Origin and evolution of lago yehuin (Tierra del fuego, Argentina): Results from a geophysical survey

Lago Yehuin, a WNW-ESE elongated basin located in the outer fold-and-thrust belt of the Fuegian Andes, occupies a compartmented structural depression originated along a segment of the left-lateral Lago Deseado fault system. This paper describes the first geophysical survey performed within the lake....

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Detalles Bibliográficos
Autores principales: Lozano, J.G., Tassone, A., Lodolo, E., Menichetti, M., Cerredo, M.E., Bran, D.M., Esteban, F., Ormazabal, J.P., Baradello, L., Vilas, J.F.
Formato: JOUR
Materias:
Fuegian andes
Lago yehuin
Single-channel seismic profiles
Strike-slip tectonics
data interpretation
fold and thrust belt
geophysical survey
lake
seismic data
seismic stratigraphy
seismic survey
strike-slip fault
structural control
structural geology
tectonic evolution
tectonic setting
Andes
Argentina
Tierra del Fuego [(PRV) Argentina]
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_07187092_v45_n3_p318_Lozano
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:Lago Yehuin, a WNW-ESE elongated basin located in the outer fold-and-thrust belt of the Fuegian Andes, occupies a compartmented structural depression originated along a segment of the left-lateral Lago Deseado fault system. This paper describes the first geophysical survey performed within the lake. New acquired high-resolution single-channel seismic data, integrated with geological information in the surroundings of the Lago Yehuin, allowed to: (i) produce a complete bathymetric map of the lake, (ii) reconstruct the basement surface of the lake, and (iii) analyze the geometry, distribution, and thickness of the sedimentary infill. Two sub-basins were recognized within Lago Yehuin: A western sub-basin, 7.5 km long, with a maximum depth of 118 m; an eastern sub-basin, 7.2 km long with a maximum depth of 80 m. Both sub-basins are limited by a set of normal faults which overprint NE-verging thrusts. Three seismo-stratigraphic units have been identified in the seismic records: (1) a lower unit with wedged geometry interpreted as a mass flow deposits; (2) a thick (up to 120 m) intermediate unit of glacio-lacustrine nature and irregularly distributed in the Yehuin basin; (3) a thin (generally <10 m) upper lacustrine unit which drapes the entire basin. Lago Yehuin is considered a Neogene basin generated by strike-slip tectonics that was later affected by glacial and glacio-lacustrine deposition. Interpreted submerged ridge moraines within Lago Yehuin are correlated with onland moraine arcs built by the complete recessional paths of Fuego and Ewan ice lobes. A significant structural control is proposed not only for the formation of Lago Yehuin, but also for the general paths of the northern arms of the Fagnano palaeo-glacier. © 2018, Servicio Nacional de Geologia y Mineria. All rights reserved.

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