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Turkish Journal of Earth Sciences

DOI

10.3906/yer-1802-13

Abstract

In this article, the petrological processes of the clinopyroxenite dykes and host peridotites occurring in Ulaş District (Sivas, mid-Anatolia, Turkey) are discussed. The new geochemical data from major minerals in the clinopyroxenite dykes and host harzburgites revealed differences to the supra-subduction zone (SSZ)-type pyroxenites and peridotites. In particular, the NiO content of olivines in the host harzburgites showed the signature of the mantle, whereas rare olivines of the clinopyroxenites had a NiO content and Fo number that were inferior to those of mantle peridotites. The high Mg-number of clinopyroxenes in the clinopyroxenites was likely associated with the partial remelting of the host harzburgites. Additionally, the rare earth element pattern of clinopyroxenes from the studied clinopyroxenites exhibited a similar pattern to those of the other SSZ or fore-arc clinopyroxenes. Additionally, the low Mgnumber and relatively high Cr-number of spinels in the clinopyroxenites showed similarity to the subduction-related origin. Based on textural and geochemical evidence, the harzburgites were interpreted as depleted mantle rock, which was modified by melt-peridotite interactions. Consequently, the pyroxenites likely occurred as a crystallizing or cumulative zone of the SSZ-type melt and the minerals were gained from partial melting of the harzburgites through the interaction with such magma.

Keywords

Pyroxenite dyke, peridotite, subduction zone, partial melting, Sivas, Turkey

First Page

384

Last Page

404

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