矿床地质2011，Vol.30Issue(6)：979-1001,23.
洛南-卢氏地区与铁铜多金属矿床有关的中酸性侵入岩锆石U-Pb定年及其地质意义
LA-ICP-MS zircon U-Pb dating of granitoid intrusions related to ironcopper polymetallic deposits in Luonan-Lushi area of southern North China Craton and its geological implications
摘要
Abstract
Granitoid intrusions, which Eire widely distributed in Luonan-Lushi area on the southern margin of the North China Craton, consist mostly of K-feldspar granite porphyry and quartz diorite and are closely related to lots of porphyry and skarn Fe-Cu-Mo-Pb-Zn polymetallic deposits in this area. Nevertheless, precise numerical constraints on the emplacement ages of these intrusions, which are of importance in the understanding of the tectonic setting of regional magmatism, are very insufficient. In this paper, the authors present high-precision zircon U-Pb ages of seven representative granitoid intrusions by using laser ablation inductively coupled plasma massspectrometry. The results indicate that these intrusions were emplaced in the time interval from (158 + 2) Ma to (131 ±1) Ma (2a), suggesting that they are products of Late Jurassic to Early Cretaceous magmatism. The age data also show that the quartz diorites were emplaced in a short-lived magmatic pulse at the end of late Jurassic [ (150 + 1) Ma~ (149 ± 1) Ma] , whereas the K-feldspar granite porphyries were emplaced in a prolonged period between (158 + 2) Ma and (131 + 1) Ma. Zircon U-Pb ages of the granitoid intrusions also pose important constraints, for the first time, on the timing of related porphyry and skarn polymetallic deposits in Luonan-Lushi area. These results, in combination with data available, document an extensive magmatic event at the southern edge of the North China Craton that commenced in the late Jurassic, climaxed in the Early Cretaceous and continued until the end of Late Cretaceous. This magmatic event occurred in an extensional environment related to the lithospheric thinning of North China Craton. Age and distribution of the late Mesozoic intrusions in southern North China Craton have shed light on the timing and extent of the Mesozoic decratonization of North China Craton.关键词
地质学/锆石U-Pb定年/LA-ICP-MS/洛南-卢氏/华北南缘/克拉通破坏Key words
geology, zircon U-Pb dating, LA-ICP-MS, Luonan-Lushi area, North China Craton, decratonization分类
天文与地球科学引用本文复制引用
胡浩,李建威,邓晓东..洛南-卢氏地区与铁铜多金属矿床有关的中酸性侵入岩锆石U-Pb定年及其地质意义[J].矿床地质,2011,30(6):979-1001,23.基金项目
本文得到国家自然科学基金重大研究计划重点项目(No.90814004)、中央高校基本科研业务费专项资金(CUG090102)、地质过程与矿产资源国家重点实验室科技部专项经费(MSFGPMR201005)的联合资助 （No.90814004）
