新疆阿尔泰南缘康布铁堡组的重新厘定

Re-determination of the Kangbutiebao Formation in the Southern Margin of Altay,Xinjiang

区域地质及野外地质剖面研究表明,新疆阿尔泰南缘康布铁堡组的东、中、西3段岩石组合和变质变形及含矿性等方面存在显著差异,有必要对其重新划分厘定。分布于西段克兰及麦兹盆地的康布铁堡组(D1k),通过古生物化石及年代学资料确定其时代为早泥盆世,实测地质剖面显示为一套浅变质酸性火山岩及火山碎屑岩夹正常碎屑岩,自下而上可划分为4个岩性段:笫1岩性段(D1ka)以云母片岩为主;第2岩性段(D1kb)为钙质片岩、钙质砂岩、变凝灰质砂岩;笫3岩性段(D1kc)主要为变酸性流纹岩、凝灰岩;第4岩性段(D1kd)以变流纹岩、流纹质火山碎屑岩为主。而分布于东段青河地区、中段(南部)富蕴地区的康布铁堡组,实为一套混合岩化变质岩系,其时代缺少年代学资料限制,应从康布铁堡组中解体出去,依据进一步变质作用及年代学资料重新划分、命名。

The Kangbutiebao Formation is distributed in the southern margin of Altay,Xinjiang.Based on the regional geology and geological section,this study holds the idea that the Kangbutiebao Formation should be re-determinated on account of the obvious differences in rock assemblages,metamorphic-deformation and ore-bear-ing potential among the eastern,middle and western parts.The age of Kangbutiebao Formation（D1 k）which is located in Kelan and Maizi Basin is of Early Devonian according to the fossils and geochronology.Field measur-ing geological sections reveal that the D1 k include acid volcanic rocks and volcaniclastic rocks interbedded nor-mal clastic rocks （low-grade metamorphic）.It can be divided into four lithologic units from bottom to top：the first lithologic unit （D1ka）is mainly of micaschist;the second （D1kb）contains calcareous schists,calcareous sandstones and meta-tuffaceous sandstones;the third （D1 kc ）chiefly comprises meta-acid rhyolite and tuff;and the fourth （D1kd）is mainly meta-rhyolite and meta-rhyolitic pyroclastic rocks.But the ‘Kangbutiebao Forma-tion’in Qinghe region （the eastern part）and Fuyun region （the southern section of the middle part）consists of high-grade metamorphic and migmatization rocks and is less of geochronology data,and it should be disintegra-ted from the D1 k and be re-determinated and be renamed after the further study of metamorphism and geochro-nology in this area.