scholarly journals ASSESSING THE EARLY HOLOCENE ENVIRONMENT OF NORTHWESTERN GUYANA: AN ISOTOPIC ANALYSIS OF HUMAN AND FAUNAL REMAINS

2018 ◽  
Vol 29 (2) ◽  
pp. 279-292
Author(s):  
Louisa Daggers ◽  
Mark G. Plew ◽  
Alex Edwards ◽  
Samantha Evans ◽  
Robin B. Trayler
Keyword(s):  
Isotopic Analysis ◽  
Human Bone ◽  
Early Holocene ◽  
Stable Carbon ◽  
Faunal Remains ◽  
Plant Availability ◽  
The Holocene ◽  
The Past ◽  
Early Archaic ◽  
O Isotope

This study uses stable carbon δ13C and oxygen δ18O isotope compositions data to assess the extent to which diet breadths of northwestern Guyana changed during the Holocene. We analyzed human bone and enamel remains from seven shell mound sites dating between 7500 and 2600 BP. Our analyses demonstrate some constancy in C3 plant availability during the past several thousand years, though we note increasing reliance on such plants beginning in the Early Holocene. We also document warming intervals during the Early Holocene (Early Archaic) that appear to correlate with dry periods known elsewhere in the central Amazon during this period.

The Underwater Archaeology of Paleolandscapes, Apalachee Bay, Florida

2004 ◽  
Vol 69 (2) ◽  
pp. 275-289 ◽  
Author(s):  
Michael K. Faught
Keyword(s):  
Continental Shelf ◽  
Late Pleistocene ◽  
Settlement Patterns ◽  
Early Holocene ◽  
Faunal Remains ◽  
Middle Holocene ◽  
Early Archaic ◽  
Archaeological Methods ◽  
Middle Archaic ◽  
Aucilla River

Submerged prehistoric sites investigated in northwest Florida along the margins of the drowned Aucilla River channel (or PaleoAucilla) extend our understanding of prehistoric settlement patterns and paleolandscape utilization. Bifacial and unifacial tools indicate Late Paleoindian and Early Archaic logistical activities at these sites, as well as later Middle Archaic occupations. Other evidence for terrestrial conditions at these sites include extinct and extant terrestrial faunal remains, in-place tree stumps, and possible eroded middle Holocene shell middens. This report outlines the methodologies used for site investigations, and then discusses the geomorphic setting, character, cultural-historical connections, and timing of full inundation for these offshore sites. During late Pleistocene and early Holocene times, the coastline was much farther out on the continental shelf, and this segment of the PaleoAucilla was forested and well inland. Later, during the middle Holocene stages of transgression, the segment was more of a wide grassy marsh with brackish water tidal creeks and oysters. In this continental shelf setting, submerged archaeological sites remain in clustered arrays accessible by underwater archaeological methods, and the data provide a critical supplement to our present understanding of late Pleistocene and early Holocene settlement patterns and paleolandscape utilization.

scholarly journals The effect of a Holocene climatic optimum on the evolution of the Greenland ice sheet during the last 10 kyr

2018 ◽  
Vol 64 (245) ◽  
pp. 477-488 ◽  
Author(s):  
LISBETH T. NIELSEN ◽  
GUðFINNA AÐALGEIRSDÓTTIR ◽  
VASILEIOS GKINIS ◽  
ROMAN NUTERMAN ◽  
CHRISTINE S. HVIDBERG
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Climate Forcing ◽  
The Holocene ◽  
The Past ◽  
Holocene Climatic Optimum ◽  
Surface Temperatures ◽  
Climatic Optimum

ABSTRACTThe Holocene climatic optimum was a period 8–5 kyr ago when annual mean surface temperatures in Greenland were 2–3°C warmer than present-day values. However, this warming left little imprint on commonly used temperature proxies often used to derive the climate forcing for simulations of the past evolution of the Greenland ice sheet. In this study, we investigate the evolution of the Greenland ice sheet through the Holocene when forced by different proxy-derived temperature histories from ice core records, focusing on the effect of sustained higher surface temperatures during the early Holocene. We find that the ice sheet retreats to a minimum volume of ~0.15–1.2 m sea-level equivalent smaller than present in the early or mid-Holocene when forcing an ice-sheet model with temperature reconstructions that contain a climatic optimum, and that the ice sheet has continued to recover from this minimum up to present day. Reconstructions without a warm climatic optimum in the early Holocene result in smaller ice losses continuing throughout the last 10 kyr. For all the simulated ice-sheet histories, the ice sheet is approaching a steady state at the end of the 20th century.

