INVESTIGADORES
DEL PAPA Cecilia Eugenia
artículos
Título:
Middle Eocene deformation-sedimentation in the Luracatao Valley: Tracking the beginning of the foreland basin of Northwestern Argentina
Autor/es:
PAYROLA BOSIO, P; POWELL, J; DEL PAPA C; HONGN, F.
Revista:
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2009 vol. 28 p. 142 - 154
ISSN:
0895-9811
Resumen:
The Andean foreland basin overlaps the Cretaceous-Paleogene Salta rift basin in northwestern Argentina.
Knowledge of the relationship between rift and foreland basins is key to understanding the initial stages
of foreland basin development related to Andean shortening. We present a new stratigraphic scheme for
the Luracatao Valley, revealing that the Quebrada de los Colorados Formation (Payogastilla Group) lies
over the Santa Bárbara Subgroup (Salta Group) through an erosional unconformity that turns into an
angular unconformity close to folds and faults recorded in the Santa Bárbara Subgroup. The base of the
Quebrada de los Colorados Formation shows growth strata along the west frontal limb of an anticline
with Santa Bárbara units in its core. The finding of a mammalian fossil at the base of the Quebrada de
los Colorados Formation allows us to assign a Middle-Upper Eocene age to the sedimentation; therefore,
the time elapsed between the deposition of the final postrift strata and the beginning of Andean sedimentation
was brief and constrained to the Lower-Middle Eocene. This data indicates that the Eocene deformation
phase described in other portions of the Puna-Cordillera Oriental transition (e.g., the northern
Calchaquí Valley and Aguilar range) is also present in the Luracatao Valley, offering new tools for interpreting
the ages and distributions of the initial episodes of sedimentation and deformation related to the
Andean shortening. Thus, the Luracatao Valley provides new evidence for tracking the distribution of the
Paleogene deformation in northwestern Argentina.