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DOI	10.1016/j.epsl.2020.116584
	The role of incremental magma chamber growth on ore formation in porphyry copper systems
	Korges M.; Weis P.; Andersen C.
发表日期	2020
ISSN	0012821X
卷号	552
英文摘要	Porphyry copper deposits are formed by fluids released from felsic magmatic intrusions of batholithic dimensions, which are inferred to have been incrementally built up by a series of sill injections. The growth of the magma chamber is primarily controlled by the volumetric injection rate from deeper-seated magma reservoirs, but can further be influenced by hydrothermal convection and fluid release. To quantify the interplay between magma chamber growth, volatile expulsion and hydrothermal fluid flow during ore formation, we used numerical simulations that can model episodic sill injections in concert with multi-phase fluid flow. To build up a magma chamber that constantly maintains a small region of melt within a period of about 50 kyrs, an injection rate of at least 1.3 x 10−3 km3/y is required. Higher magma influxes of 1.9 to 7.6 x 10−3 km3/y are able to form magma chambers with a thickness of 2 to 3 km. Such an intrusion continuously produces magmatic volatiles which can precipitate a copper ore shell in the host rock about 2 km above the fluid injection location. The steady fluid flux from such an incrementally growing magma chamber maintains a stable magmatic fluid plume, precipitating a copper ore shell in a more confined region and resulting in higher ore grades than the ones generated by an instantaneous emplacement of a voluminous magma chamber. Our simulation results suggest that magma chambers related to porphyry copper deposits form by rapid and episodic injection of magma. Slower magma chamber growth rates more likely result in barren plutonic rocks, although they are geochemically similar to porphyry-hosting plutons. However, these low-frequency sill injection events without a significant magma chamber growth can generate magmatic fluid pulses that can reach the shallow subsurface and are typical for high-sulfidation epithermal deposits. © 2020 Elsevier B.V.
关键词	magma chamber magmatic sill numerical modeling ore deposit pluton porphyry copper deposits
英文关键词	Copper deposits; Deposits; Ores; Epithermal deposits; Hydrothermal convection; Hydrothermal fluids; Magmatic intrusions; Magmatic volatiles; Multi-phase fluid flow; Porphyry copper deposits; Shallow subsurface; Flow of fluids; batholith; hydrothermal fluid; igneous intrusion; magma chamber; ore deposit; pluton; porphyry; sill
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202706
作者单位	GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Institute of Earth and Environmental Science, University of Potsdam, Potsdam, 14476, Germany
推荐引用方式 GB/T 7714	Korges M.,Weis P.,Andersen C.. The role of incremental magma chamber growth on ore formation in porphyry copper systems[J],2020,552.
APA	Korges M.,Weis P.,&Andersen C..(2020).The role of incremental magma chamber growth on ore formation in porphyry copper systems.Earth and Planetary Science Letters,552.
MLA	Korges M.,et al."The role of incremental magma chamber growth on ore formation in porphyry copper systems".Earth and Planetary Science Letters 552(2020).