Human occupation chronologies modeled by geomorphological factors: A case study from the Atlantic Coast Northern Patagonia (Argentina)

Radiocarbon chronologies obtained in a dynamic landscape such as the coastal one provide valuable information about the different stages of its use, but they also reflect inevitable biases, many of them linked to geomorphological factors. Then, the study of these factors and their changes over time becomes an indispensable task in which geoarchaeology plays a relevant role. In this work, the Atlantic coast of Norpatagonia (San Matías Gulf, Argentina) is presented as a study case. In this coast the erosion of coastal geoforms eliminated archaeological sites of the Middle Holocene and the unequal development of wind deposits affected its temporal representation at the whole region. Both phenomena are linked to coastal dynamics and relative changes in sea level. Other environmental factors were responsible for shortening the chronologies provided by the rockshelters of the region. In this way, the geomorphological dynamics expressed in different types of discontinuities produced biases that affect the chronologies obtained for the human occupation of this region.Fil: Favier Dubois, Cristian Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano. Universidad Nacional del Centro de la Provincia de Buenos Aires. Investigaciones Arqueológicas y Paleontológicas del Cuaternario Pampeano; Argentin

The Marine Isotopic Stage 3 (MIS 3) in Valleys of the Undulated Pampa, Buenos Aires Province, Argentina

A depositional unit called DU2 identified for the period MIS 3 (ca- 30,000-60,000 yr. B.P.) formed by only one sedimentary facies (F3) was found in the Luján and Salto-Arrecifes rivers basins. F3 is a fluvio?lacustrine unit that overlies in erosive unconformity over eolian sediments with ages of 56,400 ± 6,500 and 50,400 ± 10,200 years B.A. and is unconformably covered by another eolian vitroclastic sandy loess deposit, dated as 32,000 ±4,000 years (Infrared Stimulated Luminescence, IRSL) (Blasi, et al. 2010). It represents the recurrence of ephemeral fluvial streamlets and the development of temporary pools by subsequent damming of channels. It corresponds lithologically to sandy muddy gravel, gravelly muddy sand, gravelly mud, olive to pale olive feldspar and quartz sands, bearing extinct mollusks such as Heleobia ameghini and Diplodon lujanensis. Radiocarbon chronologies obtained on monospecific samples of Cyprideis salebrosa hartmanni and Heleobia ameghini yielded ages of 37,710 ± 840 years 14C B.P. and >40,000 years 14C B.P., respectively. Furthermore, the age obtained through the IRSL technique was of 44,000 ± 6,500 years. Based upon the analyzed bioproxies (malacological, phytoliths and diatomological content) F3 accumulated under variable climatic conditions, ranging from temperate to colder and from subhumid to drier. According to the exhaustive stratigraphic identification, it is proposed that in NE Buenos Aires Province, the so-called Undulated Pampa region, the sediments that were accumulated during MIS3 occur only in the central portion of the studied fluvial basins. This prompted two hypotheses related to the existence of a particular drainage pattern for the Late Pleistocene, different from the present one, and subsequent tectonic controls that allowed the identification of DU2 sediments only in some of the analyzed sections.Fil: Blasi, Adriana María. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Mineralogía y Petrología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Castiñeira Latorre, Carola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Mineralogía y Petrología; ArgentinaFil: Cusminsky, Gabriela Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Carignano, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentin

Landscapes and Geology of Patagonia: An Introduction to the Land of Reptiles

The purpose of this chapter is to summarize the geological-geomorphologicalregions of Patagonia with a general characterization of the maingeomorphological units. A review of studies on geology, stratigraphic, main geologiclandmarks, geological history, and geological resources will be brieflydescribed. This review was performed on the base of geological province concept,including a stratigraphic-morphostructural criteria and a description of majorendogenous and exogenous processes responsible for the formation of landscapeunits. In this chapter these geological-geomorphological regions include Chile andArgentina and were grouped as: (1) Coastal Cordillera and Central Valley (Chile),(2) Southern Andes Cordillera, (3) Mountain Sector of the Neuquén Embayment,(4) Northern Patagonian Tablelands, (5) The North Patagonian Broken Foreland andSomún Curá Massif, (6) Central Patagonian Tablelands, (7) Deseado Massif, (8)Southern Patagonian Tableland, and (9) Islas Malvinas Plateau.Fil: Bouza, Pablo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Bilmes, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentin