Historia paleoambiental del Pleistoceno tardío-Holoceno del sitio arqueológico Cueva Tixi (Sierras de Tandilia, Argentina): un enfoque multiproxy.

ZUCOL, ALEJANDRO; HASSAN, GABRIELA S.; MARTÍNEZ, GUSTAVO A.; MAZZANTI, DIANA; COLOBIG, MARÍA DE LOS MILAGROS; PASSEGGI, ESTEBAN; QUINTANA, CARLOS

Necochea

Simposio; 9 Simposio Internacional El Hombre Temprano en América. La gente y sus Lugares.; 2018

Municipalidad de Necochea, CONICET, Dirección de Antropología Física-INAH

The paleontological and paleoenvironmental evidences provided byTandilia archaeological sites, allowed to identify several climatic andenvironmental changes occurred since the Late Pleistocene to the earlyHolocene, associated to floral and faunalremains.In the presentcontribution, the results of silica microremains (with special emphasis onphytoliths and diatoms) and micromammals bones remains predated byraptors from Cueva Tixi site are presented, in order to establish thepaleoenvironmental history of their sedimentary sequences, and to link itwith the different occupational stages of the site.Cueva Tixi sitesedimentary sequence covers from the late Pleistocene-late Holocene,distributed in six allostratigraphic units, and four archaeological levels.In Cueva Tixi sedimentological sequence 67,805 microvertebrateelements were recorded, of which 2675 correspond to micromammalspredated by Tyto alba in the Pleistocene-Holocene transition unit. Themicromammals of this level indicate the presence of environmental mosaicssuch as flooded surfaces and bodies of water (Holochilusbrasiliensis,Scapteromys sp.), grasslands (Calomys sp., Akodonazarae, Necromys sp., andMonodelphis sp. Indet.), shrubs (Reithrodonauritus and Thylamys sp.) and highsandy soils (Ctenomystalarum). Some associations, such as Lestodelphyshallitogether with Scapteromys and Monodelphis, are apparently environmentallyincongruous. This diversity is compatible with the environmentalheterogeneity and the landscape fragmentation of La Vigilancia hill.A total of 35 diatom taxa were identified in the sedimentary sequence(from which only 13 reached frequencies >2% in at least one sample), thatallowed to establish three significant diatom zones: the basal one thatcomprised the Pleistocene-Holocene transition, dominated by aerophilicdiatoms such Denticulaelegans and Nitzschiahantzschiana that indicate low water availability in the cave environment. While in the middle zone(towards the middle Holocene), Orthoseiradendroteres, N. hantzschiana andDiadesmisgallica dominated the assemblages, with elements evidencing ahigher water availability.Phytolith assemblage?s relationshipallowed to establish a basal zonecharacterized by the low panicoidphytolith abundance complemented bythe high presence of the pooid ones; while the sample towards the middleHoloceneshoweda greater abundance of megathermal indicators.The results obtained in the lower sedimentary levels of Cueva Tixiindicate cold and arid conditions prevailing in the region during the UpperPleistocene and Early Holocene, which evolved towards a regime of higherprecipitation and increased temperatures towards ca 10.000 years BP,evidencing warm and humid conditions for the Middle Holocene