福建同安角闪辉长岩的矿物化学、^(40)Ar-^(39)Ar年龄及地质意义  

Mineral Chemistry and ^(40)Ar-^(39)Ar Ages of Hornblende Gabbro from Tong'an,Fujian Province and Their Geological Significance

作　　者：陈荣[1] 周金城[1] 

机构地区：[1]南京大学地球科学系

出　　处：《地质论评》2001年第6期602-607,共6页Geological Review

基　　金：国家自然科学基金(编号49572098;49632080)

摘　　要：福建同安角闪辉长岩的岩石化学成分具有低MgO高铝玄武岩的特征,其中的角闪石是富钙钙镁闪石,斜长石是An=91～95的钙长石。在基性的弧岩浆中,低MgO高铝玄武岩浆富水是导致结晶出高钙斜长石的关键因素。钙镁闪石的^(40)Ar-^(39)Ar年龄为129.62±0.15Ma,说明同安角闪辉长岩是东南沿海早白垩世“初始引张阶段”岩浆活动的产物。Petrochemistry of hornblende gabbro from Tong' an of Fujian Province shows typical characteristics of low-MgO and high-alumina basalts. The amphibole in it is calcium-rich tschermakitic hornblende and the plagioclases in it are anorthites (An =91 - 95 ). In basic arc magmas, the high content of H2O content of the low-MgO and high-alumina basaltic magmas leads to crystallization of high-calcium plagioclase. The 40Ar-39Ar age of the tschermakitic hornblende is 129. 620?. 152 Ma. It suggests that hornblende gabbro from Tong'an is the product of magmatic activities of 'early extensional stage' during the early Cretaceous in the southeastern coast of China.

关 键 词：^40AR-^39AR年龄 矿物化学 氩同位素 角闪辉长岩 福建 早白世 岩浆活动 

分 类 号：P588.124[天文地球—岩石学]