辽东半岛侏罗纪花岗岩的年代学、成因及其地球动力学背景

Petrogenesis and geodynamic setting of Jurassic granitoids in the eastern North China Craton is the key to understand the deep geological processes of Yanshan Movement and decratonization of the North China Craton. However, it is still controversial about their origin and geodynamics. Jurassic granitic intrusions with complex rock types are intend to be studied in this project, which are widely distributed in the Liaodong Peninsula. On the basis of detailed field observations, petrological and mineralogical studies, high-precision zircon and titanite U-Pb age determinations will be presented, with the aim of constraining the spatial and temporal distributions of the Jurassic granites in the Liaodong Peninsula. Combined with whole rock major element, trace element and isotopic analysis, in-situ trace element and isotopic analysis of minerals (including zircon Hf-O isotopic analysis, apatite Sr-Nd isotopic analysis, titanite Nd isotopic analysis and garnet zonation trace element analysis) will be conducted, in order to reveal the origin, petrogenesis and geodynamics of the Jurassic granites in the Liaodong Peninsula, and provide predominant evidence for the decratonization of the North China Craton.

华北克拉通东部侏罗纪花岗岩的成因及地球动力学背景是探索燕山运动深部过程和华北克拉通破坏的窗口，然而在花岗岩的成因和动力学机制上却存在很大争议。本项目拟以辽东半岛大面积分布的、岩性复杂的侏罗纪花岗岩为例，在详细野外观察、岩石学及矿物学研究基础上，通过高精度锆石及榍石U-Pb 年代学研究，准确厘定辽东半岛侏罗纪花岗岩的时空分布格架。通过单矿物原位微区同位素及微量元素测定新技术（锆石Hf-O 同位素，磷灰石Sr-Nd 同位素，榍石Nd 同位素以及石榴石成分环带分析），结合全岩主量元素、微量元素及同位素分析，查明辽东半岛侏罗纪花岗岩的岩浆源区、成岩过程及地球动力学背景，为华北克拉通破坏的相关研究提供新的资料和证据。

华北克拉通东部侏罗纪花岗岩的成因及地球动力学背景是探索燕山运动深部过程和华北克拉通破坏的窗口。辽东半岛发育大面积、岩性复杂的侏罗纪花岗岩，然而在花岗岩的成因和动力学机制上却存在很大争议。在详细野外观察、岩石学及矿物学研究基础上，通过高精度锆石U-Pb 年代学研究，获得辽东半岛北部侏罗纪花岗岩形成于166~173 Ma，与半岛南部该期岩浆活动时代一致。四个典型岩体的锆石Hf同位素具有较大的变化范围，结合全岩主量元素、微量元素分析，表明研究区内侏罗纪花岗岩具有复杂的岩浆源区，包括古老下地壳，新生下地壳及幔源物质。辽东半岛北部侏罗纪花岗岩由下地壳物质的部分熔融产生的岩浆，经历了幔源物质加入，围岩混染及结晶分异作用最终形成。