安徽铜陵地区中酸性侵入岩及其岩石包体中的矿物包裹体研究

MINERAL INCLUSION STUDIES OF THE INTERMEDIATE- ACID INTRUSIVE ROCKS AND THEIR ROCK ENCLAVES IN TONGLING AREA, ANHUI PROVINCE

铜陵地区是长江中、下游铁、铜、硫、金成矿带的重要组成部分。笔者对铜陵地区中酸性侵入岩及其岩石包体中的包裹体进行了较系统的岩相学、显微测温和激光拉曼光谱研究。通过岩相学观察发现了 3类包裹体 ,即晶质熔融包裹体、流体熔融包裹体和流体包裹体。显微测温资料表明 ,本区的岩浆流体成矿演化可分为 3个阶段 :岩浆阶段 ( >12 5 0～ 90 0℃± )、过渡岩浆阶段 ( 90 0～ 75 0℃± )和岩浆期后热液阶段 ( <75 0℃ )。部分熔浆的温度之高 (可达 12 5 0℃ ) ,表明其可能是底侵幔源岩浆同熔下地壳形成的。在老庙基岩体、小铜官山岩体、鸡冠石岩体和小陶家岩体中产有晶质熔融包裹体、流体熔融包裹体和流体包裹体这 3种包裹体 ,表明相应的岩浆流体演化具有连续性、继承性和阶段性 ,其对应的成矿溶液以岩浆热液为主 ;与此不同的是 ,在鸡冠山岩体和白芒山岩体中仅产有晶质熔融包裹体和流体包裹体两种类型的包裹体 ,表明相应的岩浆流体演化不具连续性 ,其对应的成矿溶液以天水热液为主。此外 ,在小铜官山岩体和鸡冠石岩体的中酸性侵入岩中 ,发现了不混溶包裹体 ,其可能是在压力释放条件下形成的。

The Tongling area is an important segment within the iron,copper,sulfur and gold ore\|forming belt along the middle\|lower Yangtze River reaches The petrographic,microthermometric and laser Raman spectroscopic studies have been systematically carried out on the inclusions from the intermediate\|acid intrusive rocks and their rock enclaves in Tongling area,Anhui Province Three types of inclusions,i e , crystalline melt inclusion,fluid\|melt inclusion and fluid inclusion have been found in these rocks and enclaves The microthermometric data show that the process of magma\|fluid\|mineralization evolution in this area can be divided into following three stages:the magmatic stage with temperature ranging from 900℃± to >1250℃, the transitional magmatic stage with temperature varying from 750℃± to 900℃ and the post\|magmatic hydrothermal stage with temperature less than 750℃ A part of melt is so high in temperature(about 1250℃)that it might be formed by syntaxis of underplated mantle magma with lower crust The crystalline melt inclusion,fluid\|melt inclusion and fluid inclusion in the Laomiaoji, Xiaotongguanshan,Jiguanshi and Xiaotaojia plutons have been examined,which indicates that the process of their corresponding magma\|fluid evolution is characteristic of continuity,inheritance and intermission and their corresponding metallogenic fluid is dominated by magmatic fluid In contrast,the crystalline melt inclusion and fluid inclusion in the Jiguanshan and Baimangshan plutons have been found, which shows that the process of their corresponding magma\|fluid evolution is not characteristic of continuity and their corresponding metallogenic fluid is dominated by meteoric fluid In addition,the immiscible inclusions have been found in the intermediate\|acid intrusive rocks of Xiaotongguanshan and Jiguanshi plutons and probably formed under the condition of pressure releasing