华北克拉通中北部古元古代碰撞造山时限:来自强过铝花岗岩和韧性剪切时代的制约  

PALAEOPROTEROZOIC COLLISIONAL TIME IN THE SANGGAN AREA OF THE NORTH CHINA CRATON:CONSTRAINTS FROM AGE OF REGIONAL DUCTILE SHEARING AND POST-COLLISIONAL SUPER PERALUMINOUS GRANITES

作　　者：张华锋[1] 罗志波[1] 周志广[1] 柳长峰[1] 

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

出　　处：《矿物岩石》2009年第1期60-67,共8页Mineralogy and Petrology

基　　金：国家自然基金项目(40772122);国土资源部地调局华北地区基础地质调查及数据更新项目(1212010811001)

摘　　要：运用将古元古代强过铝花岗岩和区域韧性剪切作用时代相结合的方法，探讨华北克拉通中北部古元古代碰撞时限，通过定向显微构造观察和角闪石矿物化学研究表明，区域拉伸线理形成于中压麻粒岩相条件；韧性剪切作用方向与拉伸线理走向一致，大量显微观察表明韧性剪切发生在中压麻粒岩相退变过程；根据已有的强过铝花岗岩岩石化学和时代以及区域韧性剪切时代等资料，结合麻粒岩变质PT轨迹和同住素年代学数据，提出高压麻粒岩的峰期时限应在1950Ma～1900Ma，而l900Ma～1800Ma为碰撞后抬升过程中的中压麻粒岩相和角闪岩相退变作用。The timing of Paleoproterozoic collision in the Sanggan area of the North China Craton was discussed on the basis of study of super peraluminous granite and regional ductile shearing. The NEE trend regional stretched lineation and ductile shear zones were formed during granulite retrogression,evidenced by mineral assemblage,amphibole composition and deformation features of the high-pressure granulites. Ductile shearing occurred in super peraluminous granites with formation of typical minerals of garnet, cordierite and sillimanite, indicating that they were resulted from magmas duo to partial melting of khondalites in post-collisional extensional regime and formed earlier than that of the lineation and ductile shear zones. According to the metamorphic P-T paths of the high-pressure granulites and khondalites,timing of ductile shearing and emplacement age of the peraluminous granites, it was proposed that the time of the collision orogen may be earlier than 1900 Ma and the ages of 1 900 Ma-1800 Ma, might represent the time of granulite and amphibole facies retrogression. It was indicated that the chronological data obtained from zircons of the high-pressure granulites may be representative of retrograde time, but not peak time of continental collision.

关 键 词：华北克拉通 桑干地区 古元古代 高压麻粒岩 碰撞造山峰期时限 

分 类 号：P542.2[天文地球—构造地质学]