【作者】 徐卫东；

【导师】 翟裕生；

【作者基本信息】 中国地质大学（北京） ， 矿物学、岩石学、矿床学， 2006， 博士

【摘要】 北祁连西段桦树沟铁铜矿是西北地区一个非常重要的矿床,其复杂的形成过程深刻地反映了区域的地质演化历史。本文在作者生产实践获得的地质资料的基础上,对此进行了深入研究,取得如下主要成果:1.对北祁连西段早古生代前构造演化历史提出了新的认识。①认为敦煌岩群既有元古界,也有太古界,获得3488Ma的年龄值;②经对小风沟超基性岩的研究,提出蓟县纪可能有洋盆存在;③新建由海沟浊积岩、蛇绿岩套和放射虫硅质岩组成的奥陶系碱泉子沟俯冲杂岩构造单元;④认为北祁连西段志留纪系为一套完整的Ⅰ型层序,其Ⅰ型层序界面对应残留盆地形成时盆地边界条件的突变,旱峡组地层反映的海退,对应盆地消亡;⑤黑下佬二长花岗岩形成于加里东造山运动同碰撞期,并获得345.5(±37)Ma的年龄值。2.对桦树沟铁铜矿床进行了深入研究。①认为千枚岩、碧玉岩型两类矿石经历了不同程度的后期改造作用影响,在地球化学特征上不具明显的可分性;②主元素的聚类分析表明,铁铜矿床的形成与沉积作用关系密切;③围岩、铁矿石、铜矿石及石英闪长岩稀土元素特征既有独特性又有继承性,反映了不同程度的岩浆热液叠加改造;④矿床部分特征可与典型的SEDEX型矿床对比;⑤F10断裂为同生断层,并在岩浆热液叠加改造阶段复活,在桦树沟铁铜矿床的形成过程中起到了重要作用;⑥矿床的形成是多源多期多成因的。3.将桦树沟铁铜矿床的形成与北祁连西段板块构造演化过程相联系,提出矿床的形成有三个阶段。①朱龙关群沉积期为矿床的形成开始了物质储备;②镜铁山群沉积期,SEDEX型成矿作用形成桦树沟铁铜矿层;③加里东晚期,俯冲板块边界环境的岩浆热液对矿床进行了改造,使其中的铜元素进一步富集,最终形成桦树沟铁铜矿床。4.以成矿系统理论为指导对北祁连西段桦树沟铁铜成矿组合的成矿环境、基本要素、成矿过程及其作用产物进行了总结,建立了矿床成因模式。5.针对区域成矿特征进行了成矿预测,划分出七个Ⅴ级成矿预测区,可作为今后区内地质找矿实践的参考。更多还原

【Abstract】 The Huashugou Fe-Cu deposit in the western sector of the Northern Qilianshanis an important type in Northwest China, its complicated formation process reflectsthe regional geological evolution history. The author made a detail study on this in thedissertation. The main achievements are as follows:1. The plate tectonic evolution of the west sector of the Northern Qilianshan hasbeen restructured. ①The Donghuang Group is composed of both Proterozoic andAchean, an age of 3488Ma is gotten. ②There might exist oceanic crust duringJixianian period based on the study of Xiaofengou ultrabasic rocks. ③ A newtectonic unit, Jianquanzigou Ordovician subduction complex, was founded, whichconsists of trench turbidites, ophiolites and radiolarian silicalites. ④ The Silurian is aset of Ⅰt ype sequence that include a lowerstand systems tract, a transgressivesystems tract and a highstand systems tract. ⑤ The Heixialao adamellite have beenconfirmed as a Caledonian syn-collisional ploton with an age of 345.5(±37)Ma. .2. The author made a thorough studied on the Huashugou Fe-Cu deposit. ①Two type of ores(phyllite-type and jasperite-type) have been reworked to differentdegrees by later reformation so that they can not be distinguished by geochemicalcharacteristics. ② The cluster analysis of the main elements of the deposit showsthat the formation of the Fe-Cu deposit is closely related to sedimentation. ③ TheREE features of the wall rocks, iron ores, copper ores, and quartz diorite are related toone another , showing that they are reformed by magmatic hydrothermal process todifferent extent. ④ Some characteristics of the deposit can be compared to otherSEDEX type deposits. ⑤The F10 is a contemporaneous fault, which reacted duringthe magmatic hydrothermal reformation stage, played an important role in theformation of the Huashugou Fe-Cu deposit. ⑥ The deposit is formed throughmulti-stage, with multi-resource, and by multi-origin.3. The formation of the Huashugou Fe-Cu deposit has been related to the platetectonic evolution of the western sector of the Northern Qilianshan and the formationof the deposit can be divided into three stages: ① during the sedimentation of theZhulongguan Group in a rift, submarine volcanoes have reserved ore substances forthe formation of the deposit;② during the sedimentation of the Jingtieshan Group,sedimentary exhalation formed the primal deposit;③ during late Caledonian, themagmatic hydrothermal in a subduction setting reformed the Huashugou Fe-Cudeposit, making Cu enrich more, and forming the deposit.4. The author has summarized the basic elements, processes, and products of themetallogenic system of the Huashugou Fe-Cu association in the western sector of theNorthern Qilianshan,and constructed a model for the origin of the Huashugou Fe-Cudeposit.5. The author has carried out metallogenic prediction according to the regionalmetallogenic features, marking off six prediction districts, that is of significance forfuture geological prospecting.更多还原