2026-06-29T07:22:28Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/436842023-08-25T14:36:45Zcom_20.500.14352_14col_20.500.14352_15

Earthquake-induced soft-sediment deformation structures in Upper Jurassic open-marine microbialites (Neuquén Basin, Argentina) Martín Chivelet, Javier Palma, Ricardo Manuel López Gómez, José Kietzmann, Diego A. 551.763(828) Soft-sediment deformation Seismites Carbonate rocks Tithonian Back-arc basin Andes Geología estratigráfica 2506.19 Estratigrafía Penecontemporaneous decimetre-scale soft-sediment deformation structures are reported from the basal part of the Upper Jurassic–Lower Cretaceous Vaca Muerta Formation, in the Malargüe–Las Leñas area of the back-arc Neuquén Basin (Mendoza Province, Central Andes). The deformed interval (Amarillas bed) is only 0.3 to 0.9 m thick but occurs in a wide area, larger than 1500 km2. Its age, determined by ammonite biostratigraphy, is Early Tithonian. The soft-sediment deformation structures were generated in finely laminated, partially consolidated, organicrich, carbonate microbialites that were deposited in open-marine, poorly oxygenated settings, apparently devoid of any significant slope. Those structures include boudins of different sizes and complexity, a variety of folds, normal (listric) dm-scale faults, sub-horizontal detachment surfaces and other features, which are part of several larger-scale, complex slump structures. Deformation was dominantly plastic but near to the ductile–brittle field transition. On the basis of the observed soft-deformation structures, their geographic distribution, their lateral homogeneity, and the geodynamic framework of the basin in which it was generated, the Amarillas bed can be tentatively attributed to a large, intermediate-depth earthquake that occurred within the plate that subducted beneath the Andean continental margin and the Neuquén back-arc basin. Depto. de Geodinámica, Estratigrafía y Paleontología Fac. de Ciencias Geológicas TRUE pub 2023-06-20T03:31:07Z 2023-06-20T03:31:07Z 2011 journal article https://hdl.handle.net/20.500.14352/43684 0037-0738 10.1016/j.sedgeo.2010.09.017 eng open access application/pdf Elsevier