摘要
对宁镇地区安基山岩体主要岩石类型花岗闪长斑岩的SHRIMP锆石U-Pb定年结果表明,安基山岩体的花岗闪长斑岩SHRIMP锆石U-Pb年龄为(106.9±0.9)Ma,代表了岩体形成年龄,岩体形成于早白垩世晚期;安基山岩体的形成明显晚于铜陵等地高钾钙碱性中酸性侵入岩形成时代,揭示出宁镇地区中酸性钙碱性岩浆活动及其成矿响应是中生代长江中下游成矿带大规模岩浆活动的另一期成岩成矿事件;宁镇地区铜多金属成矿作用在时间、空间和成因上与107Ma左右的钙碱性中酸性岩浆活动有密切的联系,区内成岩成矿作用是一个连续的过程;宁镇地区钙碱性中酸性岩浆活动的地球动力学背景对应中国东部中生代岩石圈拆沉减薄事件;长江中下游地区岩石圈拆沉从130Ma左右开始,可能一直持续到107Ma以后.
The SHRIMP zircon U-Pb dating of granodiorite^porphyry, the main rock type of Anjishan rock mass yields the age of 106.9＋0. 9 Ma, as the formation age of the Anjishan rock mass, which shows that the Anjishan rock mass formed in the late Early Cretaceous. Anjishan rock mass is younger than the high-K calc-alkaline intermediate-acidic intrusive rocks in Tongling and other districts and it illustrates that the intermediate-acidic intrusive rocks in Ningzhen District belongs to another diagenetic event in the middle to lower Yangtze metallogenic belt＇s Mesozoic large magmatism The Ningzhen District＇s Cu-poly- metallic mineralization is closely related with the 107 Ma calc-alkaline intermediate-acidic magmatism in time, space and origin. The petrogenesismineralization has been a continuous process in this district. The geodynamics background of the Ningzhen District＇s calc-alkaline intermediate-acidic magmatism corresponds to the Mesozoic lithospheric delamination thinning event in Eastern China. It demonstrates that the middle to lower Yangtze lithosphere delamination began at aboutl30 Ma, and lasted to 107 Ma or later.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2013年第1期57-67,共11页
Earth Science-Journal of China University of Geosciences
基金
中国地质调查局资源评价项目(Nos.1212010781014
1212010660404)
中国地质大学地质过程与矿产资源国家重点实验室开放基金(No.MGMR2001-1)
