Historia ambiental de la Laguna Seca, Tartagal Salta, Noroeste Argentino

Abstract

First results from an interdisciplinary research on the history of landscape in the mountain range of Tartagal, Province of Salta (NW Argentina) for the 1959/2012 period are given. Geochemical, mineralogical and palynological studies with high temporal resolution have been performed in sediments of a core from Laguna Seca (22°21'1.81"S, 63°52'10.90"W). Dentations by 210 Pb show that the sedimentary record comprises 53 years. Sediments are composed of reddish massive clays and silts, with interbedded clays rich in organic matter and fibrous plants macro remains in the base of the core. Presence of quartz, illite and clinochlorite is prominent; most relevant geochemical components are Al, Si and K. Redundancy analysis indicates that most of chemical elements are associated to terrigenous minerals (quartz, albite and illite). Pollen types found belong to the Yungas forest, like Alnus acuminata, Anadenanthera colubrina, Celtis sp. and Schinus sp. Geochemical, mineralogical and palynological results are consistent with the annual precipitation in Tartagal during last decades, and reflect some correlation with phenomena of mass movement as well as landslides occurred in the mountain range of Tartagal and its oriental piedmont. The multiproxies data integration has generated the basis for reconstructing changes in vegetation, climate and history of anthropogenic disturbance during the Holocene in Subandine Sierra the Northwest Argentine.

Paleoenvironmental reconstruction of the semi-arid Chaco region of Argentina based on multiproxy lake records over the last six hundred years

“…In the Yala lakes (24°06′S, 65°28′W) and Laguna Seca (22°21′S, 63°52′W), which are located in the upper basin of Laguna Yema, an increase in humidity was recorded in 1960 CE as well as 1974 CE to the present (Lupo et al, 2006;Fierro et al, 2016). The Vilama-Coruto records also show a period with variable water availability (Morales et al, 2015b), but the humidity/aridity states are inverse with respect to Laguna Yema records, especially from 1945 to 2008, with a notable decrease in humidity conditions over the years.…”

“…Bennion et al, 2005;Bigler et al, 2009;Chen et al, 2009). Environmental changes that provoked modifications of drainage basin dynamics are precisely recorded in lake sediments (Fierro et al, 2016;Giralt and Julià, 2003). These modifications include disturbances in the river flow that feed the lake and variations in the amount of sediments and transport processes.…”

“…aquatic biota) (Cohen, 2003). Fierro et al (2016) and Giralt et al (2008) identified sediment transport process using redundancy analysis (RDA) with mineralogical and geochemical samples, as well as Principal Component Analysis (PCA) with high resolution geochemical composition data. Additionally, the analyses of the palynological composition of the stratigraphic column of lacustrine sediments allow for a multidisciplinary approach to the series of environmental changes and help clarify situations in paleoenvironmental analysis.…”

“…Examples include the presence of pollen types that indicate humidity variations, i.e. : Juncaginaceae, Cyperaceae, aquatic plants, fungi and ferns (Argollo and Murguiart, 2000;Fierro et al, 2016;Lupo et al, 2006); anthropogenic influences related to cattle grazing, e.g. Amaranthaceae/Chenopodiaceae (Pereira, 2014); and consequences of fires, e.g.…”