scholarly journals Late Glacial–Holocene climatic transition record at the Argentinian Andean piedmont between 33 and 34° S

2014 ◽  
Vol 10 (2) ◽  
pp. 863-875 ◽  
Author(s):  
A. E. Mehl ◽  
M. A. Zárate
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Early Holocene ◽  
South American ◽  
Aeolian Deposits ◽  
The Andes ◽  
Climatic Transition ◽  
Flooding Events

Abstract. The Arroyo La Estacada (~ 33°28' S, 69°02' W), eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant Late Pleistocene–early Holocene (LP–EH) alluvial sequence that includes several paleosols. One of these paleosols developed affecting the topmost part of likely Late Glacial aeolian deposits aggraded into a floodplain environment by the end of the Late Pleistocene. The paleosol shows variable grade of development along the arroyo outcrops. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, renewed alluvial aggradation and high magnitude flooding events affected the arroyo's floodplain environment. Accordignly, a period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP–EH transition in response to the climatic conditions in the Andes cordillera piedmont after the Late Glacial arid conditions. The analyzed Late Glacial–Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP–EH climatic transition in the extra-Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other pedosedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

scholarly journals Late Glacial-Holocene climatic transition record at the Argentinian Andean piedmont between 33–34° S

2013 ◽  
Vol 9 (5) ◽  
pp. 6125-6160
Author(s):  
A. E. Mehl ◽  
M. A. Zárate
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Late Glacial ◽  
Early Holocene ◽  
South American ◽  
The South ◽  
Sedimentary Sequences ◽  
Aeolian Deposits ◽  
Climatic Transition ◽  
Flooding Events

Abstract. The Arroyo La Estacada (~33°28' S, 69°02' W), eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant late Pleistocene–early Holocene (LP–EH) alluvial sequence including several paleosols. The arroyo sedimentary record exhibits a paleosol developed affecting the topmost part of likely Lateglacial aeolian deposits aggraded into a floodplain environment by the end of the late Pleistocene. The paleosol shows variable grade of development in the outcrops along the arroyo probably in relation to fluvial valley paleotopography. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, alluvial aggradation renewed and a higher frequency of flooding events could have affected the arroyo's floodplain environment. A period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP–EH transition in response to a climatic amelioration in the Andes cordillera piedmont after the Late Glacial arid conditions. The renewal of early Holocene alluvial aggradation was probably influenced by the South American Monsoon and resulted in a change in the sedimentary dynamics of the arroyo. The analyzed Late Glacial-Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP–EH climatic transition at the extra Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other sedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

scholarly journals Late Pleistocene and Early Holocene aeolian deposits of Tasmania and their climatic implications – Corrigendum

2021 ◽  
pp. 1-2
Author(s):  
Peter D. McIntosh ◽  
Christina Neudorf ◽  
Olav B. Lian ◽  
Adrian J. Slee ◽  
Brianna Walker ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Early Holocene ◽  
Aeolian Deposits

scholarly journals How dry was the Younger Dryas? Evidence from a coupled <i>δ</i><sup>2</sup>H–<i>δ</i><sup>18</sup>O biomarker paleohygrometer applied to the Gemündener Maar sediments, Western Eifel, Germany

2019 ◽  
Vol 15 (2) ◽  
pp. 713-733 ◽  
Author(s):  
Johannes Hepp ◽  
Lorenz Wüthrich ◽  
Tobias Bromm ◽  
Marcel Bliedtner ◽  
Imke Kathrin Schäfer ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Younger Dryas ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Leaf Water ◽  
Early Holocene ◽  
Unexpected Finding ◽  
Temperature Dependent ◽  
The Past ◽  
Natural Climate

Abstract. Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 and C29) and a hemicellulose-derived sugar biomarker (arabinose), respectively. Both δ2Hn-alkane and δ18Osugar are suggested to reflect mainly leaf water of vegetation growing in the catchment of the Gemündener Maar. Leaf water reflects δ2H and δ18O of precipitation (primarily temperature-dependent) modified by evapotranspirative enrichment of leaf water due to transpiration. Based on the notion that the evapotranspirative enrichment depends primarily on relative humidity (RH), we apply a previously introduced “coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach” to reconstruct the deuterium excess of leaf water and in turn Late Glacial–Early Holocene RH changes from our Gemündener Maar record. Our results do not provide evidence for overall markedly dry climatic conditions having prevailed during the Younger Dryas. Rather, a two-phasing of the Younger Dryas is supported, with moderate wet conditions at the Allerød level during the first half and drier conditions during the second half of the Younger Dryas. Moreover, our results suggest that the amplitude of RH changes during the Early Holocene was more pronounced than during the Younger Dryas. This included the occurrence of a “Preboreal Humid Phase”. One possible explanation for this unexpected finding could be that solar activity is a hitherto underestimated driver of central European RH changes in the past.