Variability of 14C reservoir age and air–sea flux of CO2 in the Peru–Chile upwelling region during the past 12,000 years

2016 ◽  
Vol 85 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Matthieu Carré ◽  
Donald Jackson ◽  
Antonio Maldonado ◽  
Brian M. Chase ◽  
Julian P. Sachs
Keyword(s):  
Carbon Flux ◽  
Late Holocene ◽  
Early Holocene ◽  
Northern Chile ◽  
Oceanic Circulation ◽  
Central Chile ◽  
The Holocene ◽  
Southern Peru ◽  
The Past ◽  
Reservoir Age

The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile (~ 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air–sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air–sea carbon flux in this region.

High-resolution evidence from southern China of an early holocene optimum and a mid-Holocene dry event during the Past 18,000 Years

2004 ◽  
Vol 62 (1) ◽  
pp. 39-48 ◽  
Author(s):  
Weijian Zhou ◽  
Xuefeng Yu ◽  
A.J. Timothy Jull ◽  
G. Burr ◽  
J.Y. Xiao ◽  
...  
Keyword(s):  
High Resolution ◽  
Southern China ◽  
Asian Summer Monsoon ◽  
Early Holocene ◽  
Central China ◽  
Pressure System ◽  
Southern Boundary ◽  
Subtropical Zone ◽  
The Holocene ◽  
The Past

Computer models suggest that the Holocene Optimum for East Asian summer monsoon precipitation occurred at different times in different regions of China. Previous studies indicate that this time-transgressive Holocene Optimum should have been experienced about 3000 yr ago in southern China. In this study we describe a section which allows us to test this timing directly. We have closely examined high-resolution eutrophic peat/mud sequences covering the past 18,000 cal yr at Dahu, Jiangxi, on the southern boundary of the mid subtropical zone in China. Late Pleistocene successions in the Dahu record indicate cooler and much wetter conditions relative to synchronous events in north-central China. Our results indicate that the Holocene Optimum occurred between ca. 10,000 and 6000 cal yr ago in southern China, consistent with the global pattern. Conditions were relatively dry and cold from 6000 to 4000 cal yr ago. Our data also support the conclusion that the last deglaciation to early Holocene in the south was much wetter, resulting in the formation of dense broad-leaved forests, which could have acted to moderate land temperature ∼10,000 to 6000 cal yr ago, yielding a stable early-Holocene climate. After 6000 cal yr, forest reduction led to unstable land temperatures, and possibly to a northerly shift of the subtropical high-pressure system. Whatever the mechanism, these changes resulted in decreased precipitation between 6000 and 4000 cal yr B.P. in southern China.

Small Sambaquis and Big Chronologies: Shellmound Building and Hunter-Gatherers in Neotropical Highlands

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1215-1221 ◽  
Author(s):  
Levy Figuti ◽  
Cláudia R Plens ◽  
Paulo DeBlasis
Keyword(s):  
Human Bone ◽  
Cultural Continuity ◽  
Cultural Tradition ◽  
Archaeological Research ◽  
Faunal Remains ◽  
Research Project ◽  
Hunter Gatherers ◽  
C Distribution ◽  
Bone Remains

Sambaquis, famous Brazilian coastal shellmounds, represent a successful and long archaeological cultural tradition, with hundreds of sites spread over 2000 km of the Brazilian south-southeast coastline. These sites have many burials within a sequence of layers comprising a mix of faunal remains, charcoal, ashes, and sand, thus resulting in very complex stratigraphic structures. Several radiocarbon samples exhibit ages between 8000 and 1000 cal yr BP. In the Brazilian southeastern coastal hinterland, at the Ribeira de Iguape basin, 36 small mounds similar to the sambaquis were found, composed mostly of landsnail shells, bone remains of terrestrial fauna, lithic and osteodontological artifacts, and quite a few burials. Through the last decade an archaeological research project has accomplished extensive surveys and systematic 14C sampling, together with excavations in selected sites. A sequence of ages has been obtained from different samples (16 on shell, 10 on human bone, and 6 on charcoal) representing 19 sites. These dates range from 10,000 to 1000 cal yr BP, highlighting around 9000 yr of cultural continuity, contemporary to both the Paleoindian record over the hinterland plateau, and older than their coastal counterparts, the sambaquis. By presenting the 14C distribution and an overview of the archaeological features of these sites, we discuss briefly the dispersion and settlement processes of early peopling in this area of Brazil.

