Çamlıca High (South of Soma, Manisa): An important structure to understand the Neogene-Quaternary tectonics of the Central Western Anatolia

E–W and N–S- trending cross grabens and horsts are the most important structures of Western Anatolia. Çamlıca High is a ~N–S-trending geomorphologic feature with a strong topographical manifestation. This feature, located at the northern tip of the Miocene Yuntdağı Volcanic Complex, is surrounded by Kırkağaç Graben to the east, Soma Graben to the north and Bakırçay Graben to the west. N–S- trending Kırkağaç Fault, E–W- trending Soma Fault and NE–SW-trending Kozanlı Fault set are the marginal faults of this structure. The lignite bearing deposits of N–S- trending Mio–Pliocene basin were elevated by these faults. These deposits and interior part of the High were also dissected by ~N–S and NW–SE- trending faults. To understand the tectonics of the region, field studies were carried out along the marginal structures and interior of the Çamlıca High. Based on the kinematic analyses, performed by using fault-slip data acquired from fault surfaces, the following results were obtained: i) NE–SW- trending faults have been formed under NW–SE extension and the principal stress distribution is σ1= 278°/78°, σ2= 63°/10° and σ3= 155°/7° and the value Φ is 0.184; ii) NW–SE- trending faults have been formed under NE–SW extension regime and the principal stress distribution is σ1= 154°/76°, σ2= 305°/12° and σ3= 37°/6° and the value Φ is 0.335; iii) for the formation of N–S- trending faults (Kırkağaç Fault), ENE–WSW extension is dominant. The principal stress distribution is σ1= 334°/47°, σ2= 187°/34°, σ3= 91°/23° and the value Φ is 0.609, and σ1= 166°/81°, σ2= 335°/9°, σ3= 65°/2° and the value Φ is 0.3 respectively. Under the light of these kinematic analyses, we can conclude that in the region two different tectonic regimes were revealed. The first one is NNE–SSW directed extensional regime resulted from WNW–ESE- trending compression. This tectonic regime was played an important role during the formation of N–S directed left lateral strike-slip faults with normal dip-slip component. The NW–SE- striking faults with normal dip-slip component and related oblique faults were formed due to extension in this regime. The last tectonic regime affecting the region is NNE–SSW and WSW–ENE directed simultaneous extension which enabled the formation of approximately N–S-trending normal faults (Kırkağaç Fault) and E–W-trending normal faults (Soma Fault) controlling especially the boundary of Çamlıca High. This regime additionally reactivated older faults within the region.