喀什凹陷乌拉根铅锌矿床岩石磁学特征及地质意义  

Rock magnetic and geological significance of the Uragan Pb‑Zn deposit in the Kashgar Depression

作　　者：侯丹凤 亚夏尔·亚力坤 张博文 张宇昕 吴胜辉 王伟[1] 依力哈木江·吐尼亚孜 Hou Danfeng;Yaxiaer·Yalikun;Zhang Bowen;Zhang Yuxin;Wu Shenghui;Wang Wei;Yilihamujiang·Tuniyazi(Laboratory of Continental Dynamics and Metallogenic Prognosis of Central Asian Orogenic Belt,Urumqi 830049;Xinjiang Railway Survey and Design Institute Co.,Urumqi 830011;Ninth Geological Brigade of Xinjiang Uygur Autonomous Region Geological Exploration and Development Bureau,Urumqi 830000)

机构地区：[1]新疆大学,中亚造山带大陆动力学与成矿预测实验室,乌鲁木齐830049 [2]新疆铁道勘察设计院有限公司,乌鲁木齐830011 [3]新疆维吾尔自治区地质勘查开发局第九地质大队,乌鲁木齐830000

出　　处：《地质科学》2023年第3期924-944,共21页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:4210020477)资助。

摘　　要：乌拉根铅锌矿床位于喀什凹陷西北缘,自中生代以来,喀什凹陷经历了多期次构造运动,这使乌拉根铅锌矿床的铅锌层位沉积环境更为复杂,岩石磁学和古地磁学的研究也更加必要。本研究通过等温剩磁获得曲线与退磁曲线、矫顽力谱分析、磁滞回线与Day图、一阶反转曲线(FORC)、Lowrie三轴热退磁曲线等一系列岩石磁学实验,针对乌拉根铅锌矿床下白垩统克孜勒苏群含矿层位进行了岩石磁学特征研究。岩石磁学分析结果得出,乌拉根铅锌矿床下白垩统克孜勒苏群中灰白色砂岩、灰白色砂岩(贫矿)与灰白色砂岩容矿矿石的磁性矿物以磁铁矿为主,并存在少量的赤铁矿及磁赤铁矿,磁铁矿磁畴类型为多畴与假单畴颗粒混合,赤铁矿为单畴。红褐色砂岩、泥岩及红色砾岩磁性矿物以赤铁矿为主且含有少量磁铁矿,磁畴类型以单畴和多畴颗粒混合为主,存在少部分假单畴颗粒。结合前人的研究与本次野外调查及岩石磁学实验结果,综合推测乌拉根铅锌矿床可能受印度板块-欧亚板块碰撞的持续影响,塔里木盆地发生了陆内造山运动,喀什凹陷内大量流体活化并发生迁移,成矿流体在下白垩统克孜勒苏群内与原岩发生热或水-岩化学作用,进而随流体运移的含矿物质沉淀成矿。The Uragan Pb‑Zn deposit is located at the northwest margin of the Kashgar Depression,which has undergone multiple phases of sub‑tectonic movements since the Mesozoic,making the depositional environment of the Pb‑Zn horizon of the Uragan Pb‑Zn deposit more complex and the study of rock magnetism and paleomagnetism more necessary.In this study,a series of rock magnetic experiments including isothermal remanence acquisition and demagnetisation curves,coercivity spectral analysis,hysteresis lines and Day diagrams,first‑order reversal curves(FORC)and Lowrie triaxial thermal demagnetisation curves were carried out to characterise the ore‑bearing horizons of the Lower Cretaceous Kizilsu Group of the Ulagan Pb‑Zn deposit.The magnetic analysis of the results shows that the magnetic minerals of the grey‑white sandstone,grey‑white sandstone poor ore and grey‑white sandstone ore‑bearing ore in the Lower Cretaceous Kizilsu Group of the Uragan Pb‑Zn deposit are dominated by magnetite with small amounts of hematite and magnetohematite,and the magnetic domains of magnetite are mixed with pseudo‑single‑domain particles,while hematite is single‑domain.The reddish brown sandstone,mudstone and red conglomerate are dominated by hematite and contain a small amount of magnetite,with a mixture of single and multiple domains and a few pseudo‑single domains.Combining the results of this rock magnetic experiment with previous studies on the mineralisation mechanism of the Uragan Pb‑Zn deposit,it is inferred that the Uragan Pb‑Zn deposit may have been influenced by the ongoing Indian plate‑Eurasian plate collision,the intra‑land orogenic movement in the Tarim Basin,the activation and migration of a large number of fluids in the Kashgar Depression,the thermal or water‑rock chemistry of the mineralising fluids with the original rocks in the Lower Cretaceous Kizilsu Group,and the subsequent precipitation of mineralised material with the fluid transport.

关 键 词：乌拉根铅锌矿床 岩石磁学 板块碰撞 磁铁矿 成矿机制 

分 类 号：P318.4[天文地球—固体地球物理学] P534.53[天文地球—地球物理学]