Journal of Petrology, Volume 39, Issue 7: July 1 1998.

Metamorphism during Alpine Crustal Thickening and Extension in Central Anatolia, Turkey: the Nig[breve]de Metamorphic Core Complex

D. L. WHITNEY¹ AND Y. DILEK²

¹DEPARTMENT OF GEOLOGY AND GEOPHYSICS, UNIVERSITY OF MINNESOTA, MINNEAPOLIS, MN 55455, USA ²DEPARTMENT OF GEOLOGY, MIAMI UNIVERSITY, OXFORD, OH 45056, USA

RECEIVED DECEMBER 23, 1996; REVISED TYPESCRIPT ACCEPTED FEBRUARY 12, 1998

The Nig[breve]de massif, a metamorphic core complex in Central Anatolia (Turkey), contains petrologic evidence for the transition from Alpine crustal thickening to extension and exhumation of high-grade mid-crustal rocks. Sillimanite-potassium feldspar gneiss formed and partially melted during Barrovian metamorphism and records maximum conditions of 5-6 kbar, >700°C. The two-mica Üçkaplll granite and a related dike suite intruded the migmatitic metapelitic rocks, forming a contact aureole that contains andalusite and cordierite. These low-pressure minerals indicate that crustal thickening was followed by exhumation of mid-crustal rocks to relatively shallow depths (<10 km) at lower temperatures before the emplacement of granitic magma. Formation of andalusite was followed by a second, prograde episode of sillimanite growth during low-pressure-high-temperature metamorphism in the central part of the massif, where magmatism was most extensive. A generalized P-T path for the highest grade rocks therefore consists of an initial clockwise path with a late thermal spike and characterizes burial and subsequent exhumation accompanied by magmatism.

Keywords: Barrovian;metamorphic core complex;metapelitic rocks; P-T path; Turkey

Pages 1385-1403

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