The origin of high-Cu/S sulfides by shallow-level degassing in the Skaergaard intrusion, East Greenland

Published

Journal Article

© 2017 Geological Society of America. The Skaergaard intrusion of East Greenland is characterized by unusually low sulfur (S) and high metal/S ratios. Explanations range from S lost during cooling to suggestions that low S was characteristic of the original magma. A nonequilibrium thermodynamic analysis of modal variations in the chilled margin and Lower Zone is consistent with a late stage reaction of chalcopyrite → magnetite ± bornite + Slost; the pre-reaction assemblage was dominated by chalcopyrite with a Cu:S mass ratio ~1:1, a ratio unusually low for an undegassed hotspot basalt. A comparison with other hotspot and flood basalt provinces suggests that these magmas can lose significant S to recirculating shallow-level degassed magma. It is concluded that degassing of the parent Skaergaard magma prior to solidification and continuous vapor loss during crystallization both contributed to the overall high metal/S ratios of the Skaergaard system.

Full Text

Duke Authors

Cited Authors

  • Li, C; Boudreau, AE

Published Date

  • December 1, 2017

Published In

Volume / Issue

  • 45 / 12

Start / End Page

  • 1075 - 1078

Electronic International Standard Serial Number (EISSN)

  • 1943-2682

International Standard Serial Number (ISSN)

  • 0091-7613

Digital Object Identifier (DOI)

  • 10.1130/G39540.1

Citation Source

  • Scopus