新疆托克逊新干沟奥陶纪蛇绿岩  

ORDOVICIAN OPHIOLITE IN XIN’GANGOU OF TUOKEXUN, XINJIANG

作　　者：刘正荣[1] 裴江平[1] 邓东松[1] 孙江华[1] 陶玲[1] 

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局物化探大队,新疆昌吉831100

出　　处：《新疆地质》2005年第4期326-333,共8页Xinjiang Geology

摘　　要：2003-2004年在新疆托克逊干沟地区1:5万区调中,查明博罗科努带北侧新干沟一带为奥陶纪蛇绿岩建造.建造组成成分有:由纯橄岩、斜方辉橄岩等组成的变质橄榄岩;含长橄榄岩、斜方辉石岩、堆晶辉长岩以及上部辉长岩组成的堆积岩;辉绿岩;由玄武岩及其凝灰岩、凝灰质碎屑岩、少量碳酸盐岩、硅质岩等组成的沉积层.建造总厚1 627.5～2 564.5 m,其中镁铁-超镁铁岩体共26个,岩体最大宽度1 000 m,总面积5.2 km2.橄榄岩类M/F 10.16～11.85,辉石岩、堆晶辉长岩M/F 6.64、7.44,与新疆准噶尔地区古生代蛇绿岩中的变质橄榄岩一致.新疆黄山类型含铜镍超镁铁岩不同微量元素及稀土元素特征表明:它们与典型大洋中脊蛇绿岩不同,与新疆多数蛇绿岩相似.应为小洋盆扩张产物.Ordovician ophiolite formation in the Xin＇gangou region on the northern side of Boluokenu belt was mapped during the 1 ： 50,000 regional geological surveying in the Gangou region of Tu0kexun, Xinjiang in 2003- 2004.This formation consisted of metamorphic peridotite derived from dunite and orthopyrolite, feldspar-beating peridotite, orthopyroxenite, cumulus crystal gabbro, accumulative rock with upper gabbro, diabase, and sedimentary beddings made of basalt and related tuff, tuffaceous clastic rock, rare carbonate rock and silicate. The formation has a total thickness of 1627.5～2564.5m and a total area of 5.2km^2. Furthermore, it contains 26 mafic-ultramafic intrusions, with widths up to 1000m. M/F ratios of peridotoid are 10.16～ 11.85, while that of pyroxenite and cumulus crystal gabbro are 6.64 and 7.44 respectively. These characteristics are in line with metamorphic peridotite from Paleozoic ophiolite in Junggar, Xinjiang; however, the characteristics of trace elements and REE were quite different from copper-nickel-bearing ultramafic rocks in Huangshan, Xinjiang. It indicates the ophiolite formation is different from the typical mid-oceanic ridge ophiolite, and is similar to the main ophiolites in Xinjiang. It is supposed to be the product of small ocean basin formation.

关 键 词：新疆 干沟 蛇绿岩 变质橄榄岩 堆晶岩 

分 类 号：P588.1[天文地球—岩石学]