INVESTIGADORES
MARSICANO Claudia Alicia
artículos
Título:
Tectono-sequence stratigraphy and UPb zircon ages of the Rincón Blanco Depocenter, northern Cuyo Rift, Argentina
Autor/es:
BARREDO, SILVIA; CHEMALE, FARID; MARSICANO, CLAUDIA; OTTONE, EDUARDO; RAMOS, VICTOR
Revista:
GONDWANA RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2012 vol. 21 p. 624 - 636
ISSN:
1342-937X
Resumen:
Extensional processes that followed the Gondwanan Orogeny rise to the development of a series of rift basins
along the continental margin over older accreted Eopaleozoic terranes. Stratigraphic, structural, paleontological,
and isotopic studies are presented in this work in order to constrain the ages of the sedimentary
infilling and to analyze the tectosedimentary evolution of one of the Cuyo basin depocenters, known as Rincón
Blanco. This asymmetrical half-graben was filled by continental sediments under a strong tectonic control.
The infilling was strongly controlled by tectonics which in term produced distinctive features along the whole
sedimentary sequence. Using a combination of lithological and structural data the infilling was subdivided
into packages of genetically linked units bounded by regional extended surfaces. Several tuffs and acid
volcanic rocks have been collected across the whole section of the Rincon Blanco sub-basin for SHRIMP and
LA-MC-ICPMS UPb zircon dating. The ages obtained range from 246.4±1.1 Ma to 230.3±1.5 Ma which is
the time elapsed for the deposition of three tectono-sequence units separated by regional unconformities and
mainly constrained to the Middle Triassic. They are interpreted as a result of a reactivation of the extensional
system that has evolved along strike as segments of faults that linked together and/or as laterally propagating
faults. Regional correlation with coeval rift basins permits to establish north-south propagation in the
extensional regime along the western margin of SW Gondwana. This trending started in the lowermost
Triassic and extended until the latest Triassic. Two of them were precisely correlated with Cerro Puntudo and
Cacheuta half-graben systems. The new data indicate that the three sequences were mostly deposited during
the Middle Triassic (246 to 230 Ma), with no evidence of sedimentation during Norian and Rhaetian, which is
in conflict with some previous biostratigraphic studies.