Abstract

MARTINEZ, Oscar Alfredo. Unidades gravitacionales en los alrededores de Esquel: clasificacion, origen y edad. Rev. Asoc. Geol. Argent. [online]. 2016, vol.73, n.3, pp.319-329. ISSN 0004-4822.

The main landslide units located on the slopes of the Esquel and the Percey river valleys (northwest of Chubut province, Argentina) have been studied. The mass wasting processes include, essentially, debris flows and rotational slides. They mobilized Tertiary sedimentary rocks and Pleistocene glacigenic deposits. The landslides units that lie in the Esquel valley were originated after the withdrawal of the glaciers at the end of the Last Glaciation and, at least some of them, were coeval with the glaciolacustrine basin generated during the glacier melting. The units located in the Percey river valley are younger, since they are placed to the west of remains of a post-Last Glaciation drift. The main conditioning factors favoring these landslides have been the high porosity and low cohesion of the sedimentary rocks cropping out. The main triggering factor would have been the relaxation of the slopes after the melting of the glaciers. However, in some cases, the fluvial incision may have played a significant role. More than half of the studied units are totally or partially urbanized or affected by the construction of roads and, eventhough all these features are considered as non-active landforms, some of these human interventions are already reactivating these landslides and thus putting property and people at risk.

Keywords : Mass wasting; Post-glacial; Glaciolacustrine; Chubut.

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