![]() ![]() The enrichment of incompatible trace elements has been attributed to the addition of a subduction component to the mantle wedge however, the nature of this subduction component and its means of addition remain under debate. Our findings suggest that slab melt is primarily responsible for element recycling to the arc.Īrc basalt has a major element composition similar to mid-oceanic ridge basalt (MORB) and ocean island basalt, but distinctive trace element characteristics, such as enrichment in large ion lithophile elements (LILEs e.g., Rb, Cs, Ba, Sr, and Pb), light rare earth elements (LREEs e.g., La and Ce), Th, U, and depletion in high field strength elements (HFSEs e.g., Nb, Ta, Zr, and Hf). In particular, the systematic correlation of element ratios in arc basalt corresponds to element fractionation in slab melt with temperature and therefore follows a power function. We observe that variation of element ratios in global primitive arc basalts is comparable with that of sediment and/or oceanic crustal melt, rather than (saline) aqueous fluid or mélange melt. Here, we present experimental data for near-solidus sediment melts and a framework for calculating trace element concentrations in subduction fluids from metamorphosed sediment and oceanic crust. The long-standing model of element recycling through aqueous fluid from altered oceanic crust (AOC) and sediment melt has been challenged by the resurgence of mélange diapir (a mix of AOC, sediment, and serpentinite) and saline aqueous fluid models. ![]() Arc magma acquires continental crust-like trace element signatures through selective recycling of incompatible elements from the subducted slab. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |