Crustal magmatic controls on the formation of porphyry copper deposits
Crustal magmatic controls on the formation of porphyry copper deposits
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DOI：
10.1038/s43017-021-00182-8
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发表时间：
2021-07
影响因子：
42.1
通讯作者：
Jung‐Woo Park;I. Campbell;M. Chiaradia;Hongda Hao;Cin-Ty A. Lee
中科院分区：
文献类型：
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作者：
Jung‐Woo Park;I. Campbell;M. Chiaradia;Hongda Hao;Cin-Ty A. Lee
斑岩矿床是一种大型、低品位的金属矿体，由源自下伏岩浆储层的热液形成。它们是重要的工业和社会的关键金属，如铜和金的主要来源。然而，形成经济级斑岩矿床所需的岩浆和氧化还原过程仍然知之甚少。在这篇综述中，我们讨论了在认识有利于在俯冲带形成斑岩型铜矿床的地壳岩浆条件方面的进展。幔源弧岩浆的亲铜金属丰度主要受部分熔融过程中地幔楔中残余硫化物相的数量和性质的调节。地壳厚度影响下地壳岩浆储层的寿命和硫化物饱和度历史。例如，在厚地壳中，长期的岩浆活动与含水和氧化演化岩浆增加了找矿潜力，而薄地壳由于晚期硫化物饱和而有利于高亲铜元素的富集。浅深度（<7 km）的流体溶出可能对提高金的沉淀效率起作用，因为不混溶的硫化物熔体作为亲铜金属的短暂储存并将其释放到矿石流体中。未来的研究应致力于确定长英质体系中的主要硫化物相，以确定它们在岩浆分化过程中对亲铜元素行为的影响。
Porphyry deposits are large, low-grade metal ore bodies that are formed from hydrothermal fluids derived from an underlying magma reservoir. They are important as major sources of critical metals for industry and society, such as copper and gold. However, the magmatic and redox processes required to form economic-grade porphyry deposits remain poorly understood. In this Review, we discuss advances in understanding crustal magmatic conditions that favour the formation of porphyry Cu deposits at subduction zones. Chalcophile metal fertility of mantle-derived arc magmas is primarily modulated by the amount and nature of residual sulfide phases in the mantle wedge during partial melting. Crustal thickness influences the longevity of lower crustal magma reservoirs and the sulfide saturation history. For example, in thick crust, prolonged magma activity with hydrous and oxidized evolving magmas increases ore potential, whereas thin crust favours high chalcophile element fertility, owing to late sulfide saturation. A shallow depth (<7 km) of fluid exsolution might play a role in increasing Au precipitation efficiency, as immiscible sulfide melts act as a transient storage of chalcophile metals and liberate them to ore fluids. Future studies should aim to identify the predominant sulfide phases in felsic systems to determine their influence on the behaviour of chalcophile elements during magma differentiation.