First record of fossil wood and phytolith assemblages of the late Pleistocene in El Palmar National Park (Argentina)

ZUCOL, A.F., BREA. M AND A. SCOPEL

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

Elsevier

Lugar: Amsterdam; Año: 2005 vol. 20 p. 33 - 43

0895-9811

Abstract Two paleoxylologic assemblages and two phytolith assemblages were recovered from Late Pleistocene sediments of El Palmar Formation. These deposits are found in outcrops along the western margin of the Uruguay River. The spectra of taxa obtained in both sets by different methods is complementary. The fossil remains are characterized in terms of floristic composition and paleoclimate. Seven families are recognized: Podostemaceae, Myrtaceae, Anacardiaceae, Mimosoideae, Arecaceae, Poaceace, and Cyperaceae. Sponge siliceous spicules also have been found in these assemblages. The state of preservation of the phytoliths and their weathering degree is analyzed. These studies can be used as a potential paleoecological tool for alluvial sediments. The comparison of fossil assemblages with modern analogs clarifies the paleoecological requirements and composition of two paleocommunities, one dominated by woody forests and the other by palms. The climatic conditions inferred from the reconstructed vegetation and sedimentary deposits indicate a temperate-warm, humid climate. The results constitute the first evidence of the floral diversity of the vegetation in El Palmar National Park during the Late Pleistocene. q 2005 Elsevier Ltd. All rights reserved.2005 Elsevier Ltd. All rights reserved. Keywords: Argentina; Fossil wood assemblages; Late Pleistocene; Paleovegetation; Phytolith assemblagesArgentina; Fossil wood assemblages; Late Pleistocene; Paleovegetation; Phytolith assemblages