| Paper No. 79-15 | ||
| Presentation Time: 11:45 AM-12:00 PM | ||
| IN SITU TIMING CONSTRAINTS FROM THE MENDERES MASSIF, WESTERN TURKEY | ||
|
CATLOS, E.J., School of Geology, Oklahoma State Univ, 105 Noble Research Center, Stillwater, OK 74078, catlos@okstate.edu, ÇEMEN, Ibrahim, School of Geology, Oklahoma State Univ, Stillwater, OK 74078, ISIK, Veysel, Dept. of Geol., Eng, Ankara Univ, 06100, Ankara, Turkey, and SEYITOGLU, Gürol, Dept. of Geol. Eng, Ankara Univ, 06100, Ankara, Turkey The Aegean extended terrane of southeastern Europe contains the Cycladic and its eastern continuation, the Menderes Massif, in western Turkey. Although the metamorphic core complex origin of the Menderes Massif is well accepted, its metamorphic history has remained relatively unstudied. The massif exposes a 60000 km2 area of polymetamorphic rocks, which were subjected to compression followed by extension, and a graben system continues to deform the massif today. Numerous reported ages support a polyphase deformation history of the massif, but their link to the nature of specific events remains difficult and controversial. Problematic aspects include distinguishing Pan-African deformation from Alpine tectono-metamorphic evolution, and discriminating Eocene/Oligocene compression from recent extension. To decipher the chronology, monazite in garnet-bearing rocks from Menderes Massif’s northern, central, and southern sections were dated in situ using the Th-Pb ion microprobe method. Menderes Massif garnets were also element mapped as garnets commonly show zoning that reflects growth events or diffusional modification, providing information about the integrated thermal history of the sample. Menderes monazite ages are rarely consistent with a single population, and inclusions in garnet are typically older than matrix grains. For example, a northern rock 59-19/124b has three monazite inclusions in garnet that average 37.9±0.9 Ma (1s), whereas a matrix grain is 32.8±0.5 Ma. Matrix monazites in northern sample 30 are Miocene to Eocene. A growth-zoned garnet in northern rock 01-26 has a 36.0±0.6 Ma inclusion, but matrix monazites range from 28.2±0.4 Ma to 41.4±1.3 Ma. Matrix zircons from northern massif sample 01-13 are Pan African (207Pb/208Pb 508±92 Ma). More recent deformation events failed to erase all traces of this pre-Alpine evolution, as Pan African monazites in garnet are found in central sample 01-88 (498±8 Ma) and southern sample 01-141 (499±18 Ma). Garnets in 01-88 are diffusionally homogenized, and 01-88 matrix monazites in reaction with allanite yield 17±5 Ma and 4.5±1.0 Ma. As 01-88 was collected along a detachment surface, the monazite ages suggests the structure actively exhumed rocks from deep crustal depths (minimum 400°C) since the Pliocene. | ||
|
2002 Denver Annual Meeting (October 27-30, 2002)
| ||
| Session No. 79 Extensional Tectonics in the Southern Basins and Ranges, United States, and in Western Turkey Colorado Convention Center: C207 8:00 AM-12:00 PM, Monday, October 28, 2002 | ||
© Copyright 2002 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions. | ||