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Intrusion age of Pan-African augen gneisses in the southern Menderes Massif and the age of cooling after Alpine ductile extensional deformation

Published online by Cambridge University Press:  01 May 2009

R. Hetzel  and
T. Reischmann
R. Hetzel
Affiliation:
Institut für Geowissenschaften, Johannes Gutenberg-Universität, 55099 Mainz, Germany
T. Reischmann
Affiliation:
Institut für Geowissenschaften, Johannes Gutenberg-Universität, 55099 Mainz, Germany Max-Planck-Institut für Chemie, Abteilung Geochemie, 55023 Mainz, Germany
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Abstract

Pb–Pb single zircon ages of 546.2 ± 1.2 Ma demonstrate that the augen gneisses in the southern Menderes Massif were generated from Pan-African intrusions. During the Alpine orogenic evolution of the Menderes Massif these granites were metamorphosed and transformed into augen gneiss in an extensional top-to-the-south shear zone, located between augen gneisses and overlying schists. Quartz fabrics suggest a pronounced static recrystallization that post-dates the ductile deformation in the shear zone. Ar–Ar muscovite ages of 43–37 Ma from augen gneisses and schists suggest that ductile deformation and subsequent cooling occurred in the Eocene. These results contradict previous models that (1) interpret the extensional shear zone as late Oligocene in age and (2) regard the augen gneisses as syntectonic with respect to ductile extensional deformation.

Type
Articles
Information
Geological Magazine , Volume 133 , Issue 5 , September 1996 , pp. 565 - 572
Copyright
Copyright © Cambridge University Press 1996

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