澳大利亚高勒克拉通约克半岛Moonta-Wallaroo矿集区北部Hiltaba岩套锆石U-Pb年龄和微量元素地球化学特征  

Zircon U-Pb geochronology and trace elements geochemistry of Hiltaba Suite in the north of Moonta-Wallaroo mining district,Yorke Peninsula,Gawler Craton,Australia

作　　者：赵宇浩[1] 姚仲友[1] 王天刚[1] 朱意萍[1] 赵晓丹[1] 姜瀚涛 ZHAO Yuhao;YAO Zhongyou;WANG Tiangang;ZHU Yiping;ZHAO Xiaodan;JIANG Hantao(Nanjing Center,China Geological Survey,Nanjing 210016,Jiangsu,China)

机构地区：[1]中国地质调查局南京地质调查中心,江苏南京210016

出　　处：《地质通报》2021年第12期2167-2178,共12页Geological Bulletin of China

基　　金：中国地质调查局项目《拉丁美洲-大洋洲大型铜镍锂资源基地评价》(编号:DD20190441);《海上丝绸之路大洋洲和南美洲矿产资源潜力评价》(编号:DD20160110)。

摘　　要：澳大利亚南澳州高勒克拉通广泛发育的Hiltaba岩套与该地区的铁氧化物铜金矿床关系密切,查明该岩套的成岩时代、成岩温度及构造背景,对铁氧化物铜金矿床的研究至关重要。对约克半岛Moonta-Wallaroo矿集区北部的眼球状花岗岩进行锆石U-Pb测年,测得年龄为1589±43 Ma,与前人确定的Hiltaba岩套岩浆事件(1595~1575 Ma)时间一致。通过锆石Ti温度计计算出花岗岩成岩温度为848~971℃,平均878℃,接近A型花岗岩的成岩温度。锆石的稀土元素配分模式呈现轻稀土元素亏损、重稀土元素富集及向左倾斜的特征,具有明显的正Ce异常和负Eu异常,δCe值变化范围较大(4.85~107.63),δEu值变化范围较小(0.17~0.36)。在锆石Y-Yb/Dy等判别图解中,样品多落入板内构造环境范围及附近,少数落入火山弧构造环境范围及附近;在锆石Hf-U/Yb等判别图解中,样品均落入陆壳环境范围。综合分析认为,该花岗岩形成于活动大陆边缘向陆内环境演变的构造背景。The Hiltaba Suite is widely developed in the Gawler Craton,South Australia,which is closely related to the IOCG deposits in the area.It is very important to find out the diagenetic age,diagenetic temperature and tectonic setting of the suite for the study of IOCG deposits.Zircon U-Pb dating of the augen granite collected from the north of the Moonta-Wallaroo mining district in the York Peninsula shows that the age is 1589 ± 43 Ma,which is consistent with the magmatic event(1595~1575 Ma) of the Hiltaba Suite determined by previous geologists.According to zircon Ti thermometer,the diagenetic temperature of granite is 848 ~ 971℃,with an average of 878℃,which is close to that of A-type granite.The rare earth element patterns of zircon show the characteristics of LREE loss,HREE enrichment and left-dip,with obvious positive Ce anomaly and negative Eu anomaly,δCe varies widely(4.85 ~ 107.63) and δEu varies small(0.17 ~ 0.36).In the zircon Y-Yb/Dy and other discriminant diagrams,most of the samples fall within and near the within plate tectonic environment,and a few fall within and near the volcanic arc tectonic environment.In the zircon Hf-U/Yb and Y-Yb/Dy discriminant diagrams,the samples fall within the continental crust environment.Comprehensive analysis shows that the granite was formed in the tectonic setting of the evolution from the active continental margin to the intracontinental environment.

关 键 词：高勒克拉通 铁氧化物铜金矿床 Hiltaba岩套 成岩时代 成岩温度 构造背景 

分 类 号：P595[天文地球—地球化学] P597.3[天文地球—地质学]