INVESTIGADORES
GAIERO Diego Marcelo
artículos
Título:
A uniform isotopic and chemical signature of dust exported
Autor/es:
DIEGO M. GAIERO, FREDERIC BRUNET, JEAN-LUC PROBST, PEDRO J. DEPETRIS
Revista:
CHEMICAL GEOLOGY
Editorial:
Elsevier
Referencias:
Año: 2007 p. 107 - 120
ISSN:
0009-2541
Resumen:
Patagonia is considered to be the most important source of dust from South America that is deposited in surrounding areas, and
we present here a systematic Sr and Nd isotopic study of sediment currently being exported. Eolian and suspended riverine
sediments from Patagonia have a homogeneous chemical and isotopic composition that results from the mixing of by-products
from explosive Andean volcanism, derived from the extensive Jurassic silicic Province of Chon Aike and pyroclastic materials
from the basic to intermediate southern Andean Quaternary arc, which are easily denudated and dispersed. The main Andean uplift
and the glaciations that began in the Late Tertiary account for the extensive distribution of these sediments in the extra-Andean
region. The present geochemical signature of Patagonian sediments was produced during the Pleistocene, along with the onset of
the southern Andean explosive arc volcanism. Previously published compositions of sediments from other southern South
American source regions, assumed to be representative of Patagonia, are distinct from our data. Considering the alleged importance
of Patagonia as a dust source for different depositional environments in southern latitudes, it is surprising to verify that the chemical
and isotopic signatures of Patagonian-sourced sediments are different from those of sediments from the Southern Ocean, the
Pampean Region or the Antarctic ice. Sediments from these areas have a crustal-like geochemical signature reflecting a mixed
origin with sediment from other southern South American sources, whereas Patagonian sediments likely represent the basic to
intermediate end-member composition