F, Cl and S input via serpentinite in subduction zones: implications for the nature of the fluid released at depth. (17th October 2013)

• Record Type: Journal Article
• Authors: Debret, Baptiste; Koga, Kenneth T.; Nicollet, Christian; Andreani, Muriel; Schwartz, Stéphane
• Is Part Of: Terra nova. Volume 26:Number 2(2014:Apr.)
• Page Start: 96
• Page End: 101
• Publication Date: 2013-10-17
• Subjects: Earth sciences -- Periodicals; Geology -- Periodicals; 550
• DOI: 10.1111/ter.12074
• Languages: English
• ISSNs: 0954-4879

Abstract

<abstract abstract-type="main" id="ter12074-abs-0001"> <title>Abstract</title> <p>The abundances of F, Cl and S in arc magmas are systematically higher than in other mantle‐derived magmas, suggesting that these elements are added from the slab along with H₂O. We present ion probe microanalyses of F, Cl and S in serpentine minerals that represent the <italic>P–T</italic> evolution of the oceanic lithosphere, from its serpentinization at the ridge, to its dehydration at around 100 km depth during subduction. F, Cl and S are incorporated early into serpentine during its formation at mid‐ocean ridges, and serpentinized lithosphere then carries these elements to subduction zones. More than 50% of the F, Cl and S are removed from serpentine during the prograde metamorphic lizardite/antigorite transition. Due to the low solubility of F in water, and to the low amount of water released during this phase transition, the fluids mobilizing these elements must be dominated by SO_X rather than H₂O.</p> </abstract>