Fault and fold interaction during the development of the Neogene-Quaternary Almería-Níjar basin (SE Betic Cordilleras)

Abstract

Abstract The Neogene-Quaternary Almería-Níjar basin includes the Carboneras Fault, which constitutes a major left-lateral feature of the Betic Cordilleras. New gravity data help to determine the geometry of the sedimentary infill. The region underwent NE-SW extension during the Tortonian and local NW-SE compression during the first stages of Sierra Alhamilla uplift. During the Messinian, the sinistral strike-slip motion along the Carboneras Fault Zone, the dextral strike-slip motion along NW-SE-oriented faults, and the development of large folds such as the Sierra Alhamilla antiform, suggest clockwise rotation (towards the north) of the maximum stress axis (σ 1 ). During the Pliocene, a NNW-SSE-oriented compression also contributes to fold development. Finally, during the Quaternary, an ENE-WSW-directed extension controls the development of NW-SE-oriented normal oblique faults. The most recent local normal activity of the Carboneras Fault is related to this extension, whereas its behaviour as a left-lateral strike-slip fault may be a consequence of the accommodation of NW-SE normal fault displacements. Basic rock bodies, recognized by means of a detailed study of the magnetic anomalies, are related to the volcanic activity known to have occurred in the area in Late Miocene times.