Clim. Past Discuss., 9, 6125-6160, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper is under review for the journal Climate of the Past (CP).
Late Glacial-Holocene climatic transition record at the Argentinian Andean piedmont between 33–34° S
A. E. Mehl and M. A. Zárate
Instituto de Ciencias de la Tierra y Ambientales de La Pampa (INCITAP, CONICET), Universidad Nacional de La Pampa, Uruguay 151, Santa Rosa, La Pampa, Argentina

Abstract. The Arroyo La Estacada (~33°28' S, 69°02' W), eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant late Pleistocene–early Holocene (LP–EH) alluvial sequence including several paleosols. The arroyo sedimentary record exhibits a paleosol developed affecting the topmost part of likely Lateglacial aeolian deposits aggraded into a floodplain environment by the end of the late Pleistocene. The paleosol shows variable grade of development in the outcrops along the arroyo probably in relation to fluvial valley paleotopography. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, alluvial aggradation renewed and a higher frequency of flooding events could have affected the arroyo's floodplain environment.

A period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP–EH transition in response to a climatic amelioration in the Andes cordillera piedmont after the Late Glacial arid conditions. The renewal of early Holocene alluvial aggradation was probably influenced by the South American Monsoon and resulted in a change in the sedimentary dynamics of the arroyo.

The analyzed Late Glacial-Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP–EH climatic transition at the extra Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other sedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

Citation: Mehl, A. E. and Zárate, M. A.: Late Glacial-Holocene climatic transition record at the Argentinian Andean piedmont between 33–34° S, Clim. Past Discuss., 9, 6125-6160, doi:10.5194/cpd-9-6125-2013, 2013.
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