scholarly journals Bioavailable Strontium, Human Paleogeography, and Migrations in the Southern Andes: A Machine Learning and GIS Approach

2021 ◽  
Vol 9 ◽  
Author(s):  
Ramiro Barberena ◽  
Marcelo Cardillo ◽  
Gustavo Lucero ◽  
Petrus J. le Roux ◽  
Augusto Tessone ◽  
...  
Keyword(s):  
South America ◽  
Material Culture ◽  
Human Remains ◽  
Human Migration ◽  
Home Ranges ◽  
Mountain Range ◽  
Southern Andes ◽  
Isotopic Signatures ◽  
The Andes ◽  
Biogeographical Region

The Andes are a unique geological and biogeographic feature of South America. From the perspective of human geography, this mountain range provides ready access to highly diverse altitudinally arranged ecosystems. The combination of a geologically and ecologically diverse landscape provides an exceptional context to explore the potential of strontium isotopes to track the movements of people and the conveyance of material culture. Here we develop an isotopic landscape of bioavailable strontium (87Sr/86Sr) that is applied to reconstruct human paleogeography across time in the southern Andes of Argentina and Chile (31°–34°S). These results come from a macro-regional sampling of rodents (N = 65) and plants (N = 26) from modern and archeological contexts. This “Southern Andean Strontium Transect” extends over 350 km across the Andes, encompassing the main geological provinces between the Pacific coast (Chile) and the eastern lowlands (Argentina). We follow a recently developed approach to isoscape construction based on Random Forest regression and GIS analysis. Our results suggest that bioavailable strontium is tightly linked with bedrock geology and offers a highly resolved proxy to track human paleogeography involving the levels of territories or daily mobility and anomalous events that disrupt home ranges, such as migration. The southern Andes provide an ideal geological setting to develop this approach, since the geological variation in rock age and composition produces distinctive isotopic signatures for each main biogeographical region. Finally, we apply this framework to a set of results from human remains from the Uspallata Valley in Mendoza (Argentina), to assess the incidence of migration in the key period of the consolidation of agropastoral economies between AD 800 and 1400. The application of the isoscape to the values from human remains confirms the persistence of human groups with relatively restricted territories encompassing Uspallata and the adjacent Precordillera between AD 800 and 1500. We also identify a pulse of human migration between AD 1280 and 1420, shortly preceding the Inka conquest. Looking forward, we expect to converge with ongoing efforts in South America to build a continental research framework to track the movement of people, animals, and artifacts across space and time.

Spatiotemporal characteristics and synchronization of extreme rainfall in South America with focus on the Andes Mountain range

2015 ◽  
Vol 46 (1-2) ◽  
pp. 601-617 ◽  
Author(s):  
Niklas Boers ◽  
Bodo Bookhagen ◽  
Norbert Marwan ◽  
Jürgen Kurths
Keyword(s):  
South America ◽  
Extreme Rainfall ◽  
Mountain Range ◽  
Spatiotemporal Characteristics ◽  
The Andes ◽  
Andes Mountain

scholarly journals Convective Initiation near the Andes in Subtropical South America

2016 ◽  
Vol 144 (6) ◽  
pp. 2351-2374 ◽  
Author(s):  
K. L. Rasmussen ◽  
R. A. Houze
Keyword(s):  
South America ◽  
Physical Factors ◽  
Mountain Range ◽  
Convective Initiation ◽  
Convective Systems ◽  
Topographic Features ◽  
The Andes ◽  
Mesoscale Convective ◽  
Lee Cyclogenesis ◽  
Satellite Radar

Abstract Satellite radar and radiometer data indicate that subtropical South America has some of the deepest and most extreme convective storms on Earth. This study uses the full 15-yr TRMM Precipitation Radar dataset in conjunction with high-resolution simulations from the Weather Research and Forecasting Model to better understand the physical factors that control the climatology of high-impact weather in subtropical South America. The occurrence of intense storms with an extreme horizontal dimension is generally associated with lee cyclogenesis and a strengthening South American low-level jet (SALLJ) in the La Plata basin. The orography of the Andes is critical, and model sensitivity calculations removing and/or reducing various topographic features indicate the orographic control on the initiation of convection and its upscale growth into mesoscale convective systems (MCSs). Reduced Andes experiments show more widespread convective initiation, weaker average storm intensity, and more rapid propagation of the MCS to the east (reminiscent of the MCS life cycle downstream of lower mountains such as the Rockies). With reduced Andes, lee cyclogenesis and SALLJ winds are weaker, while they are stronger in increased Andes runs. The presence of the Sierras de Córdoba (secondary mountain range east of the Andes in Argentina) focuses convective initiation and results in more intense storms in experiments with higher Andes. Average CAPE and CIN values for each terrain modification simulation show that reduced Andes runs had lower CIN and CAPE, while increased Andes runs had both stronger CAPE and CIN. From this research, a conceptual model for convective storm environments leading to convective initiation has been developed for subtropical South America.

scholarly journals Magnetotelluric study in the Los Lagos Region (Chile) to investigate volcano-tectonic processes in the Southern Andes

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Maria Jose Segovia ◽  
Daniel Diaz ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Phase Changes ◽  
Fault System ◽  
Electrical Anisotropy ◽  
Mountain Range ◽  
Southern Andes ◽  
Nazca Plate ◽  
First Results ◽  
Dimensional Parameters

