Oxidized sulfur-rich arc magmas formed porphyry Cu deposits by 1.88 Ga

Meng, Xuyang; Kleinsasser, Jackie M.; Richards, Jeremy P.; Tapster, Simon R.; Jugo, Pedro J.; Simon, Adam C.; Kontak, Daniel J.; Robb, Laurence; Bybee, Grant M.; Marsh, Jeffrey H.; Stern, Richard A.. 2021 Oxidized sulfur-rich arc magmas formed porphyry Cu deposits by 1.88 Ga. Nature Communications, 12 (1), 2189. 10.1038/s41467-021-22349-z

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Official URL: http://dx.doi.org/10.1038/s41467-021-22349-z

Abstract/Summary

Most known porphyry Cu deposits formed in the Phanerozoic and are exclusively associated with moderately oxidized, sulfur-rich, hydrous arc-related magmas derived from partial melting of the asthenospheric mantle metasomatized by slab-derived fluids. Yet, whether similar metallogenic processes also operated in the Precambrian remains obscure. Here we address the issue by investigating the origin, fO2, and S contents of calc-alkaline plutonic rocks associated with the Haib porphyry Cu deposit in the Paleoproterozoic Richtersveld Magmatic Arc (southern Namibia), an interpreted mature island-arc setting. We show that the ca. 1886–1881 Ma ore-forming magmas, originated from a mantle-dominated source with minor crustal contributions, were relatively oxidized (1‒2 log units above the fayalite-magnetite-quartz redox buffer) and sulfur-rich. These results indicate that moderately oxidized, sulfur-rich arc magma associated with porphyry Cu mineralization already existed in the late Paleoproterozoic, probably as a result of recycling of sulfate-rich seawater or sediments from the subducted oceanic lithosphere at that time.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1038/s41467-021-22349-z
ISSN:	2041-1723
Date made live:	28 Jun 2021 11:42 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/530572

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1038/s41467-021-22349-z

ISSN:

2041-1723

Date made live:

28 Jun 2021 11:42 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/530572