CECOAL   02625
CENTRO DE ECOLOGIA APLICADA DEL LITORAL
Unidad Ejecutora - UE
artículos
Título:
Holocene paleoagrostological impressions from the Eastern Chaco Region (Argentina)
Autor/es:
CONTRERAS, SILVINA A. ; LUTZ, ALICIA I.; ZUCOL, ALEJANDRO F.
Revista:
REVIEW OF PALAEOBOTANY AND PALYNOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2015 vol. 223 p. 37 - 49
ISSN:
0034-6667
Resumen:
The Chaco region is a sedimentary basin limited by the Andes and the Brazilian craton. This South Americansubtropical plain is defined as large alluvial fan sediments of the main rivers that were repeatedly depositedduring the late Quaternary under diverse climatic conditions. The Eastern Chaco is characterized bysemideciduous forests intermingled with extensive palm-savannas, with gallery forests being the commonvegetation along the banks of the main rivers and their western tributaries. These vegetation patterns of theChaco have been proposed to be the result of the Pleistocene?Holocene alluvial dynamics of the plain as wellas of the intensive migration of fluvial belts of the main rivers.Although no data are available on the paleoflora of the Chaco plain, plant fossil impressions are found in the banksof the low Bermejo River, which flows along the Eastern Chaco phytogeographic region. Here, we analyzepaleoagrostological impressions recovered from two fossiliferous localities in order to provide insights intothe environmental history of the Chaco region. Sixty complete Poaceae spikelet impressions were studiedmorphologically and compared with extant Chaco grass species. For each fossil spikelet, 11 morphologicalcharacters were described and statistically analyzed. All spikelets were found to belong to the Panicoideaesubfamily, and some have consistent morphological features with this subfamily; hence, we assign them to theextant genera Cenchrus, Echinochloa, Hymenachne, and Paspalum. These impressions are the first floral remainsfound in the Eastern Chaco and collectively suggest that environmental and climatic conditions from thesesediments corresponded to a subtropical humid climate and that vegetation was similar to the extant EasternChaco flora.