A new marine mammal assemblage from central Chile reveals the Pliocene survival of true seals in South America

Abstract. High-resolution reconstructions of climate variability that cover the past millennia are necessary to improve the understanding of natural and anthropogenic climate change across the globe. Although numerous records are available for the mid- and high-latitudes of the Northern Hemisphere, global assessments are still compromised by the scarcity of data from the Southern Hemisphere. This is particularly the case for the tropical and subtropical areas. In addition, high elevation sites in the South American Andes may provide insight into the vertical structure of climate change in the mid-troposphere. This study presents a 3000 yr long austral summer (November to February) temperature reconstruction derived from the 210Pb and 14C dated organic sediments of Laguna Chepical (32°16' S/70°30' W, 3050 m a.s.l.), a high-elevation glacial lake in the subtropical Andes of central Chile. Scanning reflectance spectroscopy in the visible light range provided the spectral index R570/R630, which reflects the clay mineral content in lake sediments. For the calibration period (AD 1901–2006), the R570/R630 data were regressed against monthly meteorological reanalysis data, showing that this proxy was strongly and significantly correlated with mean summer (NDJF) temperatures (R3yr = −0.63, padj = 0.01). This calibration model was used to make a quantitative temperature reconstruction back to 1000 BC. The reconstruction (with a model error RMSEPboot of 0.33 °C) shows that the warmest decades of the past 3000 yr occurred during the calibration period. The 19th century (end of the Little Ice Age (LIA)) was cool. The prominent warmth reconstructed for the 18th century, which was also observed in other records from this area, seems systematic for subtropical and southern South America but remains difficult to explain. Except for this warm period, the LIA was generally characterized by cool summers. Back to AD 1400, the results from this study compare remarkably well to low altitude records from the Chilean Central Valley and Southern South America. However, the reconstruction from Laguna Chepical does not show a warm Medieval Climate Anomaly during the 12–13th century, which is consistent with records from tropical South America. The Chepical record also indicates substantial cooling prior to 800 BC. This coincides with well-known regional as well as global glacier advances which have been attributed to a grand solar minimum. This study thus provides insight into the climatic drivers and temperature patterns in a region for which currently very few data are available. It also shows that since ca AD 1400, long term temperature patterns were generally similar at low and high altitudes in central Chile.

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Studies on the moss flora of the Bío-Bío region of Chile

Bryophyte Diversity and Evolution ◽

10.11646/bde.28.1.11 ◽

2006 ◽

Vol 28 (1) ◽

pp. 63-77 ◽

Cited By ~ 1

Author(s):

Robert R. Ireland ◽

Gilda Bellolio ◽

Roberto Rodríguez ◽

Juan Larraín

Keyword(s):

South America ◽

New Taxa ◽

New Records ◽

Recent Literature ◽

Extensive Study ◽

Central Chile ◽

Number Of Species ◽

South Central ◽

Made In

An extensive study was made on the moss flora of the Bío-Bío Region (VIII Región) in south-central Chile in 2001-2003. Collections were made in all four provinces of the region: Arauco, Bío-Bío, Concepción and Ñuble. Approximately 265 localities in the region were explored with over 6,000 mosses collected in the four provinces. The mosses of this region had not previously been studied to any great extent and with part of the region’s environment being destroyed by the construction of several dams on one of the major rivers, the Bío-Bío, the study of this area seemed of utmost importance. Thus far, a total of 20 taxa were found which are new to Chile, making a total of 877 known for the country, with four new taxa known for South America. An additional 87 taxa are reported new only to the Bío-Bío Region. That number, together with some new records from the recent literature, increases the total for the Region from 190 to 300. It was determined from the 87 new taxa for the Bío-Bío Region that the majority (41) represent northern extensions of taxa, while a much smaller number (10) represent southern extensions. The remainder (36) fill in a gap in the distribution of the taxa between the northern and southern parts of the country. Many difficult species still remain to be identified and the number of species new to science, to Chile and to the Bío-Bío Region, is certain to increase when the remaining specimens are identified.

