Genetic implications of a retransported loess profile near Córdoba,Argentina |
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| Authors: | GL Argüello R Dohrmann JA Sanabria E Zahn |
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| Institution: | 1. Faculty of Physics, Paleomagnetic Laboratory, University of Bucharest, N. Balcescu 1, 010041 Bucharest, Romania;2. Laboratory of Magnetism and Superconductivity, National Institute of Materials Physics, Atomistilor 105 bis, PO Box MG7, 077125 Bucharest-Magurele, Romania;1. Department of Earth Sciences, University of Minnesota, Minneapolis, MN, United States;2. Institute for Rock Magnetism, University of Minnesota, Minneapolis, MN, United States |
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| Abstract: | This paper deals with a loess profile located southeast of Córdoba (64° 05′ 30 W to 31°30′ S) that was dated in Beijing University using the OSL method according to Simple Aliquot Regeneration Protocol. This study provides some inferences regarding climatic and environmental features, such as transport agents and probable sources of the materials.The profile, located inside Llanura Pampeana, is approximately 6.80 m in depth and comprises ages between 22.4 ± 3.2 and 9.9 ± 0.3 ka. Throughout the profile, and for all grain sizes, major minerals are quartz and feldspar, with micas, and opaques as subordinates. Illite and chlorite appear as traces, though the last one was not confirmed in the finest fraction analysis. Calcite is abundant in the uppermost sample and decreases downwards. In the base of the profile, and in the clay fraction, XRD showed illite, swellable clay minerals (smectite + mixed layers) and kaolinite traces. It was concluded that the profile would have been derived from the accumulation of sediments, along several events very similar in transport conditions, even though there are some indications that about 21 ka BP, water availability was slightly smaller than for the rest of the profile. This change was also established in some other places, allowing some regional correlations. According to the analyzed data, about 19 ka BP, water availability again increased. |
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