Expansion of Magellanic Moorland during the Late Pleistocene: Palynological Evidence from Northern Isla de Chiloé, Chile

1988 ◽  
Vol 30 (3) ◽  
pp. 304-314 ◽  
Author(s):  
Carolina Villagrán
Keyword(s):  
Late Pleistocene ◽  
Late Quaternary ◽  
Marked Change ◽  
Climatic Conditions ◽  
Annual Precipitation ◽  
Palynological Analysis ◽  
Wetland Development ◽  
Average Temperature ◽  
Rio Negro

The late Quaternary vegetation of northern Isla de Chiloé is inferred from palynological analysis of a section in the Río Negro drainage (42°03′S, 73°50′W). At ca. 30,500 yr B.P., maxima of Astelia and Donatia occurred, suggesting wetland development. From that time until ca. 27,000 yr B.P., steppe indicators such as Compositae/Gramineae dominated, suggesting drier conditions. After 27,000 yr B.P., the moorland shrub Dacrydium gradually increased, reaching a maximum by 18,000 yr B.P. At this time Astelia increased again, suggesting development of cushion bog during cold and wet conditions. The glacial-postglacial transition is characterized by a marked change from peaty sediments to clays, a decrease in the cushion bog flora, and the prevalence of Gramineae/ Compositae and swamp taxa. This vegetation prevailed until ca.7000 yr B.P. when forest taxa became dominant. The floristic pattern inferred from the pollen spectra of the Rio Negro section suggests that the late Pleistocene vegetation of Chiloé resembled modern Magellanic Moorland vegetation (52°–56°lat S). Based on climatic conditions presently associated with Magellanic Moorland, its occurrence in Chiloé at low elevations during the late Pleistocene implies a decrease in average temperature of at least 4°C and an increase in annual precipitation of at least 1500 mm.

scholarly journals Climate warming and humans played different roles in triggering Late Quaternary extinctions in east and west Eurasia

2017 ◽  
Vol 284 (1851) ◽  
pp. 20162438 ◽  
Author(s):  
Xinru Wan ◽  
Zhibin Zhang
Keyword(s):  
Climate Change ◽  
Late Pleistocene ◽  
Climate Warming ◽  
Human Impacts ◽  
Late Quaternary ◽  
Extinction Risk ◽  
Early Holocene ◽  
Large Mammals ◽  
Predominant Factor ◽  
Late Pleistocene To Holocene

Climate change and humans are proposed as the two key drivers of total extinction of many large mammals in the Late Pleistocene and Early Holocene, but disentangling their relative roles remains challenging owing to a lack of quantitative evaluation of human impact and climate-driven distribution changes on the extinctions of these large mammals in a continuous temporal–spatial dimension. Here, our analyses showed that temperature change had significant effects on mammoth (genus Mammuthus ), rhinoceros (Rhinocerotidae), horse (Equidae) and deer (Cervidae). Rapid global warming was the predominant factor driving the total extinction of mammoths and rhinos in frigid zones from the Late Pleistocene and Early Holocene. Humans showed significant, negative effects on extirpations of the four mammalian taxa, and were the predominant factor causing the extinction or major extirpations of rhinos and horses. Deer survived both rapid climate warming and extensive human impacts. Our study indicates that both the current rates of warming and range shifts of species are much faster than those from the Late Pleistocene to Holocene. Our results provide new insight into the extinction of Late Quaternary megafauna by demonstrating taxon-, period- and region-specific differences in extinction drivers of climate change and human disturbances, and some implications about the extinction risk of animals by recent and ongoing climate warming.

Late Quaternary Climate and Vegetation of the Sudanian Zone of Northeast Nigeria

2002 ◽  
Vol 58 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Ulrich Salzmann ◽  
Philipp Hoelzmann ◽  
Irena Morczinek
Keyword(s):  
Environmental History ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Climatic Conditions ◽  
Lake Levels ◽  
The Holocene ◽  
Quaternary Climate ◽  
History Of ◽  
Sudanian Zone ◽  
Humid Period

AbstractThe Lake Tilla crater lake in northeastern Nigeria (10°23′N, 12°08′E) provides a ca. 17,000 14C yr multiproxy record of the environmental history of a Sudanian savanna in West Africa. Evaluation of pollen, diatoms, and sedimentary geochemistry from cores suggests that dry climatic conditions prevailed throughout the late Pleistocene. Before the onset of the Holocene, the slow rise in lake levels was interrupted by a distinct dry event between ca. 10,900 and 10,500 14C yr B.P., which may coincide with the Younger Dryas episode. The onset of the Holocene is marked by an abrupt increase in lake levels and a subsequent spread of Guinean and Sudanian tree taxa into the open grass savanna that predominated throughout the Late Pleistocene. The dominance of the mountain olive Olea hochstetteri suggests cool climatic conditions prior to ca. 8600 14C yr B.P. The early to mid-Holocene humid period culminated between ca. 8500 and 7000 14C yr B.P. with the establishment of a dense Guinean savanna during high lake levels. Frequent fires were important in promoting the open character of the vegetation. The palynological and palaeolimnological data demonstrate that the humid period terminated after ca. 7000 14C yr B.P. in a gradual decline of the precipitation/evaporation ratio and was not interrupted by abrupt climatic events. The aridification trend intensified after ca. 3800 14C yr B.P. and continued until the present.