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Quest for the Origins and Implications for Social Rights of the Mapuche in the Southern Cone of South America

Latin American Antiquity ◽

10.7183/1045-6635.24.2.149 ◽

2013 ◽

Vol 24 (2) ◽

pp. 149-163 ◽

Cited By ~ 7

Author(s):

Tom D. Dillehay ◽

Francisco Rothhammer

Keyword(s):

South America ◽

Cultural Influences ◽

Southern Cone ◽

Social Rights ◽

Indigenous Status ◽

Central Chile ◽

High Profile ◽

South Central ◽

Indigenous Groups ◽

First Time

Debates over the cultural and biological origins of some indigenous groups in the Americas have fueled discussions about cultural identity, political justice, and resource rights. A historically high-profile case of rights and origins has involved the Araucanians or Mapuche of the southern cone of South America. This article examines, for the first time, the recent interdisciplinary archaeological and other anthropological evidence for the Mapuche of Chile and Argentina. It suggests that the ethnic and territorial origin of the Mapuche is in central and south-central Chile, although biological and cultural influences from north Chile and western Argentina also are present. It briefly discusses the implication of this study in relation to the indigenous status of the Mapuche in present-day Chile and Argentina.

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Darwin the geologist in southern South America

Earth Sciences History ◽

10.17704/1944-6178-35.2.303 ◽

2016 ◽

Vol 35 (2) ◽

pp. 303-345 ◽

Cited By ~ 2

Author(s):

Robert H. Dott ◽

Ian W. D. Dalziel

Keyword(s):

South America ◽

Charles Darwin ◽

Lateral Compression ◽

Central Chile ◽

Southern South America ◽

The Andes ◽

Andean Cordillera ◽

Marine Terraces ◽

Four Books ◽

Geological Map

Charles Darwin was a reputable geologist before he achieved biological fame. Most of his geological research was accomplished in southern South America during the voyage of H.M.S. Beagle (1831–1836). Afterward he published four books and several articles about geology and coral atolls and became active in the Geological Society of London. We have followed Darwin's footsteps during our own researches and have been very impressed with his keen observations and inferences. He made some mistakes, however, such as appealing to iceberg rafting to explain erratic boulders and to inundations of the sea to carve valleys. Darwin prepared an important hand-colored geological map of southern South America, which for unknown reasons he did not publish. The distributions of seven map units are shown. These were described in his books wherein he also documented multiple elevated marine terraces on both coasts of South America. While exploring the Andean Cordillera in central Chile and Argentina, he discovered two fossil forests. Darwin developed a tectonic theory involving vertical uplift of the entire continent, which was greatest in the Andes where magma leaked up from a hypothetical subterranean sea of magma to form volcanoes and earthquakes. The theory had little impact and was soon eclipsed by theories involving lateral compression of strata. His and other contemporary theories suffered from a lack of knowledge about the earth's interior. Finally with modern plate tectonic theory involving intense lateral compression across the Andean Cordillera we can explain satisfactorily the geology so carefully documented by Darwin.

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Geology of part of a long-lived dynamic plate margin: the coastal cordillera of north-central Chile, latitude 30°51′–31°S

Canadian Journal of Earth Sciences ◽

10.1139/e88-058 ◽

1988 ◽

Vol 25 (4) ◽

pp. 603-624 ◽

Cited By ~ 12

Author(s):

James J. Irwin ◽

Carlos García ◽

Francisco Hervé ◽

Maureen Brook

Keyword(s):

South America ◽

Tierra Del Fuego ◽

First Episode ◽

North Central ◽

Central Chile ◽

Igneous Complex ◽

Plate Margin ◽

Rock Formations ◽

Facies Metamorphism ◽

Basaltic Lavas

A complex composed of ultrabasic and basaltic lavas, chert, arkose, and conglomerate was assembled in the coast of north-central Chile (lat. 30°30′–31°S) prior to 200 Ma. The character of, and relationships between, the rock formations exposed here are consistent with an autochthonous evolution of this part of Chile in the last 200 Ma. Three major episodes of deformation and metamorphism have been observed in this area. The first episode (F1) produced a compositional layering (S1) and amphibolite-facies metamorphism coeval with the intrusion of an extensive igneous complex between 220 and 200 Ma. A second episode of deformation (F2) locally formed reverse faults and tight, recumbent folds in S1. Units in which F2 folds are well developed yield K–Ar and Rb–Sr ages between 163 and 140 Ma. At between 140 and 126 Ma, upright, open to tight folds (F3) formed with sharp hinges and axial planes that strike north and dip steeply east. Structures of similar age, style, and orientation have been reported as far south as Tierra del Fuego. The timing of the F3 deformation appears to correspond to the opening of the South Atlantic Ocean and accelerated westward motion of South America.

