Paleomagnetic Results from Archaeological Sites in Argentinean Patagonia: Evidence for the Holocene Geomagnetic Excursions in Southern South America and Its Chronostratigraphic Implications

Abstract

Detailed palaeomagnetic research performed in archaeological and paleontological sites in southern South America yielded a number of highly fluctuating paleosecular variation records with geomagnetic field excursion(s) during the Holocene. To assess this topic a variety of sections of recent sediments were sampled. In the case presented here they belong from diverse continental sedimentary sequences formed in coastal marine and cave's environments. Paleomagnetic samplings were performed in several deposits in San Blas Bay and Pali Aike areas, respectively located in the northern and southern parts of Argentinean Patagonia region. To collect samples, cylindrical plastic containers 2.5 cm long and 2 cm diameter were carefully pushed into the sections, overlying each other by about 50 percent. Their strike and dip were measured using a Brunton compass and inclinometer; they were consolidated with sodium silicate after removal and numbered from top to bottom. All samples were subjected to progressive AF demagnetization in steps of 3, 6, 9, 12, 15, 20, 25, 30, 40 and 60 mT in a 3-axis static degausser attached to a 2 G cryogenic magnetometer. Additional steps from 80 to 120 mT were used in some samples. Characteristic remnant magnetization was calculated using principal-components analysis, with the best-fitting line going to the origin in the Zijderveld diagrams. In general, maximum angular deviations were generally within low values. Some samples had univectorial behavior, while some showed two or three components. Most of the sections show normal and intermediate polarity directions far from the present GF, while reversed polarities were recorded at San Blas 2, La Serranita 1 and Punta Rubia 2 sites in San How to cite this paper: Nami, H. G.

Paleoamerican Occupation, Stone Tools from the Cueva del Medio, and Considerations for the Late Pleistocene Archaeology in Southern South America

“…It is defined as a deviation of the virtual geomagnetic pole by more than 40-45 • from the geographic pole ( Figure 18) and as causing a major deviation in the GMF's behavior during a brief time span [130,131]. Additional evidence has been observed at the CM, and at other sites in Patagonia and southern South America [25,[132][133][134][135], as well in other parts of the world see [136,137]. As previously discussed [138], paleomagnetic records with anomalous directions may be due to several reasons, but they may also reflect true GMF excursions.…”

A Glimpse into Advances in Archaeological Research in North-Central Uruguay

“…an archaeological locality that yielded a FP (Figure 17 ing the terminal Pleistocene and early, middle and late Holocene (Nami, 2012(Nami, , 2015b(Nami, , 2019bNami et al, 2016. Particularly in this region, the existence of this anomaly has been suggested by a wide pulse in declination during the middle Holocene in previous studies undertaken at the Uruguay River shore in southeastern Corrientes Province on the Argentine-Uruguayan border (Nami, 2011a: Figure 7).…”

“…In addition to the expected normal directions, some of them show significant directional changes in declination and inclination with intermediate and reverse VGP positions during the terminal Pleistocene and Holocene (e.g. Nami, 1995aNami, , 1999Nami, , 2011aNami, , 2019b.…”

Cronología De Las Ocupaciones Humanas en El Campo Volcánico Pali-Aike: Aportes Desde El Interfluvio Gallegos-Chico Y Valle Medio Del Río Chico (Santa Cruz, Argentina)

“…La superficie muestreada cubrió 181.000 m 2 (L'Heureux et al 2020). Los trabajos permitieron detectar nuevos sitios en las estancias Markatch-Aike y Pali-Aike que se suman a los ya estudiados por Gómez Otero y Fontanella (1981) y Nami y colaboradores (e.g Borromei & Nami, 2000;Hernández Llosas et al 1999;Nami, 1994Nami, , 1995Nami, , 1997aNami, , 1997bNami, , 1999Nami, , 2009Nami, , 2019Nami & Frink, 1999;Nami et al 2017).…”

“…Es, precisamente, durante el Holoceno tardío que se registra la mayoría de los sitios en el interfluvio (Manantial 1, Alero Clark 1, Laguna Ea. Tres Lagunas, Alero Potrok-Aike 1, Alero Juni-Aike 1, Exterior de Cueva 1 Potrok-Aike, Bella Vista 1 (Banegas et al 2014, Gómez Otero, 1986-1987, 1993; Tabla 1), como también en el valle medio del río Chico (Markatch-Aike 1, Markatch-Aike 2, Co. Cóndor Cueva 1, Cueva Montecarlo, Alero del Valle y Cueva Don Ariel (Nami, 1995(Nami, , 2019Nami & Frink, 1999;Nami et al 2017; Tabla 1 y Fig. 7c).…”