AbstractTo analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data-processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1 s and two-dimensional for periods greater than 10 s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80–100 km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.

scholarly journals Future climate change will impact the size and location of breeding and wintering areas of migratory thrushes in South America

The Condor ◽  
2021 ◽  
Author(s):  
Natália Stefanini Da Silveira ◽  
Maurício Humberto Vancine ◽  
Alex E Jahn ◽  
Marco Aurélio Pizo ◽  
Thadeu Sobral-Souza
Keyword(s):  
Climate Change ◽  
South America ◽  
Migratory Birds ◽  
Global Climate ◽  
Future Climate ◽  
Future Climate Change ◽  
Ecological Niche Models ◽  
Global Climate Changes ◽  
The Andes ◽  
Wintering Areas

Abstract Bird migration patterns are changing worldwide due to current global climate changes. Addressing the effects of such changes on the migration of birds in South America is particularly challenging because the details about how birds migrate within the Neotropics are generally not well understood. Here, we aim to infer the potential effects of future climate change on breeding and wintering areas of birds that migrate within South America by estimating the size and elevations of their future breeding and wintering areas. We used occurrence data from species distribution databases (VertNet and GBIF), published studies, and eBird for 3 thrush species (Turdidae; Turdus nigriceps, T. subalaris, and T. flavipes) that breed and winter in different regions of South America and built ecological niche models using ensemble forecasting approaches to infer current and future potential distributions throughout the breeding and wintering periods of each species. Our findings point to future shifts in wintering and breeding areas, mainly through elevational and longitudinal changes. Future breeding areas for T. nigriceps, which migrates along the Andes Mountains, will be displaced to the west, while breeding displacements to the east are expected for the other 2 species. An overall loss in the size of future wintering areas was also supported for 2 of the species, especially for T. subalaris, but an increase is anticipated for T. flavipes. Our results suggest that future climate change in South America will require that species shift their breeding and wintering areas to higher elevations in addition to changes in their latitudes and longitude. Our findings are the first to show how future climate change may affect migratory birds in South America throughout the year and suggest that even closely related migratory birds in South America will be affected in different ways, depending on the regions where they breed and overwinter.

Singa Transitional: Rock-art Saywas Marking Boundaries of Identity and Socializing Landscape in Huánuco, Peru

2021 ◽  
Vol 31 (2) ◽  
pp. 247-263
Author(s):  
Jonathan J. Dubois
Keyword(s):  
Material Culture ◽  
Rock Art ◽  
Social Changes ◽  
Regional Survey ◽  
Intermediate Period ◽  
Social Trends ◽  
The North ◽  
The Andes ◽  
Early Horizon ◽  
Landscape Feature

This paper introduces a new art style, Singa Transitional, found painted onto a mountainside near the modern town of Singa in the north of Huánuco, Peru. This style was discovered during a recent regional survey of rock art in the Huánuco region that resulted in the documentation of paintings at more than 20 sites, the identification of their chronological contexts and an analysis of the resulting data for trends in changing social practices over nine millennia. I explore how the style emerged from both regional artistic trends in the medium and broader patterns evident in Andean material culture from multiple media at the time of its creation. I argue that the presence of Singa Transitional demonstrates that local peoples were engaged in broader social trends unfolding during the transition between the Early Horizon (800–200 bc) and the Early Intermediate Period (ad 0–800) in Peru. I propose that rock art placed in prominent places was considered saywa, a type of landscape feature that marked boundaries in and movement through landscapes. Singa Transitional saywas served to advertise the connection between local Andean people and their land and was a medium through which social changes were contested in the Andes.

scholarly journals Quaternary Glaciations in the Andes of North-Central Chile

1975 ◽  
Vol 14 (70) ◽  
pp. 155-170 ◽  
Author(s):  
Cesar N. Caviedes ◽  
Roland Paskoff
Keyword(s):  
Polar Front ◽  
Southern Andes ◽  
North Central ◽  
Central Chile ◽  
The Andes ◽  
Semi Arid ◽  
Quaternary Glaciations ◽  
Chilean Andes

The extension of the Quaternary glaciations has been studied in the semi-arid Andes of north-central Chile, where the glacial modelling is striking. In the Elqui valley (lat. 30°S.), two glacial advances were identified reaching down to 3 100 m (Laguna glaciation) and 2 500 m (Tapado glaciation). In the Aconcagua valley (lat. 33°S.), moraines from three major glacial advances were found, at 2 800 m (Portillo glaciation), 1 600 m (Guardia Vieja glaciation) and 1 300 m (Salto del Soldado glaciation).The Quaternary glaciations were linked with a decrease of temperature, but more significantly with a marked increase of precipitation probably related to an equatorward shift of 5–6 degrees of the austral polar front. The results obtained in the semi-arid Chilean Andes are correlated with those recently reported from other sectors of the southern Andes.

scholarly journals Ordovician cephalopods in the Andes, South America.

1987 ◽  
Vol 63 (9) ◽  
pp. 316-318 ◽  
Author(s):  
Teiichi KOBAYASHI
Keyword(s):  
South America ◽  
The Andes
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