INVESTIGADORES
CARLINI Alfredo Armando
congresos y reuniones científicas
Título:
Paleogeography and paleoenvironments of Central Patagonia from the Late Cretaceous to the Miocene: The Paleogene Andean gap and the rise of the Northpatagonian Altiplano.
Autor/es:
ARAGÓN E., F. J. GOIN, Y. E. AGUILERA, M. O. WOODBURNE, A. A. CARLINI, M. F. ROGGIERO
Lugar:
LA PLATA
Reunión:
Workshop; Paleogeography and Paleoclimatology of Patagonia: effects on biodiversity; 2009
Institución organizadora:
FAC. CS. NATURALES Y MUSEO - DALHOUSIE UNIVERSITY
Resumen:
In its large expanse, the Andes comprise a barrier that affects in many ways the
distribution of climate in the region. From a geological perspective, the Andean
mountain system is a supra-subduction feature at the active South American plate
margin. This plate margin has been active since the Late Jurassic. The modern
configuration of the Andes and its large N-S variations are the result of post-Miocene
tectonic processes and the particular characteristics of each segment (subduction angle,
angle of convergence, thickness of the oceanic plate, relationships between the
segments, composition of the continental crust, etc.). For this reason, it is necessary to
review the pre-Miocene orogenic development and its potential regional geographic role
for each segment in particular and whether or not there was a marine connection
between the Atlantic and Pacific oceans. The northern Patagonian segment of the Andes
preserves a geotectonic history which differs from its neighbors in that it behaved as a
transcurrent margin during the Paleogene. This episode was characterized by extension,
with the evolution of forearc, arc, and backarc basins and the migration of calcalkaline
volcanism toward the backarc. The Andean uplifted segment was eroded and deactivated
and permitted the flow of humid air from the Pacific to the extra-Andean
regions. Simultaneously in the backarc region of this segment, the 1200-1500 m uplift
of the North Patagonian Massif took place, resulting in an Altiplano of 100,000 m2
which dominated the area during the Oligocene. It is estimated that the climate in the
Altiplano was humid, seasonally cool, in contrast to the seasonally more uniform humid
climates to the south.
The most important mammalian turnover that happened during the Paleogene
occurred at the early Oligocene, concurrently with the full opening of the Drake Passage
and the global cooling. The latitudinal climate gradient that began at the Eocene-
Oligocene transition affected sharply the whole Patagonian region, and at least at these
times the mammalian turnover affected the mammalian associations both East and West
of the Andean Range.
This work considers the possible changes in the geographic segments during the
Cenozoic for the Northern Patagonian region and their effect on climate control, as well
as a consideration of the principal sedimentary and magmatic cycles, global climatic
events and main faunal cycles.