Bone Cave: A Severely Disturbed Cave Site in Central Oregon

2005 ◽  
Vol 26 (2) ◽  
pp. 221-244 ◽  
Author(s):  
Jeffrey R. Ferguson ◽  
Craig E. Skinner
Keyword(s):  
Field Research ◽  
Archaeological Site ◽  
Time Span ◽  
Early Holocene ◽  
Political Environment ◽  
Limited Time ◽  
Faunal Remains ◽  
High Concentration ◽  
Processing Site ◽  
Disturbed Site

The presence of obsidian artifacts available for hydration and sourcing analysis, a high concentration of well-preserved faunal remains, a limited time span of occupation, and a wealth of obsidian research in the region, make Bone Cave an ideal example of an often ignored class of archaeological site. Although highly disturbed, analysis of the excavation results allowed us to determine that Bone Cave served as a probable pre-Mazama (prior to 6850 B.P.) rabbit processing site during the Early Holocene. The disturbed site of Bone Cave shows that field research is possible even in a region or political environment in which the excavation of intact sites is not.

Quaternary Hypsithermals

1972 ◽  
Vol 2 (3) ◽  
pp. 270-273 ◽  
Author(s):  
Cesare Emiliani
Keyword(s):  
High Temperature ◽  
Deep Sea ◽  
Isotopic Analysis ◽  
The Past ◽  
Absolute Dating ◽  
Oxygen Isotopic ◽  
Environmental Balance ◽  
Past Half ◽  
Oxygen Isotopic Analysis

Oxygen isotopic analysis and absolute dating of deep-sea cores show that temperatures as high as those of today occurred for only about 10% of the time during the past half million years. The shortness of the high temperature intervals (“hypsithermals”) suggests a precarious environmental balance, a condition which makes man's interference with the environment during the present hypsithermal extremely critical. This precarious balance must be stabilized if a new glaciation or total deglaciation is to be avoided.

The dynamics of Holocene monsoon based on meteoric 10Be at Kunlun Pass on the northeastern Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Peng Chen ◽  
Zhongbo Yu ◽  
Markus Czymzik ◽  
Ala Aldahan ◽  
Jinguo Wang ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Early Holocene ◽  
Tibet Plateau ◽  
The Holocene ◽  
Proxy Records ◽  
Low Levels ◽  
High Level ◽  
Qinghai Tibet Plateau

<p>Multiple proxy records have been used for the understanding of environmental and climate changes during the Holocene. For the first time, we here measure meteoric <sup>10</sup>Be isotope of sediments from a drill core collected at the Kunlun Pass (KP) on the northeastern Qinghai-Tibet Plateau (NETP) to investigate mositure and atmospheric circulation changes during the Holocene. The <sup>10</sup>Be flux suggests relative low levels in the Early Holocene, followed by a sharp increase to high values at around 4 ka BP (4 ka BP = 4000 years before present). Afterwards, the <sup>10</sup>Be flux remains on a high level during the Late Holocene, but decreases slightly towards today. These <sup>10</sup>Be deposition patterns are compared to moisture changes in regions dominated by the Indian Summer Monsoon (ISM), East Asian Summer Monsoon (EASM), and the Westerlies. Different from the gradual changes in monsoon patterns, the <sup>10</sup>Be data reveal low levels during the Early Holocene until ~4 ka BP when an obvious increase was indicated and a relative high level continues to this day, which is relatively more in agreement with patterns of the Westerlies. This finding provides a new evidence for a shift in the dominant pattern of atmospheric circulation at the KP region from a more monsoonal one to one dominated by the Westerlies. Our results improve the understanding of non-stationary interactions and spatial relevance of the EASM, the ISM and the Westerlies on the Qinghai-Tibet Plateau.</p>

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