岩、天河石花岗岩、黄玉天河石花岗岩和黄玉石英钠长岩等岩相。各岩相之间在矿物成分和结构构造上有着系统的变化。岩体的岩浆可能来自于挤压背景下富含泥质的地槽沉积物的超变质和部分熔融。其成岩作用包括了熔体中的直接结晶和岩浆晚期－期后热液的交代两个过程。高含量的氟对于岩浆的演化起着重要作用。The Baishitouquan granite is typical of the high-rubidium and fluorine granites in the Xingxingxia district of Hami County, Xinjiang Province. 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, Q-quartz and low-temperature zircon and is chemically high in Si, K, Na, Al, Li, Rb, Cs and F, and low in Ti, Fe, Ca, Mg, P, Co, Ni, Cr, V, Sr, Ba, with Na2O＞K2O.Amazonnes from the amazonite granite zone contain 1867μg/g Rb. Bulk rock F contents are 3042 and 4597μg/g for the amazonite granite and topaz-bearing amazonite granite zones, respectively. These two zones have δ18O values of 8. 97～9. 85 per mil (SMOW) and have flat REE distribution patterns with strong europium depletion. K-Ar and Rb-Sr ages of this intrusion are 226. 6Ma and 209. 6Ma, respectively, with an initial 87Sr/86Sr ratio of 0. 987±0.213.The Baishitoouquan granite is the product of crystallization of a low-temperature, and water-, rubidium- and fluorine-rich magma, which may have been resulted from partial melting of muscovite-rich crustal rocks. Solidification of this granite includes two contrasting and successive stages: melt crystallization and hydrothermal metasomatism and precipitation. Various geological features of this granite were formed during the transition from magmaticto hydrothermal stages.

关 键 词：花岗岩 铷 氟 天河石 新疆 

分 类 号：P588.121[天文地球—岩石学]