scholarly journals Hydroclimate variability in the low-elevation Atacama Desert over the last 2500 years

2011 ◽  
Vol 7 (5) ◽  
pp. 3165-3202
Author(s):  
E. M. Gayo ◽  
C. Latorre ◽  
C. M. Santoro ◽  
A. Maldonado ◽  
R. De Pol-Holz
Keyword(s):  
Hydrological Cycle ◽  
Atacama Desert ◽  
Plant Macrofossils ◽  
Central Andes ◽  
Tropical Pacific ◽  
Riparian Ecosystems ◽  
Independent Evidence ◽  
Radiocarbon Dates ◽  
Climate Fluctuations ◽  
The Past

Abstract. Paleoclimate reconstructions reveal that Earth system has experienced sub-millennial scale climate changes over the past two millennia in response to internal/external forcing. Although sub-millennial hydroclimate fluctuations have been detected in the central Andes during this interval, the timing, magnitude, extent and direction of change of these events remain poorly defined. Here, we present a reconstruction of hydroclimate variations on the Pacific slope of the central Andes based on exceptionally well-preserved plant macrofossils and associated archaeological remains from a hyperarid drainage (Quebrada Maní, ~21° S, 1000 m a.s.l.) in the Atacama Desert. During the late Holocene, riparian ecosystems and farming social groups flourished in the hyperarid Atacama core as surface water availability increased throughout this presently sterile landscape. Twenty-six radiocarbon dates indicate that these events occurred between 1050–680, 1615–1350 and 2500–2040 cal yr BP. Regional comparisons with rodent middens and other records suggest that these events were synchronous with pluvial stages detected at higher-elevations in the central Andes over the last 2500 years. These hydroclimate changes also coincide with periods of pronounced SST gradients in the Tropical Pacific (La Niña-like mode), conditions that are conducive to significantly increased rainfall in the central Andean highlands and flood events in the low-elevation watersheds at inter-annual timescales. Our findings indicate that the positive anomalies in the hyperarid Atacama over the past 2500 years represent a regional response of the central Andean climate system to changes in the global hydrological cycle at centennial timescales. Furthermore, our results provide support for the role of tropical Pacific sea surface temperature gradient changes as the primary mechanism responsible for climate fluctuations in the central Andes. Finally, our results constitute independent evidence for comprehending the major trends in cultural evolution of prehistoric peoples that inhabited the region.

scholarly journals Hydroclimate variability in the low-elevation Atacama Desert over the last 2500 yr

2012 ◽  
Vol 8 (1) ◽  
pp. 287-306 ◽  
Author(s):  
E. M. Gayo ◽  
C. Latorre ◽  
C. M. Santoro ◽  
A. Maldonado ◽  
R. De Pol-Holz
Keyword(s):  
Hydrological Cycle ◽  
Atacama Desert ◽  
Plant Macrofossils ◽  
Central Andes ◽  
Tropical Pacific ◽  
Riparian Ecosystems ◽  
Independent Evidence ◽  
Radiocarbon Dates ◽  
Climate Fluctuations ◽  
The Past

Abstract. Paleoclimate reconstructions reveal that Earth system has experienced sub-millennial scale climate changes over the past two millennia in response to internal/external forcing. Although sub-millennial hydroclimate fluctuations have been detected in the central Andes during this interval, the timing, magnitude, extent and direction of change of these events remain poorly defined. Here, we present a reconstruction of hydroclimate variations on the Pacific slope of the central Andes based on exceptionally well-preserved plant macrofossils and associated archaeological remains from a hyperarid drainage (Quebrada Maní, ∼21° S, 1000 m a.s.l.) in the Atacama Desert. During the late Holocene, riparian ecosystems and farming social groups flourished in the hyperarid Atacama core as surface water availability increased throughout this presently sterile landscape. Twenty-six radiocarbon dates indicate that these events occurred between 1050–680, 1615–1350 and 2500–2040 cal yr BP. Regional comparisons with rodent middens and other records suggest that these events were synchronous with pluvial stages detected at higher-elevations in the central Andes over the last 2500 yr. These hydroclimate changes also coincide with periods of pronounced SST gradients in the Tropical Pacific (La Niña-like mode), conditions that are conducive to significantly increased rainfall in the central Andean highlands and flood events in the low-elevation watersheds at inter-annual timescales. Our findings indicate that the positive anomalies in the hyperarid Atacama over the past 2500 yr represent a regional response of the central Andean climate system to changes in the global hydrological cycle at centennial timescales. Furthermore, our results provide support for the role of tropical Pacific sea surface temperature gradient changes as the primary mechanism responsible for climate fluctuations in the central Andes. Finally, our results constitute independent evidence for comprehending the major trends in cultural evolution of prehistoric peoples that inhabited the region.

