Abstract
The Central Anatolian Crystalline Complex (CACC) is a microcontinent in the Alpine-Himalayan belt. It has previously been considered as a coherent structural entity, but, although the entire CACC is comprised of similar rocks (primarily metasedimentary rocks and granitoids), it consists of at least four tectonic blocks characterized by different P-T-t paths. These blocks are the Kirşehir (north-west), Akdaǧ (northeast), Niǧde (south) and Aksaray (west) massifs. The northern massifs experienced thrusting and folding during collision and were slowly exhumed by erosion; metamorphic rocks are characterized by clockwise P-T paths at moderate P-T and local low-P-high-T (LP-HT) overprinting in the highest grade rocks. Apatite fission track ages are Eocene to Oligocene (47-32 Ma). The Aksaray block represents the hot, shallow mid-crust of a Late Cretaceous-early Tertiary arc. It is dominated by intrusions; rare metapelitic rocks record low-P (<4 kbar) regional metamorphism overprinted by LP-HT contact metamorphism. Apatite fission track ages are 50-45 Ma. The Niǧde massif is different from the other CACC blocks because it evolved as a core complex in a wrench-dominated setting. It is characterized by clockwise P-T paths at moderate P-T followed by widespread LP-HT metamorphism. Apatite fission track ages are Miocene (12-9 Ma), significantly younger than those in the northern massifs. Niǧde rocks resided in the mid-crust at a time when the rest of the CACC was at or near the Earth's surface. Variations in P-T-t and tectonic histories-especially timing of exhumation - between the northern and southern CACC reflect the difference between head-on collision vs. mid-crustal wrenching.
Original language | English (US) |
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Pages (from-to) | 411-432 |
Number of pages | 22 |
Journal | Journal of Metamorphic Geology |
Volume | 19 |
Issue number | 4 |
DOIs | |
State | Published - 2001 |
Keywords
- Metamorphism
- Microcontinent collision
- P-T-t paths
- Turkey
- Wrench tectonics