Comparison of strain ellipsoid shape based on the results of the magnetic susceptibility anisotropy and paleostress methods: Case study of Aksu basin (SW Turkey)

Aksu Basin is the marine sedimentary basin located in the center of the Isparta Angle (SW Turkey). Its structures and geometry may provide very useful information about Miocene crust deformation and stress field in the region. In this study, it is aimed to determine main paleostress directions (σ1, σ2, σ3) that have been effective in the Aksu Basin. For this purpose, more than 1000 fault-slip measurements from the mesoscopic faults were collected at the 83 different sites. The results demonstrate that the Aksu Basin developed under four different tectonic phases; 1) ~E-W extensional phase, 2) ~N-S compressional (Lycian) phase, 3) ~E-W compressional (Aksu) phase and 4) N-S extensional Neotectonic phase. In order to test fault-slip data independently, ~490 oriented samples for Anisotropy of Magnetic Susceptibility (AMS) measurements were collected and analyzed. The results of the AMS data show that two different magnetic lineations (Kmax) directions are present. These are 1) N-S magnetic lineation in Pliocene and 2) from N-S to NW-SE magnetic lineation in the Miocene. This study shows that AMS data are consistent with kinematic observations and provide independent information for understanding of the deformation pattern in the Aksu Basin. Based on the AMS data, Recent phase can be differentiated from the rest of the data. AMS data can be evidently used help to construct the paleostress stratigraphy. Key words: Aksu Basin, Anisotropy of Magnetic Susceptibility (AMS), Paleostress inversion.