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Enhancing imaging of the Sub‐Andean Foothills geology using magnetotellurics: A case history of a 3D survey in southern Bolivia
Author(s) -
Pezzoli Mauro,
Lazaro Evanz,
Cuevas Nestor,
Burga Sergio
Publication year - 2020
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/1365-2478.12944
Subject(s) - foothills , geology , magnetotellurics , inversion (geology) , paleontology , regional geology , palaeogeography , environmental geology , sinistral and dextral , structural geology , paleozoic , foreland basin , seismology , tectonics , telmatology , volcanism , cartography , geography , electrical engineering , engineering , electrical resistivity and conductivity
A magnetotelluric acquisition and modelling campaign, comprising 400 full tensor soundings, was carried out in the Sub‐Andean Foothills in the area located south of Santa Cruz de la Sierra, Bolivia. The objective of the survey was to improve the imaging of the Paleozoic section and provide insight to the overall structure of the Devonian Silurian complex. The acquired data were inverted assuming both two‐dimensional and three‐dimensional dimensionality of the subsurface structure, adopting a multi‐step iterative workflow, which began applying unconstrained inversion and introduced increasing constraints determined at each following step based on the interpretation of the latest inversion results. The geological interpretation of the final inversion results allowed to better image the expected complexity in the structures, particularly highlighting several different levels of detachment, mainly in the area of Kirusillas Formation. Furthermore, an oblique sense was identified of the main tendency of N‐S deformation, related to a dextral transgressional movement that generates discrete dislocations, at a length scale of the order of a few kilometres.