Geophysical evidence for the North Pie de Palo Lineament in the Precordillera

Abstract

The Precordillera fold-thrust belt, situated within the Pampean flat-subduction segment (27°–33°S), is characterised by enigmatic transversal structures which extend and influence deformation patterns, the full extent of which is yet to be fully elucidated. The Northern Pie de Palo Lineament represents a key example, and has been proposed to play a pivotal role in the development and structural control of the Precordillera. In any case, this lineament has not been subjected to a comprehensive study, which has led to ongoing debate regarding its structural control, persistence, and morphology. This study was therefore focused on this structure, employing multiple geophysical methodologies, including aeromagnetic and gravimetric techniques. This approach enabled the first visualization of the full extension and fault zone of the North Pie de Palo Lineament, which crosses the entire Precordillera fold-thrust belt in a transverse direction. Consequently, it can be posited that this structure would have exerted a conditioning influence on the thermo-mechanical state of the Andean lithosphere, enabled the uplift of mafic bodies and thus influenced the Neogene deformation of the Precordillera fold and thrust belt. The confirmation and characterization of this major structure open new perspectives on the interaction of deep-seated transversal structures with fold belts during the evolution of the southern central Andes.