投稿时间：2024-01-05
修订日期：2024-03-14
网络发布日期：2024-04-25
中文摘要:内蒙古边家大院锡多金属矿床是大兴安岭南段多金属成矿带的代表性矿床之一，其西矿区主要发育斑岩型Sn-Cu-Mo矿体，矿体发育于石英斑岩体内。文章通过对石英斑岩开展全岩地球化学、锆石Hf同位素以及锆石微量元素地球化学分析研究，确定了该含矿岩体岩浆性质、来源及演化历史，探讨了成岩成矿关系，并进一步评估了该岩体成锡、铜矿潜力。研究表明，边家大院石英斑岩为准铝质-弱过铝质，高钾钙碱性花岗岩。稀土元素具有轻稀土元素富集、重稀土元素亏损，Eu负异常明显的特征。微量元素具有富集大离子亲石元素，亏损高场强元素的特征。结合其较低的Zr/Hf和Nb/Ta比值以及较高的Rb/Sr比值判断其经历了高分异结晶演化。根据锆石微量元素地球化学特征，确定边家大院石英斑岩源于还原性（ΔFMQ-0.15）、高温贫水（> 750oC）岩浆。边家大院石英斑岩εHf（t）为-0.86~5.99，TDM2=809~1240 Ma，为中元古代-新元古代年轻地壳部分熔融形成。根据锆石微量元素Ce4+/Ce3+，CeN/CeN*，Ce/Nd和EuN/EuN*指针性比值及岩浆特性判断，该石英斑岩有利于锡金属富集成矿，而成铜钼矿潜力小。
Abstract:The Bianjiadayuan deposit is one of the representative polymetallic deposits in the southern Great Xing'an. The western sector of the deposit is distinguished by its development of porphyry-type Sn-Cu-Mo ore bodies, intricately associated with quartz porphyry. Incorporating whole-rock geochemistry, zircon Hf isotopes, and zircon trace element analysis revealed the magmatic properties, origin, and evolution of the ore-bearing quartz porphyry. This study indicates the quartz porphyry, with εHf(t) values ranging from -0.86 to 5.99 and TDM2 ages between 809 and 1240 Ma, originated from the partial melting of young Neoproterozoic crust. The rock is aluminous to weakly peraluminous, high-potassium calc-alkaline granite, enriched in light rare earth elements and large ion lithophile elements, but depleted in heavy rare earths and high field strength elements. The geochemical signatures, including low Zr/Hf and Nb/Ta ratios and a high Rb/Sr ratio, suggest the magmatic source underwent significant differentiation during its crystallization process. Zircon trace element characteristics point to a reductive (ΔFMQ-0.15), high-temperature (> 750℃), water-poor magmatic source. Based on zircon geochemical indicators and magmatic features, the quartz porphyry is deemed favorable for tin enrichment and mineralization, but less so for copper and molybdenum. This research not only sheds light on the intricate processes governing the mineralization of the Bianjiadayuan deposit but also contributes to the broader understanding of magmatic systems and their mineralization potential in similar geological settings.
keywords:reductive magma water-deficient magma highly fractionated granite southern great Xing'an Bianjiadayuan deposit
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基金项目:本文得到国家自然科学基金（编号：92062218）和国家自然科学基金青年基金项目（编号：41672095）联合资助
引用文本：
张雪旎,王佳新,张阳阳,袁顺达.2024.内蒙古边家大院锡多金属矿床成矿岩体岩石地球化学特征及成矿潜力评价[J].矿床地质,43(2):429~442ZHANG XueNi,WANG JiaXin,ZHANG YangYang,YUAN ShunDa.2024.Comprehensive geochemical profiling and mineralization potential assessment of ore-forming intrusions in Bianjiadayuan tin polymetallic deposit, Inner Mongolia[J].Mineral Deposits43(2):429~442
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