Мақола

Copper Systematics in Arc Magmas and Implications for Crust-Mantle Differentiation

Cin‐Ty A. LeeDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USAPéter LuffiDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USAEmily J. ChinDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USARomain BouchetDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USARajdeep DasguptaDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USADouglas M. MortonDepartment of Earth Sciences, University of California Riverside, 900 University Avenue, Riverside, CA 92521, USAV. Le RouxDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USAQing‐Zhu YinDepartment of Geology, University of California, Davis, CA 95616, USADaphne JinDepartment of Earth Science, Rice University, MS-126, 6100 Main Street, Houston, TX 77005, USA

2012en

ABI

Аннотация

Arc magmas are important building blocks of the continental crust. Because many arc lavas are oxidized, continent formation is thought to be associated with oxidizing conditions. On the basis of copper's (Cu's) affinity for reduced sulfur phases, we tracked the redox state of arc magmas from mantle source to emplacement in the crust. Primary arc and mid-ocean ridge basalts have identical Cu contents, indicating that the redox states of primitive arc magmas are indistinguishable from that of mid-ocean ridge basalts. During magmatic differentiation, the Cu content of most arc magmas decreases markedly because of sulfide segregation. Because a similar depletion in Cu characterizes global continental crust, the formation of sulfide-bearing cumulates under reducing conditions may be a critical step in continent formation.

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DOI: 10.1126/science.1217313

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