Holocene paleoenvironments human occupation and animal resources at south Andea Puna

OLIVERA, DANIEL; TCHILINGUIRIAN, PABLO

Burgos

Congreso; XVII World UISPP Congress; 2014

Fundacion Atapuerca

The Southern Puna is a morphostructural region which belongs to the Adean Cordillera. It covers 2,000,000 km2, and extends from 24º to 27º S and 66.5º to 68º W. It is characterized by extreme aridity with dry conditions (120 mm/yr), and ten year cycless of extreme drought (<10 mm) interrupted by years of abundant rain (200-300 mm). In this kind of environment, risky and uncertain conditions have to be considered in order to analyze economic strategies of the human groups. The aim of this work is to study the paleoenvironmental evolution in the Southern Puna during the Late Pleistocene and early-middle Holocene, in particular the changes between aridity and humidity, and to link this evolution to human occupation and animal resources management. Aerial photos and satellite images were analyzed to identify glacial, periglacial and lacustrine landscape geoforms with the aim of reconstructing the paleography from the late Quaternary to a regional scale. Detailed field studies of the Holocene deposits were performed on outcrops exposed over three valleys (Las Pitas (26.015°S, 67.325°W, 3645 m), Miriguaca (25.998ºS, 67.388ºW, 3471 m) and Confluencia (26.056°S, 67.41179°O, 3360m), and by sediment cores taken from different parts of the Salar of Laguna Colorada (26.032°S, 67.451°O, 3420m). Lithofacies and depositional environments were determined on all recovered units, using visual core descriptions and standard sedimentological facies analytical techniques. Emphasis was placed on the identification of changes in the vertical and horizontal facies indicated by variations in grain size, sedimentary structures, biogenic, pedogenic components and the abundance of organic material. Radiocarbon (AMS) dates (30) were obtained from bulk organic matter or plant debris. Different stable isotopes (2H, 18O and 3H) were analyzed in Los Colorados River (26.031º S, 67,448 ºW, 3421 m) and Las Pitas River (26,028ºS, 67.343ºW, 3581 m) in order to determine the origin of the recharge, its altitude and age. The results of these multiproxy analysis has allowed the differentiation of five paleoenvironmental phases, some regional and some local, that developed between 15000 and 4500 yr BP. These phases would be associated to climatic changes due to the obedience of the regional paleohydrological variability of the lakes and desert water courses towards, mostly, the hydric balance originated by the rainfall and evapotranspiration. Finally, in order of these results we make some observations about the potential incidence that the different paleoenvironmental conditions could have had for the human groups that inhabited the Puna during early and mid Holocene and the beginnings of the late Holocene considering the available archaeological record.