铜陵狮子山地区中酸性侵入岩锆石SHRIMP U-Pb定年及岩浆作用的深部过程  

Zircon SHRIMP U-Pb dating of intermediate-acid intrusive rocks from Shizishan,Tongling and the deep processes of magmatism

作　　者：吴才来[1] 董树文[2] 国和平 郭祥炎 高前明 刘良根[3] 陈其龙[1] 雷敏[1] WOODENJ L MAZADAB FK MATTINSON C 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质科学院,北京100037 [3]安徽地矿局321地质队,铜陵244033 [4]美国斯坦福大学,加里佛尼亚斯坦福94305

出　　处：《岩石学报》2008年第8期1801-1812,共12页Acta Petrologica Sinica

基　　金：国家财政部专项-矿产资源深部探测实验(140102);国家自然科学基金项目(49772106;40472034;40672049);中国地质调查局地质调查项目(1212010611803)资助

摘　　要：铜陵狮子山地区中酸性侵入岩锆石 SHRIMP U-Pb 定年结果表明,白茫山辉石二长闪长岩、鸡冠山和大团山石英二长闪长岩以及胡村花岗闪长岩的年龄分别为:138.21±0.82Ma、139.9±1.1Ma、139.3±1.2Ma 和140.9±1.2Ma。岩浆侵位顺序为花岗闪长岩→石英二长闪长岩→辉石二长闪长岩。根据锆石 SHRIMP U-Pb 年龄变化范围,推测该区岩浆活动持续的时间约为15Ma,且岩浆属脉动式多次侵位,后期岩浆侵位的热使早期岩体中已结晶的锆石发生熔解、重结晶,形成新的锆石。地下深部岩浆活动频繁,形成了多级岩浆房,使得本区的莫霍面界线不明显。Zircon SHRIMP dating of intermediate-acid intrusive rocks from Shizishan, Tongling shows that the ages of these rocks are ranged from 138. 21 ± 0. 82Ma to 140. 9 ± 1.2Ma with Baimanshan pyroxene monzodiorite, Jiguanshan and Datuanshan quartz monzodiorite,and Huchen granodiorite being 138.21 ±0. 82Ma,139.9 ± 1.1Ma,139. 3 ± 1.2Ma and 140.9 ± 1.2Ma,respectively. The orders of intrusion from early to late are granodiorite→quartz monzodiorite →pyroxen monzodiorite. Based on the range of zircon SHRIMP ages, we infered that the magmatic intrusive activity with multi-orders and pulsation lasted about 15Ma. During the magmatic intrusion, the heat from the late intrusive made the zircons in the early intrusive body melt and recrystallize, forming new zircons with a younger age. Multi-magma reservoirs with different depth undergrounded are resulted from the deep multi-magama activity, which made the Moho borderline between crust and mantle not be clear.

关 键 词：中酸性侵入岩 锆石SHRIMP U—Pb定年 狮子山 铜陵 

分 类 号：P588.121[天文地球—岩石学] P597.3[天文地球—地质学]