GEOCHEMISTRY AND TECTONIC SIGNIFICANCE OF AUGEN GNEISSES FROM THE SOUTHERN MENDERES MASSIF (WEST TURKEY)


BOZKURT E. , WINCHESTER J., PARK R.

GEOLOGICAL MAGAZINE, vol.132, no.3, pp.287-301, 1995 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 132 Issue: 3
  • Publication Date: 1995
  • Doi Number: 10.1017/s0016756800013613
  • Title of Journal : GEOLOGICAL MAGAZINE
  • Page Numbers: pp.287-301

Abstract

The protoliths of mylonitized augen gneisses exposed in the southern sector of the Menderes Massif (West Turkey) are calc-alkaline, peraluminous, S-type, late- to post-tectonic tourmaline- and garnet-bearing, two-mica leucogranites. They cut and post-date the fabrics of the 'main Menderes metamorphism' which took place between the early Eocene and early Oligocene and intrude metamorphic basement rocks comprising the so-called 'Palaeozoic schist envelope' of the massif. They are themselves cut by an extensive network of tourmaline-rich dykes. Chemical, mineralogical, isotopic and field relations suggest that the granitic protolith crystallized from a boron-rich, water-saturated melt, derived from partial melting of metagreywacke in the lower crust during peak Barrovian-type metamorphism. The protolith was probably emplaced during lateorogenic extensional collapse of the thickened crust in west Turkey during late Oligocene time.