Geological and geochemical characteristics and formation mechanisms of the Zhaishang Carlin-like type gold deposit, western Qinling Mountains, China
Geological and geochemical characteristics and formation mechanisms of the Zhaishang Carlin-like type gold deposit, western Qinling Mountains, China
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DOI：
10.1016/j.oregeorev.2014.07.016
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发表时间：
2015
影响因子：
3.3
通讯作者：
Jiajun Liu;Hongzhang Dai;D. Zhai;Jianping Wang;Yin‐Hong Wang;Longbo Yang;Guangjian Mao;Xinhui Liu-Xin
中科院分区：
文献类型：
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作者：
Jiajun Liu;Hongzhang Dai;D. Zhai;Jianping Wang;Yin‐Hong Wang;Longbo Yang;Guangjian Mao;Xinhui Liu-Xin
寨上金存款矿床位于西秦岭民立成矿带西段，是近年来发现的一个大型卡林型浸染型金存款矿床。矿床存款产于浅变质的中泥盆统和下二叠统碎屑岩建造中，由石英砂岩、粉砂岩、钙质板岩和泥质灰岩组成。金矿化严格受断裂带控制。矿石中的矿物相当复杂，由硫化物、硫盐、氧化物、硫酸盐、碳酸盐、钨酸盐、碲化物、自然金属和多金属合金组成。矿石中矿物的多样性和显微可见自然金的存在构成了该金存款的突出特点，所有样品均表现出稀土配分模式，认为该存款的矿源与赋矿岩石有密切关系。S、C、Pb、H、O同位素组成表明，成矿元素主要来源于围岩、下伏岩石，部分来源于深部。研究表明，成矿流体主要来自活跃的大气降水系统。矿化和相关蚀变具有低水岩比的特征。成矿温度估计在120至240 °C之间。含铁灰岩在容矿岩石中的溶解作用和成矿流体引入的H2S对溶解铁的硫化作用不仅是寨上金存款中显微可见金颗粒存在的最重要的沉积机制，也是金富集的有利条件。
Located in the western part of the Min–Li metallogenic belt within the western Qinling Mountains, the Zhaishang gold deposit is a giant Carlin-like disseminated gold deposit discovered recently. The ore deposit is present both in rocks of low grade metamorphic Middle Devonian and Lower Permian clastic formation, which is composed of quartz sandstone, siltstone, calcareous slate and argillaceous limestone. Gold mineralization is strictly controlled by a fault zone. Minerals in ores are quite complex and consist of sulfides, sulfosalt, oxides, sulfate, carbonate, tungstate, telluride, native metals, and polymetallic alloys. The diversity of mineral in the ores and the existence of microscopic visible native gold constitute the outstanding features of the gold deposit.We believe that the mineral source of the ore deposit has a close connection with the host rocks, because all samples show the light of the REE distribution patterns. The S, C, Pb, H and O isotopic compositions show that the ore-forming elements were mainly derived from the country rocks, the underlying rocks, and partially deep sources. Data obtained suggest that the ore-forming fluids were derived predominantly from an active meteoric groundwater system. Mineralization and related alteration have features of a low water/rock ratio. Ore-forming temperatures are estimated to have been in the range from 120 to 240 °C. The dissolution of ferruginous limestone in the host rocks and the sulfidation of the dissolved iron by H2S introduced by ore fluids constituted not only the most important depositional mechanisms for the existence of microscopic visible gold grains but also favorable conditions for gold enrichment in the Zhaishang gold deposit.