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Marine terraces of the last interglacial period along the Pacific coast of South America (1° N–40° S)

Earth System Science Data ◽

10.5194/essd-13-2487-2021 ◽

2021 ◽

Vol 13 (6) ◽

pp. 2487-2513

Author(s):

Roland Freisleben ◽

Julius Jara-Muñoz ◽

Daniel Melnick ◽

José Miguel Martínez ◽

Manfred R. Strecker

Keyword(s):

South America ◽

Sea Level ◽

Short Wavelength ◽

Tidal Range ◽

Uplift Rate ◽

Last Interglacial ◽

Central Chile ◽

Long Wavelength ◽

South Central ◽

Marine Terraces

Abstract. Tectonically active coasts are dynamic environments characterized by the presence of multiple marine terraces formed by the combined effects of wave erosion, tectonic uplift, and sea-level oscillations at glacial-cycle timescales. Well-preserved erosional terraces from the last interglacial sea-level highstand are ideal marker horizons for reconstructing past sea-level positions and calculating vertical displacement rates. We carried out an almost continuous mapping of the last interglacial marine terrace along ∼ 5000 km of the western coast of South America between 1∘ N and 40∘ S. We used quantitatively replicable approaches constrained by published terrace-age estimates to ultimately compare elevations and patterns of uplifted terraces with tectonic and climatic parameters in order to evaluate the controlling mechanisms for the formation and preservation of marine terraces and crustal deformation. Uncertainties were estimated on the basis of measurement errors and the distance from referencing points. Overall, our results indicate a median elevation of 30.1 m, which would imply a median uplift rate of 0.22 m kyr−1 averaged over the past ∼ 125 kyr. The patterns of terrace elevation and uplift rate display high-amplitude (∼ 100–200 m) and long-wavelength (∼ 102 km) structures at the Manta Peninsula (Ecuador), the San Juan de Marcona area (central Peru), and the Arauco Peninsula (south-central Chile). Medium-wavelength structures occur at the Mejillones Peninsula and Topocalma in Chile, while short-wavelength (< 10 km) features are for instance located near Los Vilos, Valparaíso, and Carranza, Chile. We interpret the long-wavelength deformation to be controlled by deep-seated processes at the plate interface such as the subduction of major bathymetric anomalies like the Nazca and Carnegie ridges. In contrast, short-wavelength deformation may be primarily controlled by sources in the upper plate such as crustal faulting, which, however, may also be associated with the subduction of topographically less pronounced bathymetric anomalies. Latitudinal differences in climate additionally control the formation and preservation of marine terraces. Based on our synopsis we propose that increasing wave height and tidal range result in enhanced erosion and morphologically well-defined marine terraces in south-central Chile. Our study emphasizes the importance of using systematic measurements and uniform, quantitative methodologies to characterize and correctly interpret marine terraces at regional scales, especially if they are used to unravel the tectonic and climatic forcing mechanisms of their formation. This database is an integral part of the World Atlas of Last Interglacial Shorelines (WALIS), published online at https://doi.org/10.5281/zenodo.4309748 (Freisleben et al., 2020).

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The Mediterranean Environment of Central Chile

The Physical Geography of South America ◽

10.1093/oso/9780195313413.003.0019 ◽

2007 ◽

Cited By ~ 2

Author(s):

Juan J. Armesto ◽

Mary T. K. Arroyo

Keyword(s):

South America ◽

Biological Diversity ◽

Narrow Band ◽

Mediterranean Environment ◽

Central Chile ◽

The Andes ◽

Selective Approach ◽

Physical Setting ◽

The Mediterranean ◽

Western Side

The Mediterranean-type environment of South America, broadly defined as the continental area characterized by winter rainfall and summer drought, is confined to a narrow band about 1,000 km long on the western side of the Andes in north-central Chile (Arroyo et al., 1995, 1999). Although much has been written about the climate, vegetation, and landscapes of this part of Chile, and comparisons have been drawn with California and other Mediterranean-type regions of the world (Parsons, 1976; Mooney, 1977; Rundel, 1981; Arroyo et al., 1995), a modern synthesis of information on the physical setting, regional biota, and historical development of ecosystems in central Chile has not been attempted. This chapter is intended to provide such an integrated picture, emphasizing those aspects most peculiar to the region. Since the earlier floristic work on the Chilean matorral (e.g. Mooney, 1977), the name given to the vegetation of central Chile, there is now a much greater appreciation of the geographic isolation and high levels of biological diversity and endemism in this region of South America (Arroyo and Cavieres, 1997; Villagrán, 1995; Arroyo et al., 1995, 1999). Because of the great richness and singularity of its terrestrial flora, this area of the continent is considered to be one of the world’s 25 hotspots in which to conserve global biodiversity (Arroyo et al., 1999; Myers et al., 2000). An analysis of the main features of the Mediterranean environment in South America should therefore address the causes of such high floristic richness, the nature of current threats to biodiversity, and the prospects for its conservation in the long-term. A discussion of conservation concerns closes the present chapter (but see also: Arroyo and Cavieres, 1997; and Arroyo et al., 1999). In view of the vast literature on the biota and physical setting of central Chile, this chapter adopts a selective approach, from a biogeographic perspective, of what we consider to be the most remarkable historical, physical, and ecological features of this environment, which in turn may explain its extraordinary richness in plants and animals. Mediterranean-type ecosystems occupy a narrow band along the western margin of South America, from 30 to 36°S in central Chile.

