Climatic change and human occupation in the preandean region of NW Argentina during the Upper Holocene

SAYAGO J.M.; SAMPIETRO M.M.; CARIA M.; COLLANTES M.M.

Malargüe Argentina

Simposio; Reconstructing Past Regional Climate Variations in South America over the late Holocene: A new PAGES Initiative; 2006

  Authors as O’Brien et al (1995), Van Geel & Renseen (1998), Sayago et al. (2005) postulated the existence of cool and/or wet period between 3,5 to 1,5 ky in different regions of the world that in the northwestern argentina would have coincide with the expanction of the main agrarian cultures. During the called Formative Period in the intermontaneous valley of Trancas (Yungas forest environment) Caria and Sayago (2005) established a Candelaria occupation dated in 3400 AP, which. ceramic remains in a well developed paleosols suggest wet and possible warm climate. Toward the west, in the Tafí Valley under a drier climate, several authors detected occupations from the Tafí culture between 2500 AP to 1200AP. The intensive agrarian activity in addition to polinic and palaeoedaphic evidences suggest wetter conditions than present, with a progressive tendency to dryness (Sampietro et al., 2003). The presence of extensive Formative terrace system in the Santa María Valley confirm the larger water availability during the Formative if compared with present day conditions. Strecker (1987) dated in 2190 AP fluvial back swamp sediment with a progressive transition to aridic conditions. Finally, in Antofagasta de la Sierra (Catamarca province), Tchilinguirian and Olivera, (2003) described in a cropping terrace, fluvial sediments dated in 3000 AP. In conclusion, during the 3,5 to 1,5 ky wet conditions influenced the spanction of the Formative cultures between the western Chaco and the dry Andes. The reinforcement of the Southern Atlantic High in addition to ITCZ would have influence the presence of wet and possible warmer environmental conditions between the 25º to 28º s. lat. A possible northward displacement of the Southern Paciphic Polar Front would have influence the meridional Puna Altiplain during that period.