scholarly journals Interglacial Beds at Toronto, Ontario

2007 ◽  
Vol 44 (3) ◽  
pp. 289-297 ◽  
Author(s):  
Paul F. Karrow
Keyword(s):  
Twentieth Century ◽  
Amino Acid ◽  
Lacustrine Sediments ◽  
Plant Macrofossils ◽  
Cold Climate ◽  
Quarter Century ◽  
Radiocarbon Dates ◽  
The Past ◽  
Late Wisconsinan ◽  
Paleontological Study

ABSTRACT Interglacial sediments have been known to occur at Toronto for about a century. There have been two main periods of attention: first by A. P. Coleman in the early twentieth century; and second mostly by the author and co-workers in the past quarter century. Attention was focussed early on the Don Formation because of its rich fossil assemblages. The Don Formation, consisting of gravel, sand, and clay, is commonly 6 to 9 m thick and has been encountered in outcrop only along the DonValley. However, excavations and borings indicate its presence under much of southern Metropolitan Toronto; it may continue northward along the Laurentian River Valley. Its only continuing, accessible exposure has been the Don Valley Brickyard. Early paleontological study emphasized molluscs, wood, leaves, and a few bones, which suggested a climate warmer than present. More recent studies have stressed microfossils. including pollen, diatoms, ostracodes. molluscs, Cladocera, insects, plant macrofossils, and microvertebrates. Altogether about 500 species have been identified, and the list is growing. Climatic indicators show that the Don Formation represents the declining temperatures of the waning half of an interglaciation. Although the Don Formation is beyond the range of radiocarbon dates and is undated, amino acid analysis on wood and shells support assignment to Sangamonian time. The overlying Scarborough Formation clay and sand, and the Pottery Road Formation sand contain mainly cold-climate fossils. These are in turn overlain by Early, Middle, and Late Wisconsinan tills and interbedded lacustrine sediments with corresponding radiocarbon and thermoluminescence (TL) dates.

Denouement: World Politics, Systemic Leadership, and Climate Change

2018 ◽  
Author(s):  
William R. Thompson ◽  
Leila Zakhirova
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
World Politics ◽  
First Century ◽  
Modern World ◽  
Climate Fluctuations ◽  
The Past ◽  
Agrarian Economy ◽  
Historical Processes

In this final chapter, we conclude by recapitulating our argument and evidence. One goal of this work has been to improve our understanding of the patterns underlying the evolution of world politics over the past one thousand years. How did we get to where we are now? Where and when did the “modern” world begin? How did we shift from a primarily agrarian economy to a primarily industrial one? How did these changes shape world politics? A related goal was to examine more closely the factors that led to the most serious attempts by states to break free of agrarian constraints. We developed an interactive model of the factors that we thought were most likely to be significant. Finally, a third goal was to examine the linkages between the systemic leadership that emerged from these historical processes and the global warming crisis of the twenty-first century. Climate change means that the traditional energy platforms for system leadership—coal, petroleum, and natural gas—have become counterproductive. The ultimate irony is that we thought that the harnessing of carbon fuels made us invulnerable to climate fluctuations, while the exact opposite turns out to be true. The more carbon fuels are consumed, the greater the damage done to the atmosphere. In many respects, the competition for systemic leadership generated this problem. Yet it is unclear whether systemic leadership will be up to the task of resolving it.

scholarly journals Calibration of Radiocarbon Dates for the Late Pleistocene Using U/Th Dates on Stalagmites

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-32 ◽  
Author(s):  
John C. Vogel ◽  
Joel Kronfeld
Keyword(s):  
South Africa ◽  
Magnetic Dipole ◽  
Satisfactory Agreement ◽  
Late Pleistocene ◽  
Calibration Curve ◽  
Dipole Field ◽  
Radiocarbon Dates ◽  
The Past ◽  
The Earth ◽  
Magnetic Dipole Field