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Regional drought in the southern of South America: physical aspects

Revista Brasileira de Meteorologia ◽

10.1590/s0102-77862010000100008 ◽

2010 ◽

Vol 25 (1) ◽

pp. 88-102 ◽

Cited By ~ 1

Author(s):

Juan Leonidas Minetti ◽

Walter Mario Vargas ◽

Arnobio German Poblete ◽

Maria Elvira Bobba

Keyword(s):

South America ◽

Atmospheric Pressure ◽

Regional Scale ◽

Atmospheric Temperature ◽

Sea Surface ◽

Brazilian Coast ◽

Subtropical Anticyclone ◽

Central Chile ◽

The Pacific ◽

Regional Drought

From the indices of monthly and annual climatic drought in six regions in southern South America and their associations with seventeen predictors, the probable physical causes of droughts are analyzed. These indices are used in operational climate monitoring and describe the atmospheric temperature and sea surface temperature (SST) near South America. Subtropical anticyclone activity over both coasts of South America is one of the main predictors, together with its interaction with the continental depression and SST at the coast of Brazil. The highest predictability concentrates in November-December-May and the lowest in March, June and August. In the sub regional scale, the main predictors respond to atmospheric pressure anomalies in the Atlantic Ocean for Argentinean Northwest (NOA), SST in the Brazilian coast for Argentinean Northeast (NEA), anticyclonic conditions over the Pacific and Atlantic for the Central West (CO), the latter and their interaction with the continental depression for Humid Pampa (PH), anticyclonic activity over the Pacific for the Patagonia (PAT) and trans cordillera circulation for Central Chile and Comahue (CHI).

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First evidences of an underwater Final Pleistocene terrestrial extinct faunal bone assemblage from Central Chile (South America): taxonomic and taphonomic analyses

Quaternary International ◽

10.1016/j.quaint.2012.07.361 ◽

2012 ◽

Vol 279-280 ◽

pp. 82

Author(s):

Isabel Cartajena

Keyword(s):

South America ◽

Central Chile

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Recent Changes in the Low-Level Jet along the Subtropical West Coast of South America

Atmosphere ◽

10.3390/atmos12040465 ◽

2021 ◽

Vol 12 (4) ◽

pp. 465

Author(s):

Catalina Aguirre ◽

Valentina Flores-Aqueveque ◽

Pablo Vilches ◽

Alicia Vásquez ◽

José A. Rutllant ◽

...

Keyword(s):

South America ◽

West Coast ◽

Southern Boundary ◽

Central Chile ◽

Low Level ◽

Long Term Trends ◽

Low Level Jet ◽

Wind Events ◽

Ocean Environment ◽

June July

Surface winds along the subtropical west coast of South America are characterized by the quasi-weekly occurrences of low-level jet events. These short lived but intense wind events impact the coastal ocean environment. Hence, identifying long-term trends in the coastal low-level jet (CLLJ) is essential for understanding changes in marine ecosystems. Here we use ERA5 reanalysis (1979–2019) and an objective algorithm to track anticyclones to investigate recent changes in CLLJ events off central Chile (25–43 °S). Results present evidence that the number of days with intense wind (≥10 ms−1), and the number and duration of CLLJ events have significantly changed off central Chile in recent decades. There is an increase in the number of CLLJ events in the whole study area during winter (June-July-August; JJA), while during summer (December–January–February; DJF) a decrease is observed at lower latitudes (29–34 °S), and an increase is found at the southern boundary of the Humboldt system. We suggest that changes in the central pressures and frequency of extratropical, migratory anticyclones that reach the coast of South America, which force CLLJs, have played an important role in the recent CLLJ changes observed in this region.

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