THE SIGNATURE OF RIVER- AND WIND-BORNE MATERIALS EXPORTED FROM PATAGONIA TO THE SOUTHERN LATITUDES:

DIEGO M. GAIERO A;
,PEDRO J. DEPETRIS A,JEAN-LUC PROBST B,

EARTH AND PLANETARY SCIENCE LETTERS

Elsevier

Lugar: Amsterdam; Año: 2004 p. 357 - 376

0012-821X

Riverine and wind-borne materials transferred from Patagonia to the SW Atlantic exhibit a homogeneous REEs signature. They match well with the REEs composition of Recent tephra from the Hudson volcano and, hence this implies a dominance of material supplied by this source and others similar Andean volcanoes. Due to the trapping effect of proglacial and reservoir lakes, the larger Patagonian rivers deliver to the ocean a suspended load with a slightly modified Andean signature, that shows a REEs composition depleted on HREE. In this paper we redefine Patagonia as a source of sediments, which is in contrast with others sources located in southern South America. Quaternary sediments deposited in the northern and, to a lesser extent, in the southern Scotia Sea, and most of the dust in ice cores of east Antarctica, have REE compositions very similar to the loess from Buenos Aires Province and to Patagonian aeolian dust. However, we rule out Buenos Aires province as a Holocene major source of sediments. Similarly to Buenos Aires loess (a proximal facies), it is likely that the REE compositions of most sediment cores of the Scotia Sea and Antarctica reflect a distal transport of dust with an admixed composition from two main sources: a major contribution from Patagonia, and in a minor proportion from source areas containing sediments with a clear upper crustal signature (e.g., western Argentina) or from Bolivia’s Altiplano. Evidence indicates that only during the Last Glacial Maximum, Patagonian materials were the predominant sediment source to the southern latitudes.