Regional transect across the Quirquincho High (NW Argentina)

CORTASSA, V., ROSSELLO, E.A., BACK, S., ONDRAK, R., AND STRECKER, M

Hamburgo

Simposio; 25th Latin-American Colloquium of Geoscience; 2019

25th Latin-American Colloquium of Geoscience

TheChaco-Pampean plain of the Argentine Andean foreland covers theChaco-Paranaense intracratonic basin (CPB) and the eastern portion of theCretaceous Salta Rift basin (SRB). At surface, there is no direct evidence fora complex tectonic history of this region. Subsurface data, however, document a rich geological history of magmaticepisodes, multiple tectonic events and sedimentation controlled by tectonics. TheQuirquincho Arch (also known as the Rincón-Caburé High) is an inheritedsubsurface structure characterized by a preferential NE-SW orientation. Thisstructure is an extensive and prominent basement ridge that constitutes theboundary between the CPB and the SRB. This orientation is also broadlyreflected by the overall trends of the adjacent Sierras Pampeanasbroken-foreland province, the Colonia-Aldao High and the Las Breñas depocenter.This study compiles and reviews available subsurface information from oilexploration, including borehole data, 2D seismic-reflection lines andtopographic data to reconstruct the tectono-sedimentary history along aregional NW-SE transect between Tartagal (Salta province) and Formosa city (Formosa province); key focus is theanalysis of the multi-episodic activity of the Quirquincho Arch. Tectonicactivity along the Quirquincho Arch is interpreted to have controlled thefacies distribution of syntectonic sequences in the two adjacent basins duringthe Paleozoic and Mesozoic. Theinterpretation of 2D seismic-reflection data and well-log information allowedto identify the subsurface position and shape of the Quirquincho Arch. Itspresence is unambiguously reflected on various seismic-reflection lines. Thearch is characterized by multiple reflection terminations at its top and flanks;the interpretation of onlaps and truncations enables the reconstruction of itstectonic history.The tectonicactivity and its consequence for the architecture of sedimentary units in bothsedimentary basins adjacent to the Quirquincho Arch have not been described indetail in literature nor by exploration of hydrocarbons. Nevertheless, thestructures generated by the tectonic activity of the Quirquincho Arch couldhave a major impact on the formation of stratigraphic traps that could storepetroleum formed in Paleozoic and Mesozoic source rocks.. From our evaluationsthe onlap, truncation and pinch out structures of sedimentary units towards theQuirquincho Arch are an interesting objective for future prospection forhydrocarbon accumulations.