INVESTIGADORES
ASTINI Ricardo Alfredo
artículos
Título:
Volcanic controls on sedimentation in retroarc foreland basins: a case from Mio-Pliocene volcaniclastic deposits of Famatina (28º40´S), Argentina, southern Central Andes.
Autor/es:
MARTINA F.; DÁVILA F.M.; ASTINI, R A.
Revista:
SEDIMENTARY GEOLOGY
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2006 vol. 186 p. 51 - 65
ISSN:
0037-0738
Resumen:
A well-constrained record of MiocenePliocene explosive volcanism is preserved within the broken foreland of Western
Argentina along the Famatina Ranges. This paper focuses on the volcaniclastic record known as the Rý´o Blanco member of the El
Durazno Formation. Three facies can be recognized in the study area: (1) massive tuffs; (2) volcaniclastic conglomerates and (3)
pumiceous sandstones. These facies are interpreted as primary pyroclastic flow deposits (ignimbrites) and reworked volcanogenic
deposits within interacting volcanicfluvial depositional systems. Alternation between ignimbrites and volcanogenic sandstones
and conglomerates suggest a recurrent pattern of sedimentation related to recurrent volcanic activity. Considering the facies mosaic
and relative thicknesses of facies, short periods of syn-eruption sedimentation (volcaniclastic deposits) seem to have been separated
by longer inter-eruption periods, where normal stream-flow processes were dominant. The volcaniclastic component decreases upsection,
suggesting a gradual reduction in volcanic activity. The mean sedimentation rate of the Rý´o Blanco member is higher (0.44
mm/year) than those obtained for the underlying and overlying units. This increase cannot be fully explained by foreland basement
deformation and tectonic loading. Hence, we propose subsidence associated with volcanic activity as the causal mechanism.
Volcanism would have triggered additional accommodation space through coeval pyroclastic deposition, modification of the stream
equilibrium profile, flexural loading of volcanoes, and thermal processes. These mechanisms may have favored the preservation of
volcaniclastic beds in the high-gradient foreland system of Famatina during the MioPliocene. Thus, the Rý´o Blanco member
records the response of fluvial systems to large, volcanism-induced sediment loads.