Twenty paired 14C and U/Th dates covering most of the past 50,000 yr have been obtained on a stalagmite from the Cango Caves in South Africa as well as some additional age-pairs on two stalagmites from Tasmania that partially fill a gap between 7 ka and 17 ka ago. After allowance is made for the initial apparent 14C ages, the age-pairs between 7 ka and 20 ka show satisfactory agreement with the coral data of Bard et al. (1990, 1993). The results for the Cango stalagmite between 25 ka and 50 ka show the 14C dates to be substantially younger than the U/Th dates except at 49 ka and 29 ka, where near correspondence occurs. The discrepancies may be explained by variations in 14C production caused by changes in the magnetic dipole field of the Earth. A tentative calibration curve for this period is offered.

scholarly journals Colors and dyes of archaeological textiles from Tarapacá in the Atacama Desert (South Central Andes)

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Marcela Sepúlveda ◽  
Cecilia Lemp Urzúa ◽  
José Cárcamo-Vega ◽  
Edgar Casanova-Gónzalez ◽  
Sebastián Gutiérrez ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Raw Materials ◽  
Physicochemical Characterization ◽  
Atacama Desert ◽  
Central Andes ◽  
Formative Period ◽  
Animal Origin ◽  
Carminic Acid ◽  
Cultural Traditions ◽  
South Central

AbstractThis work concerns the study of colors and dyes identified on archaeological textiles from the Atacama Desert. The different garments and ornaments come from the excavation of two important pre-Columbian cemeteries of the Tarapacá region: Tarapacá-40 attributed to the Formative period (1100 BC–660 AD) and Pica-8 to the Late Intermediate period (900–1450 AD). For the first time, a multi-analytical approach with non-invasive techniques using FORS and SERS was applied on samples of less than 2 cm of length for physicochemical characterization of the raw materials and the dyes employed in the textile production of northern Chile. The fibers are from animal origin. Blue, green, and yellow are identified as indigo, but we cannot discard a mixture with other dyes to vary hue and shade; while carminic acid and alizarin—to a lesser extent—are found on red, orange, and brown samples. This research provides new elements for the discussion about the textile technology developed in this desertic region, its changes, and continuities along the history. Our results are compared to recent findings on neighboring regions from South-Central Andes, to improve the current knowledge and discuss the existence of dyeing textile cultural traditions.

Rattus exulans (Pacific rat).

2021 ◽  
Author(s):  
Aaron Shiels
Keyword(s):  
Southeast Asia ◽  
Bird Species ◽  
Tropical Pacific ◽  
Pacific Basin ◽  
The Past ◽  
The Pacific ◽  
Ground Nesting ◽  
The Tropical Pacific

Abstract The Pacific rat, R. exulans, is an major agricultural and environmental pest in parts of Southeast Asia and the Pacific. Thought to have spread with Polynesian colonists over the past several thousand years, it is now found through much of the Pacific basin, and is extensively distributed in the tropical Pacific. It poses a significant threat to indigenous wildlife, particularly ground-nesting birds, and has been linked to the extinction of several bird species. R. exulans may also transmit diseases to humans.

De-icing landsystem model for the Universidad Glacier (34° S) in the Central Andes of Chile during the past ~660 years

Geomorphology ◽  
2022 ◽  
pp. 108096
Author(s):  
Hans Fernández ◽  
Juan-Luis García ◽  
Samuel U. Nussbaumer ◽  
Alessa Janine Geiger ◽  
Isabelle Gärtner-Roer ◽  
...  
Keyword(s):  
Central Andes ◽  
The Past

The Paleoepidemiology of American Trypasonomiasis (Chagas disease)

1970 ◽  
Vol 80 (1) ◽  
Author(s):  
Wilmar Salo ◽  
William C. Auferheide ◽  
Michael Madden ◽  
John Streitz ◽  
Jane Buikstra ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Ancient Dna ◽  
Academic Discipline ◽  
Atacama Desert ◽  
Geographic Area ◽  
Northern Chile ◽  
Kinetoplast Dna ◽  
Testing Hypotheses ◽  
The Past ◽  
Tissue Specimens

Ancient DNA methodology was applied to extract and amplify a segment of kinetoplast DNA of Trypanosoma cruzi in soft tissue specimens from about 300 spontaneously mummified human bodies from the Atacama Desert in northern Chile and southern Peru. A DNA probe was then employed to hybridize with the amplicon. Results indicate that about 41% of the population in that geographic area were infected with the trypanosome over the past 9000 years. The epidemiological implications of these findings are discussed. It is also emphasized that this and several other paleoepidemiological studies in progress have established that population-study cohorts of mummies now can generate statistically valid paleoepidemiological investigations capable of testing hypotheses. These reflect the maturation of the academic discipline of the scientific study of mummies.

