Structural styles of the Aras fault zone with implications for a transpressive fault system in NW Iran

Saber R., IŞIK V., Caglayan A.

JOURNAL OF ASIAN EARTH SCIENCES, vol.207, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 207
  • Publication Date: 2021
  • Doi Number: 10.1016/j.jseaes.2020.104655
  • Journal Name: JOURNAL OF ASIAN EARTH SCIENCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Artic & Antarctic Regions, Geobase, INSPEC
  • Keywords: Fault geometry, Kinematic indicator, Paleostress analysis, Strain partitioning, Active tectonics, Turkish-Iranian Plateau, ARABIA-EURASIA COLLISION, PRESENT-DAY KINEMATICS, ALPINE-HIMALAYAN BELT, NORTH TABRIZ FAULT, TECTONIC EVOLUTION, ACTIVE TECTONICS, STRIKE-SLIP, GREATER CAUCASUS, STRESS PATTERN, EASTERN TURKEY
  • Ankara University Affiliated: Yes

Abstract

Aras Fault Zone (AFZ) is one of the most important intra-plate fault zones within the Turkish-Iranian Plateau. The AFZ is divided into five fault branches based on geometrical and structural properties called the Aras Main, Horadiz, Khodafarin, Asadkandi, and Aslanduz fault branches. Our geometric and kinematic analysis indicates that these faults exhibit compressional left-lateral strike-slip fault characteristics with general directions of NESW and dipping to SE. Structural mapping has revealed that the NE section of the AFZ shows typical horsetail fault geometry. Few meters to approximately 17 km of left-lateral displacements were observed along the AFZ, indicating the occurrence of numerous historical earthquake events. Paleostress analysis of fault slip data reveals that the AFZ has developed in the dominant NNE-SSW and NE-SW oriented compressional stress regime. Evaluating the Ratio of Principal Stress Differences (R), Stress Regime Index (R'), and principal stress directions show that the zone is under the transpressional tectonic regime. Paleostress orientations are consistent with orientations of the GPS velocity vectors, which indicates that the region, including the AFZ, is under the effect of the same tectonic regime, at least since Pliocene.