【作者】 赵战锋；

【导师】 薛春纪；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2009， 博士

【摘要】 准噶尔东北缘哈腊苏-哈旦孙斑岩铜矿带可能是中亚-蒙古成矿域中包括欧玉陶勒盖、查干苏布尔等重要斑岩铜矿在内的南蒙古成矿带的西延部分,成矿潜力较大。近年来矿带内相继有希勒克特哈腊苏和玉勒肯哈腊苏斑岩铜矿和众多矿点发现。本文是在矿带内地质测量、矿点检查等野外工作的基础上,结合室内岩相学、矿相学、流体包裹体和同位素地球化学研究,取得如下认识。(一)新发现的玉勒肯哈腊苏矿床中矿石具有浸染状矿化,金属矿物组合简单,主要是黄铜矿、黄铁矿、辉钼矿和磁铁矿,蚀变分带清晰,从矿体中心向外依次是钾长石化带、黑云母化带、绢英岩化带和青磐岩化带,斑岩型矿化的特征比较明显。(二)玉勒肯哈腊苏矿床两个含矿岩体(斑状花岗岩和石英二长斑岩)的锆石U-Pb年龄分别为381.6±2.5Ma和265.6±3.7Ma,锆石特征显示其均为岩浆成因,结合矿床地质研究,认为在玉勒肯哈腊苏地区可能存在早中泥盆世和早二叠世两期斑岩矿化。(三)玉勒肯哈腊苏石英二长斑岩体中石英的δD值为-98.8～-84.2‰,δ18OH2O=0.4～4.7‰,显示成矿流体主要来源于岩浆水。流体包裹体的体积小,数量多,盐度(1.27～17.96wt%)变化范围较大,结合矿石中含有较多磁铁矿,认为成矿流体具有富水、富氯、氧化等特征。黄铁矿中的δ34SV-CDT=-3.795～-1.766‰,全岩εNd(t)和(87Sr/86Sr)i分别是12～12.5,0.70343～0.70423,证明成岩成矿物质主要来源于地幔。(四)玉勒肯斑状花岗岩La/Nb(均值1.02),Nb/U(13.09),和Hf-Ta-Rb判别图显示该区中泥盆世为岛弧背景,而厚层苦橄岩出露暗示可能存在微裂谷,致使幔源物质得以上涌。石英二长斑岩微量元素特征及同期区内外的基性岩体表明其形成于早二叠世新陆壳阶段的张弛期,局部石英脉中的富矿体可能是印支期构造-岩浆活动的产物。(五)哈腊苏矿田中泥盆世、早二叠世、三叠纪多阶段成矿作用的复合类似于中亚-蒙古成矿域中晚古生代成矿,主要是对已有成矿物质的继承、改造和新成矿物质的叠加。其和南蒙古成矿带都处于西伯利亚弧形深大断裂南缘岩浆岛弧带内,位置上均在晚古生代隆起和中新生带凹陷的分界,地层建造、岩浆发育也有类似,因此认为哈腊苏矿田可能是南蒙古成矿带的西延部分。(六)在地层、构造和勘查地球化学成果研究的基础上,认为北部围岩封闭条件好,更利于斑岩铜矿的形成,且剥蚀深度小也利于斑岩铜矿的保存,从而确定希-玉接壤地带是斑岩铜矿勘查的有利区域。结合对南北向断裂性质的分析,确定奥尔塔哈腊苏西是另外一个斑岩铜矿勘查的有利区域。地、物、化综合研究显示构造蚀变岩型矿床的勘查有利区在矿带中部,而岩浆型矿床更有可能在南部形成。更多还原

【Abstract】 The porphyry copper belt of Halasu-Hadansun,northeast margin of Junggar is perhaps part of western extension part of the Mongolia metallogenic belt which belongsto central Asia-Mongolia mineralization domain,including many important porphyry copper deposits,such as ouyutolgoi and chagan subul deposits. Therefore,there wasenormous metallogenic potential in that area. In recent years, Xileketehalasu andYulekenhasula porphyry copper deposits and many other porphyry copper mineraloccurrences were discovered consecutively in this belt. Based on the field works such asgeological survey and ore occurrences check in metallogenic belt, together with study ofpetrography, mineralography, fluid inclusion and isotope geochemistry, this papergeneralizes a few conclusions as follows:The newly-discovered Yunlekenhalasu deposit in the porphyry copper belt ofHalasu-Hadansun in the northeast margin of Junggar has distinct Characteristics of porphyry mineralization, such as disseminated mineralization, simple metallic mineralassociation, mainly Chalcopyrite, pyrite, molybdenite and magnetite, and clear alterationzonation: from the central to the external are belts of potash feldspathization,biotitization, sericite-quartz alteration, propylite alteration in succession.Zircon U-Pb dating of the two ore -bearing rock body, porphyritic granite and Beschtauite porphyry in Yuleken-Halasu deposit are 265.6±3.7Ma and 381.6±2.5Ma,respectively. The characteristics of the zircon which show its genesis was magmatic,together with the former research on chronology in Xilekehalasu, show that there weretwo periods for porphyry mineralization which are Early-Middle Devonian and Early Permian.Research on H-O isotope and fluid inclusion in Yuleken-Halasu deposit proves that metallogenetic fluid mainly derived from magmatic water and mixed with atmosphericwater latterly. The metallogenetic fluids with a small volume and a large quantity, have alarge range of halite (1.27~17.96wt%). Together with the ore relatively rich in magnetite,the metallogenetic fluids have some characteristics as follows: rich in water, andchlorine, as well as oxidation.δ34SV-CDT of the pyrite in Yuleken-Halasu deposit is -3.795‰~-1.766‰, andεNd(t)and (87Sr/86Sr)I of the whole rock are 12~12.5 and0.70343~0.70423,respectively, which proves that the source of the mineralizationderives from mantle. Porphyritic granite in the mining area shows that it was Island-arc background in Middle Devonian and the outcrop of thick-layered picrite implies that there exists micro rift which made the mantle-derived material uplift. The trace element characteristics ofthe beschtauite porphyry, as well as the basic rock of the internal and external area in the same stage show that the rock in this area forms at Early Permian when the newcontinental crust was in the condition of extension. High-grade ore body of the local quartz veins may be the result of tectonic - magmatic activity in the Indo-Chinese epoch.The characteristics of the superposition of the multistage metallogenesis in MiddleDevonian, Early Permian and Triassic is similar to that of the typical mineralization inthe Central Asia - Mongolia metallogenic domain, which is mainly inheritance and transformation of the previous ore-forming materials and superposition of the newlyore-forming materials. Both this and Southern Mongolia metallogenic belt ,in themagmatic island-arc belt ,are located in the southern margin of arc-shaped deep and large fault and both are in the dividing line of the Late Paleozoic uplift and Mid-Cenozoic depression. Therefore this mining area belongs to the part of Western extension part ofthe South Mongolia metallogenic belt.Based on the study of the strata, structure and geochemical exploration, the closed condition of the country rock in the northern part is better than the others making itpreferential to form porphyry copper deposit, and the little erosion helped preserve themine which made the Contiguous zone of Xi-Yu become a preferential area for the exploration of the porphyry copper deposits. Together with the analysis of nature of theN-S strike fault, the west of Aoertahalsu is another area for the exploration of theporphyry copper deposits. Synthetic study of the geological, geophysical, and geochemical data, shows that the preferential area of the exploration of structural alteredrock type deposits is located in the central part of the mineralizing belt and magmatictype deposits have a large possibility to form in the south.更多还原