东秦岭上房沟超大型钼铁矿床Mo–Fe同位素示踪及其成因分析

The Shangfanggou superlarge Mo–Fe deposit located in Eastern Qinling, Central China, which is a typical porphyry-skarn mineral system developed in the Yangtze-North China regime. The deposit was hosted in a lithologic association comprising carbonaceous sandstone, shale, carbonate and chert within the Neoproterozoic Luanchuan Group. The characteristics and genesis of the molybdenum mineralization of Shangfanggou deposit has been investigated thoroughly by now, while the investigation of iron mineralization is weak. The geological characteristics of the Shangfanggou deposit clearly showed that the molybdenum and iron mineralization started simultaneously, since the proved reserves and the time of duration of molybdenum mineralization is larger and longer than the iron mineralization. The molybdenum-iron mineralization mechanism behind this geological phenomenon haven’t been thoroughly get clear yet. The inadequacy of the research restricted the roundly and objectively understanding of Shangfanggou metallogenic system. The stable isotopes of transition metals (molybdenum, iron, copper, zinc, chromium, etc.) have recently attracted much attention as possible tools for monitoring geochemical processes. Therefore, this project intends to analyze this scientific problem through combining the macroscopic analysis with the micro examination. The broad aspect is to further study and analysis the geological and geochemical characteristics on molybdenum and iron mineralization in Shangfanggou deposit. As to the micro aspect, is to via multi-collector inductively coupled plasma mass spectrometer spectrometry (MC–ICP–MS), choose Mo and Fe, the main ore-forming elements of Shangfanggou deposit, directly investigate source and transportation of metallogenic materials. On the basis of the study, analysis the mechanism and ore genetic relevance about Mo and Fe mineralization of Shangfanggou deposit. The expected achievements of this project will not only provide a comprehensive understanding for the features of high temperature hydrothermal deposits of East Qinling or others formed under continental collision regime, but also, is expected to bring about the breakthrough progress of applied research of non-traditional isotope geochemical methods on the ore deposit research, which would open up new research ideas and methods.

上房沟超大型斑岩-矽卡岩钼铁矿床为东秦岭燕山期钼巨量成矿作用的典型矿床之一。前人多仅针对其钼矿化特征及成因机制，或者将钼–铁矿化不加以区分进行研究，而该矿床地质特征表现出钼、铁矿化发生时间基本一致、但钼矿化强度与持续时长均大于铁矿化，其内在机制至今未有合理解释，导致难以全面客观认识其成矿过程。近年来钼、铁等非传统同位素地球化学发展迅速，为直接示踪金属成矿作用提供了可能。据此，本项目拟从宏观上进一步分析上房沟矿床钼、铁的矿化特征及赋存状态，并重点借助多接收器电感耦合等离子体质谱等测试手段，从微观角度对该矿床各主要地质体开展Mo、Fe稳定同位素分析，示踪其钼、铁成矿物质的来源及演化，探讨两者在矿化过程中的有机关联，深入剖析钼-铁形成机制。该研究成果可为研究栾川矿田及东秦岭钼矿带的成矿过程提供重要参考，并为斑岩–矽卡岩型矿床成矿理论以及钼–铁稳定同位素示踪成矿物质来源研究提供很好的实例。

上房沟超大型斑岩-矽卡岩钼铁矿床为东秦岭燕山期钼巨量成矿作用的典型矿床之一。前人多仅针对其钼矿化特征及成因机制，或者将钼–铁矿化不加以区分进行研究，而该矿床地质特征表现出钼、铁矿化发生时间基本一致、但钼矿化强度与持续时长均大于铁矿化，其内在机制至今未有合理解释，对其成矿过程缺少全面客观认识。本项目通过野外区域观察研究上房沟矿床钼、铁的矿化特征及赋存状态的基础上，结合微观角度对该矿床各主要地质体开展岩矿学和Mo、Fe等同位素分析，示踪其钼、铁成矿物质的来源及演化，探讨两者在矿化过程中的成因关联，深入剖析钼-铁形成机制。该研究成果可为研究栾川矿田及东秦岭钼矿带的成矿过程提供重要参考，并为斑岩–矽卡岩型矿床成矿理论以及钼–铁稳定同位素示踪成矿物质来源研究提供很好的实例。