Andalusite–sillimanite–quartz veins as indicators of low-pressure–high-temperature deformation during late-stage unroofing of a metamorphic core complex, Turkey |
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Authors: | Whitney & Dilek |
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Affiliation: | Department of Geology &Geophysics, University of Minnesota, Minneapolis MN 55455, USA, (email:;), Department of Geology, Miami University, Oxford OH 45056, USA |
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Abstract: | Ductilely deformed veins consisting of quartz+andalusite, in which the andalusite is partially replaced by fibrous sillimanite, locally occur in garnet–sillimanite schist near a margin of the Ni?de metamorphic core complex in south-central Turkey. Mineral assemblages, reaction textures and structural features of the veins record low-pressure–high-temperature deformation during exhumation of mid-crustal rocks. The partial replacement of andalusite by sillimanite may indicate a late-stage increase in temperature and/or fluid pressure, possibly related to Miocene magmatism, during extensional unroofing of the core complex. Aluminosilicate-bearing veins are observed at the eastern margin of the massif where metapelitic rocks were deformed during unroofing of the core complex. Veins formed in aluminous rocks where deformation-enhanced permeability allowed fluid flow during extensional shear. The cm-scale veins are typically boudinaged and form asymmetric lenses concordant with the host rock foliation and are parallel to the down-dip lineation defined by sillimanite and stretched biotite. Aluminosilicate-bearing boudins record top-to-the-east shear sense, which is compatible with the extensional shear sense displayed by structures in the host rock. |
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Keywords: | andalusite core complex sillimanite Turkey veins |
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