INVESTIGADORES
PONCE juan federico
artículos
Título:
Relict sand wedges in southern Patagonia and their stratigraphic and paleo-environmental significance
Autor/es:
BOCKHEIM, J.; CORONATO, A.; RABASSA, J.; ERCOLANO, B.; PONCE, J. F.
Revista:
QUATERNARY SCIENCE REVIEWS
Editorial:
Elsevier Editorial
Referencias:
Lugar: Amsterdam; Año: 2009 vol. 28 p. 1188 - 1199
ISSN:
0277-3791
Resumen:
Abstract: Relict sand wedges are ubiquitous in southern Patagonia. At six sites
we conducted detailed investigations of stratigraphy, soils, and wedge frequency
and characteristics. Some sections contain four or more buried horizons of casts.
The cryogenic features are dominantly relict sand wedges with an average depth,
maximum apparent width, minimum apparent width, and H/W of 78, 39, 3.8, and 2.9,
respectively. The host materials are fine-textured (silt loam, silty clay loam,
clay loam) till and the infillings are aeolian sand. The soils are primarily
Calciargidic Argixerolls that bear a legacy of climate change. Whereas the sand
wedges formed during very cold (-4 to -8 ºC or colder) and dry (ca. <100 mm
precipitation/yr) glacial periods, petrocalcic horizons from calcium carbonate
contributed by dustfall formed during warmer (7ºC or warmer) and moister (>250
mm/yr) interglacial periods. The paleo-argillic (Bt) horizons reflect unusually
moist interglacial events where the mean annual precipitation may have been 400
mm/yr. Permafrost was approximately continuous in southern Patagonia during the
Illinoian glacial stage (ca. 200 ka), the early to mid-Pleistocene (ca. 800-500
ka), and on two occasions during the early Pleistocene (ca. 1.0-1.1 Ma).