Deformation style change in the transition zone from mantel to crust: NW Khoy ophiolite


1 Associate professor in Geology Department at Urmia University

2 Geology department, Science faculty, Urmia university, Urmia, Iran


Ophiolite is a remnant part of oceanic crust and consist of the upper mantle and lower crust rock units. The transition from mantel to crust coincides with Moho discontinuity. Ophiolite rocks host valuable minerals for this discrimination of different parts of this unit is important. In the Khoy region for discrimination of different parts of ophiolite, rock units used various band ratio and principal component analyses. Structural analysis in both of micro-and-macro scales was applied to document change in deformation style in the Moho transition zone.
The results of this research indicated that remote sensing techniques such as band ratio and principal component analysis are effective tools for discriminating mantle harzburgite and dunite rock units from crust gabbro and basalt. The transition from mantel to crust is accompanied by structural style change. The mantle-related rock unit ductile shear zone with NW-SE trending were dominated structure and caused the propagation of amphibolite and mylonite rock unit. In this unit pyroxene minerals elongated and folded. With the transition to the crust brittle structure such as fault zone with NE-SE trending were dominated. The evidence in the study region Moho discontinuity is exposed in the two different distinct areas and may be related to different ophiolite generations.


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