北疆及邻区石炭-二叠纪花岗岩时空分布特征及其构造意义  

Spatial and temporal distribution of the Carboniferous-Permian granitoids in northern Xinjiang and its adjacent areas,and its tectonic significance

作　　者：童英[1] 王涛[1] 洪大卫[1] 韩宝福[2] 张建军[1] 史兴俊[1] 王超[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]北京大学地球与空间科学学院,北京100871

出　　处：《岩石矿物学杂志》2010年第6期619-641,共23页Acta Petrologica et Mineralogica

基　　金：973项目(2007CB411307);国家自然科学基金资助项目(40702010);基本科研业务费(J0906);中国地质调查局地质调查项目(12123206043;1212010611817)

摘　　要：北疆及邻区发育大量的花岗岩,其中石炭-二叠纪花岗岩较为突出。本文总结了该期花岗岩的时空分布特征。北疆及邻区不同构造单元石炭-二叠纪花岗岩特征不同,形成时代峰期也不一致。在阿尔泰,该期花岗岩主要集中在早二叠世(289～266Ma),晚石炭世出现一个明显的岩浆宁静期;西准噶尔可以分为早石炭世(340～320Ma)和晚石炭世—早二叠世(310～290Ma)两期,后一期较强,铝质A型花岗岩分布广泛是该地区的一个重要特征,形成时代集中在300Ma左右;东准噶尔地区石炭-二叠纪花岗岩多沿断裂带展布,岩浆活动从晚石炭世一直延续到早二叠世(320～270Ma),该地区最大的特点是发育多条碱性(A型)花岗岩带,在晚石炭世—早二叠世连续产出。西天山大致可以分为3期:早石炭世(355～345Ma)、早石炭世晚期—晚石炭世(335～305Ma)和二叠纪(300～255Ma)。早石炭世花岗岩主要集中在北天山,早二叠世花岗岩浆活动最为强烈,其中的碱性(A型)花岗岩不仅在南天山呈带状大面积分布,在北天山也有发育;东天山—北山是区内石炭-二叠纪花岗岩最为发育的地区,岩体数量多,分布面积广,锆石年龄主要集中在335～310Ma和300～270Ma,相对来说来东天山石炭纪花岗岩较多,北山二叠纪花岗岩较多。总体而言,北疆及邻区石炭-二叠纪花岗岩时代主要集中在晚石炭世—早二叠世,特别是早二叠世,整体展现出同步性,这个时期碱性岩最发育,可能揭示了不同构造背景下的伸展特点。这是整个中亚造山带及邻区大量的酸性和基性-超基性岩浆活动及暗示的伸展环境的一个缩影。Numerous granitoids occur in northern Xinjiang and its adjacent areas,with Carboniferous-Permian granitoids being most typical.This paper summarizes the spatial and temporal distribution characteristics of these granitoids.Carboniferous-Permian granitoids show different features in different units,and the peak values of their formation epochs are also different.Formation epochs of the Carboniferous-Permian granitoids in Altay are mainly concentrated in early Permian （289～266 Ma）,and late Carboniferous seemed to be a distinct magmatic calm period.Western Junggar Carboniferous-Permian granitoids formation periods can be subdivided into early Carboniferous （340～320 Ma） and late Carboniferous-early Permian （310～290 Ma）,with the latter being more stronger.Aluminum A-type granites,concentratedly formed at about 300 Ma,are widely spread,constituting an important feature of western Junggar.Carboniferous-Permian granitoids in eastern Junggar occur along the fault zones and were formed mainly from late Carboniferous to early Permian （320～270 Ma）,characterized by the continuous emplacement of quite a number of alkaline （A-type） granites in this region in this period.Carboniferous-Permian granitoids in western Tianshan can be divided into three stages：early Carboniferous （355～345 Ma）,late early Carboniferous-late Carboniferous （335～305 Ma） and early Permian （300～255 Ma）.The early Permian granitic magma activity is the strongest,and Carboniferous granitoids mainly intruded into northern Tianshan,and the early Permian alkaline （A-type） granitoids are not only distributed in a large zonal area of southern Tianshan but also spread in northern Tianshan.Eastern Tianshan-Beishan is an area with most developed Carboniferous-Permian granitoids,characterized by both large quantities and wide distribution.Zircon ages show two obvious peaks,being respectively at 335～310 Ma and 300～270 Ma.Granitoids in eastern Tianshan are mostly Carboniferous ones,whereas granitoids in Beishan are

关 键 词：花岗岩 石炭纪 二叠纪 锆石年龄 伸展 中亚造山带 

分 类 号：P588.121[天文地球—岩石学] P54[天文地球—地质学]