Abstract

DI TOMMASO, Inés. Los flujos mantiformes inflados del campo volcanico Llancanelo. Rev. Asoc. Geol. Argent. [online]. 2016, vol.73, n.3, pp.430-440. ISSN 0004-4822.

The western sector of Llancanelo volcanic field (central south of Mendoza province) located west of the homonymous lagoon among Jarilloso and Trapal hills exposes a landscape of basaltic pahoehoe flows with a variety of landforms, very similar to those of the coastal plains of Hawaii and Iceland described as inflated pahoehoe sheet flows of several square kilometers, associated with other smaller forms such as lava rise and tumuli. Its formation depends essentially by exogenous primary features as the slope of the terrain and endogenous like viscosity and effusion rate or volume of lava extruded per time unit. In the work area inflated sheet flows 1-5 km long and up to 1 km wide, with sub-horizontal top surface or plateau bounded by steep escarpments were recognized. Overall most of them rise 2-7 m above the surrounding terrain, although they have been measured differences of height up to 25 meters. They consist of several flow units stacked 30-40 cm thick with abundant vesicles, which increase in diameter toward the top of each unit. In both the field and the images it is observed how toes of a basaltic flow progress by a steady supply of lava emission, first to isolated tumuli then by coalescence to lava rise and finally to inflated sheet flows.

Keywords : Pahoehoe lava; Lava rise; Tumuli; South central Mendoza.

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