INVESTIGADORES
TABOADA Arturo Cesar
congresos y reuniones científicas
Título:
REGIONAL PALEOECOLOGY OF NEAR-FIELD MARINE FAUNAS DURING THE LATE PALEOZOIC ICE AGE, WESTERN ARGENTINA
Autor/es:
DINEEN, ASHLEY; FRAISER, MARGARET; TABOADA, ARTURO CÉSAR; PAGANI MARÍA A; ISBELL, JOHN
Lugar:
Denver
Reunión:
Encuentro; 2010 GSA Denver Annual Meeting; 2010
Institución organizadora:
Geological Society of America
Resumen:
The late Paleozoic Ice Age (LPIA) has long been known as an important
climatic event in Earths history. The end of the LPIA is the only example in
Earths history where a vegetated and biologically complex Earth transitioned
from a bipolar icehouse to a greenhouse state. Recent studies show that LPIA
climate changes broadly affected marine invertebrate faunas: glaciations
decreased origination and extinction, and long-term, gradual global warming
during the final deglaciation altered paleocommunity composition. Regional
far-field studies demonstrate that LPIA shallow tropical paleocommunities were
stable or weakly distinguishable, and comprised of similar sets of eurytopic
taxa.
Regional effects of LPIA glaciation and glacial retreat on high
paleolatitude (near-field) marine biotas have received very little attention.
We hypothesized that glacial to post-glacial fluctuations in near-field
settings were not conducive for community stability. It was predicted that near
glacial margins, faunas would exhibit characteristics indicative of low oxygen
and high sedimentation, including low diversity, small body size, and
opportunistic behavior.
The southwestern margin of Gondwana (present-day Argentina) has been
shown to have a complex history of interacting tectonism, climate, and
sea-level changes. Glacial and post-glacial faunal assemblages were examined in
the Paganzo, Río Blanco, and Tepuel-Genoa basins of northwestern and
southwestern Argentina. These were compared in order to gain environmental
perspectives on the effects of deglaciation on biota.
Diversity and abundance data from northwestern Argentina reflects that
ice-proximal environments proved physiologically stressful to organisms;
however, opportunistic assemblages successfully exploited ice-distal settings.
Following glaciation, the fauna of northwestern Argentina diversified and
became increasingly ecologically complex during two marine transgressions. In
comparison, ice-distal faunal assemblages in southwestern Argentina were
compositionally different than those in northwestern Argentina, yet maintained
high diversity. It is interpreted that paleocommunity establishment and
diversification in western Argentina during the LPIA was mostly dependent upon
localized environmental conditions.