Past and recent biodiversity profiling in ancient Lake Chalco Mexico by a metagenomics analysis

2021 ◽  
Author(s):  
Bárbara Moguel ◽  
Liseth Pérez ◽  
Luis David Alcaraz ◽  
Socorro Lozano-García ◽  
Luis Herrera-Estrella ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Environmental Dna ◽  
Radiocarbon Dates ◽  
The Past ◽  
Mexican Volcanic Belt ◽  
History Of ◽  
High Throughput Dna Sequencing ◽  
High Altitude Lake ◽  
Taxonomic Groups ◽  
The Relationship

<p>For decades, paleoecological studies in lake sediments have focused on reconstructing the environments of the past and explaining phenomena linked to climatic variations. Recent advances in high-throughput DNA sequencing have allowed access to environmental DNA (eDNA) and ancient sedimentary DNA (sedaDNA) as a new and efficient proxy for past and present biodiversity. The basin of Mexico (BM) is located in the central part of the Trans-Mexican Volcanic Belt at 2,200 m a.s.l.; with the southern portion harboring the Chalco sub-basin. Lake Chalco is one of the last remaining natural aquatic ecosystems within the ever-expanding urban area surrounding Mexico City. The paleoenvironmental history of this lake has been previously characterized using sedimentological and geochemical proxies, as well as preserved microfossils (diatoms, pollen) with a temporal framework based on multiple radiocarbon dates. However, information for the remaining taxonomic groups and metabolic pathways remained unexplored. Here, we present the first metagenomics-based study for the Holocene in a high-altitude lake in Central Mexico –Lake Chalco. We explored the relationship between the lake’s paleoenvironmental condition and estimations of taxonomic and metabolic profiles across the sedimentary sequence (2.5 meters long). Multiple biological and abiotic variables revealed three main environmental phases: 1) a cool freshwater lake (FW1: 11,500-11,000 cal years BP), 2) a warm hyposaline lake (HS2: 11,000-6,000 cal years BP), and 3) a temperate, subsaline lake (SS3, <6,000 cal years BP). We describe the structure of the microbiota community and taxonomy richness turnover in the three Holocene paleoenvironmental phases. During the past 12 000 years BP the most abundant domains in Lake Chalco sediments were Bacteria, followed by Archaea, and Eukarya (36,722 genera). The analysis of functional proteins showed high biodiversity with a total of 27,636,243 proteins identified, but it was only possible to annotate 3,227,398 of them. Also, we identified several genes associated with some relevant pathways, such as methanogenesis. Altogether, this study allowed us to reconstruct the natural history of lake Chalco and its surroundings.</p>

Late-Holocene Formation of Lake Michigan Beach Ridges Correlated with a 70-yr Oscillation in Global Climate

1996 ◽  
Vol 45 (3) ◽  
pp. 321-326 ◽  
Author(s):  
Paul A. Delcourt ◽  
William H. Petty ◽  
Hazel R. Delcourt
Keyword(s):  
Late Holocene ◽  
Lake Michigan ◽  
Global Climate ◽  
Temperature Oscillation ◽  
Beach Ridges ◽  
Climate Fluctuations ◽  
The Past ◽  
Fundamental Part ◽  
Atmosphere System ◽  
Centennial Time Scale

AbstractA radiocarbon-dated series of 75 beach ridges, formed at regular intervals averaging 72 yr over the past 5400 yr, provides further support for the existence of a 70-yr oscillation in Northern Hemisphere climate, postulated recently from instrument data representing less than two cycles of this climate oscillation. Results from this study lend support to the interpretation that internal variations in the ocean–atmosphere system are an important factor in climate fluctuations on a decadal–centennial time scale. A temperature oscillation with a period of about 70 yr has been a previously unrecognized but fundamental part of the global climate system since at least the middle Holocene.

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