新疆西天山大型铁矿床石炭纪控矿火山机构及成矿模式  

Carboniferous ore-controlling volcanic apparatus and metallogenic models for the large-scale iron deposits in the Western Tianshan,Xinjiang

作　　者：申萍[1,2] 潘鸿迪 李昌昊[1] 冯浩轩[1] 武阳 石福品 郭新成[5] 李文广[1] SHEN Ping;PAN HongDi;LI ChangHao;FENG HaoXuan;WU Yang;SHI FuPin;GUO Xin Cheng;LI WenGuang(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,Uninersity of Chinese Academy of Sciences,Bejing 100049,China;Collge of Earth Sciences,Chang an University,Xian 710054,China;The Third Geological Branch,Xinjiang Geological and Mineral Bureau,Kuerle 841000,China 5.The Eleven Geological Branch,Xinjiang Geological and Mineral Bureau,Changji 831100,China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院矿产资源研究重点实验室,北京100029 [2]中国科学院大学地球与行星科学学院,北京100049 [3]长安大学地球科学与资源学院,西安710054 [4]新疆地质矿产勘查开发局第三地质大队,库尔勒841000 [5]新疆地质矿产勘查开发局第十一地质大队,昌吉831100

出　　处：《岩石学报》2020年第9期2845-2868,共24页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2018YFC0604004、2017 YFC0601206);中国科学院国际合作局国际伙伴计划(132A11KYSB20190070);国家自然科学基金项目(91962213)联合资助。

摘　　要：新疆西天山阿吾拉勒成矿带发育一系列大型海相火山岩型铁矿床,是我国十大重要金属矿产资源接替基地之一,备受关注。该成矿带石炭纪火山活动强烈,前人已经识别出该成矿带东段的区域艾肯达坂破火山口,且查岗诺尔、智博、敦德、备战等大型铁矿床均赋存于下石炭统大哈拉军山组火山岩中,其形成受火山机构控制。然而,迄今为止,这些矿床尚未确.立具体的火山机构,矿床与矿区发育的火山机构关系有待查明;此外,与查岗诺尔、智博、备战等矿床包含单一的铁元素不同,敦德矿床具有Fe-Zn-Au元素组合,其原因尚不清楚。在前人研究基础上,通过野外地质剖面观察和测量,结合室内研究和遥感解译工作,我们认为阿吾拉勒成矿带东段的4个大型铁矿床均独自发育石炭纪与成矿有关的火山机构,且不同矿床,其火山机构的特点及其演化各不相同。其中,查岗诺尔矿区发育圆形破火山口,面积约为10km2,矿床位于破火山口北缘,矿体赋存于破火山口环状断裂系中;智博矿区发育椭圆形破火山口,面积约为15km2,矿床位于破火山口西南部,矿体赋存于经多次塌陷的破火山口环状断裂系中;敦德矿区发育椭圆形破火山口,面积约为6km2,矿床位于破火山口的中部,矿体赋存于火山通道及其附近的环状和放射状断裂系中;备战矿区发育椭圆形火山口,面积约为4km2,矿床位于火山口北缘,矿体赋存于环状断裂系中。可见,只有敦德矿床的矿体赋存于火山通道断裂系中,其余矿床的矿体均赋存于火山机构环状断裂系中;高渗透性的火山机构断裂系为成矿流体迁移和金属沉淀提供了有利的空间,是铁矿体形成的关键控矿因素和赋矿部位。此外,这些铁矿床的成矿年龄(319~304Ma)滞后于容矿火山岩的年龄(328~319Ma),矿体与围岩界线多为渐变关系;成矿作用以热液作用为主,其中,敦德矿区发育单一的热液Numerous large-scale submarine volcanic iron deposits occurred in the Awulale metallogenic belt in the Western Tianshan,Xinjiang,which is one of the ten most important alternative reserves in China,and it has attracted much attention. The Awulale belt is characterized by intensively Carboniferous submarine magmatic activities. Previous studies have recognized a huge Aikendaban oval caldera which occurs in the eastern Awulale belt,and several large-scale iron deposits,including Chagangnoer,Zhibo,Dunde and Beizhan,are found hosting in the volcanic rocks of the Lower Carboniferous Dahalajunshan Formation,which are controlled by this volcanic apparatus. However,so far,the volcanic apparatus within each iron deposit has not been recognized,the relationship between the deposit and the volcanic apparatus is not identified. In addition,unlike the Chagangnoer,Zhibo and Beizhan deposits which contain single Fe metal,the Dunde deposit is characterized by a Fe-Zn-Au assemblage,and its genetic reason is still unclear. On the basis of previous studies,through field geological profile observation and survey,combined with indoor research and remote sensing interpretation,we believe that some Carboniferous volcanic eruption cycles occurred in each iron deposit,forming itself volcanic apparatus which is closely related to iron mineralization. These volcanic apparatus have different characteristics and evolutionary processes for each other. A circular caldera,with an area of about 10 km^2,occurs at Chagangnuoer,and it experienced the collapse of the cratering. The Chagangnuoer deposit is located in the north of this caldera,and the ore body occurs in the ring fault system of the caldera. An oval caldera,with an area of about 15 km^2,occurs at Zhibo,and it also experienced collapsing;the Zhibo deposit is located in the southwest of the caldera,and the ore body occurs in the ring fault system. An oval caldera,with an area of about 6 km^2,occurred at Dunde;the Dunde deposit is located in the central part of the caldera,and the ore bod

关 键 词：海相火山岩型铁矿床 火山喷发旋回 火山机构 成矿模式 新疆阿吾拉勒成矿带 

分 类 号：P317[天文地球—固体地球物理学] P611[天文地球—地球物理学]