辽南变质核杂岩饮马湾山和赵房岩体锆石SHRIMP U-Pb年龄及其地质意义  

Zircon SHRIMP U-Pb age of Yinmawanshan and Zhaofang pluton in South Liaoning metamorphic core complex and its geological implications.

作　　者：纪沫[1] 刘俊来[1] 胡玲[1] 关会梅[1] G DAVIS 张维[3] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]Department of Earth Sciences,University of South California [3]中国地质科学院地质研究所SHRIMP中心,北京100037

出　　处：《岩石学报》2009年第1期173-181,共9页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(40272084,40472105,90814006)资助.

摘　　要：辽南变质核杂岩形成于晚中生代华北岩石圈伸展和减薄背景下,其演化过程分为三个阶段:第一阶段(约130Ma),在伸展作用下辽南地区发育拆离断层及其下伏韧性剪切带;第二阶段(130～120Ma),同构造花岗质岩体的主动侵位影响了拆离断层的演化;同时在124Ma变质核杂岩的构造-岩浆活动达到峰值;第三阶段(113Ma之后)花岗质岩体在较浅层次侵位于停止活动的拆离断层带。辽南变质核杂岩发育与演化过程在年代学意义上揭示了华北板块晚中生代时期的区域性岩石圈伸展与减薄过程。本文认为由伸展后期侵位的赵房岩体所记录的拆离断层停止的时限(113Ma)可以作为华北岩石圈强烈构造岩浆活动的转捩点,113Ma之前华北板块广泛发育变质核杂岩、拉分盆地等一系列伸展构造,之后则以平稳的隆升和冷却过程为主。South Liaoning metamorphie core complex was formed due to regional extension and lithosphere thinning in North China Craton during Late Mesozoic. The tectono-magmatic evolution of the metamorphic core complexes can be subdivided into three stages. In the first stage (similar to 130Ma), the detachment Fault and ducti e. shear zone. were. formed by the regional extension. During the second stage (130 similar to 120Ma), the. active emplacement of synkinematic granitic plutons influenced the development of detachment fault; at the. same time (124Ma), the tectono-magmatic activity reached the peak value, the third stage (similar to 113Ma), granitic intrusions emplaced at the lower plate of detachment fault which had ceased movement. The tectonic evolution of South Liaoning metamorphic core complex provide evidences for the extension and lithosphere thinning of North China Craton in Late Mesozoic. We considered that the emplacement of post-extensional Zhaofang pluton (113Ma) marks the termination of a series of tectono-magmatic activities during regional extension. After 113Ma, the South Liaoning metamorphic core complex, and the North China Craton experienced a regional uplifting and cooling.

关 键 词：辽南变质核杂岩 花岗质岩石 SHRIMP U-PB测年 早白垩世 

分 类 号：P597.3[天文地球—地球化学]