Late Pleistocene coastal paleogeography of the Queen Charlotte Islands, British Columbia, Canada, and its implications for terrestrial biogeography and early postglacial human occupation

2003 ◽  
Vol 40 (12) ◽  
pp. 1755-1766 ◽  
Author(s):  
Renée Hetherington ◽  
J Vaughn Barrie ◽  
Robert GB Reid ◽  
Roger MacLeod ◽  
Dan J Smith ◽  
...  
Keyword(s):  
British Columbia ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Glacial Refugia ◽  
Spatial Modelling ◽  
Early Holocene ◽  
Human Occupation ◽  
Land Bridge ◽  
Sea Levels ◽  
Queen Charlotte Islands

Molluscs, sediment lithology, and published sub-bottom profiles are used to deduce sea levels, outline the influence of glacially induced crustal displacement, and reconstruct the paleoenvironment of the northeast Pacific late Quaternary coastline. Geo-spatial modelling shows subaerially exposed land that could have been inhabited by plants and animals, and also coastally migrating early North American peoples. Ice-free terrain, present by at least 13 790 ± 150 14C years BP, a land bridge, and edible molluscs are identified. Queen Charlotte Islands (QCI) late Pleistocene coastal paleogeography may assist in explaining the biogeography of many terrestrial plant and animal species along the broader northeastern Pacific margin and provide evidence for researchers seeking late Pleistocene – early Holocene glacial refugia. Late Pleistocene – early Holocene coastlines that are not drowned and that may harbour early archaeological sites are identified along the western QCI, where migrants probably first travelled and the westernmost British Columbia mainland, where the effects of glacial ice were reduced.

Late Pleistocene and early Holocene environmental history of southwestern Washington State, U.S.A.

1984 ◽  
Vol 21 (6) ◽  
pp. 619-629 ◽  
Author(s):  
Cathy W. Barnosky
Keyword(s):  
Environmental History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Cascade Range ◽  
Early Holocene ◽  
Olympic Mountains ◽  
Tundra Vegetation ◽  
Plant Remains ◽  
History Of ◽  
Glacial Time

A comparison of pollen records and associated plant remains from sites along a major precipitation gradient in southwestern Washington enables reconstruction of the late Quaternary environment during glacial and early Holocene time. During the Evans Creek Stade (25 000 – 17 000 years BP) little moisture reached lowlands east of the Olympic Mountains and as a result both the Puget Trough and the Columbia Basin featured a cold dry climate and parkland–tundra vegetation In glacial time, greatest aridity seems to have occurred between 19 000 and 17 000 years BP. After 17 000 years BP the development of mesophytic subalpine parkland suggests that maritime conditions extended farther east into the Puget Trough, and the Cascade Range became an important precipitation divide. Conditions warmer and (or) drier than today developed throughout western Washington between 10 000 and 8000–6000 years BP. Vegetation on opposite sides of the Cascade Range became dissimilar as early as 17 000 years BP, but this trend was accentuated in late glacial and early Holocene time.

scholarly journals Late Glacial and Early Holocene human demographic responses to climatic and environmental change in Atlantic Iberia

2020 ◽  
Vol 376 (1816) ◽  
pp. 20190724 ◽  
Author(s):  
T. Rowan McLaughlin ◽  
Magdalena Gómez-Puche ◽  
João Cascalheira ◽  
Nuno Bicho ◽  
Javier Fernández-López de Pablo
Keyword(s):  
Population Growth ◽  
Quantitative Methods ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Early Holocene ◽  
Food Sources ◽  
Resource Base ◽  
Temporal Models ◽  
Spatio Temporal ◽  
Successive Generations

Successive generations of hunter–gatherers of the Late Glacial and Early Holocene in Iberia had to contend with rapidly changing environments and climatic conditions. This constrained their economic resources and capacity for demographic growth. The Atlantic façade of Iberia was occupied throughout these times and witnessed very significant environmental transformations. Archaeology offers a perspective on how past human population ecologies changed in response to this scenario. Archaeological radiocarbon data are used here to reconstruct demographics of the region over the long term. We introduce various quantitative methods that allow us to develop palaeodemographic and spatio-temporal models of population growth and density, and compare our results to independent records of palaeoenvironmental and palaeodietary change, and growth rates derived from skeletal data. Our results demonstrate that late glacial population growth was stifled by the Younger Dryas stadial, but populations grew in size and density during the Early to Middle Holocene transition. This growth was fuelled in part by an increased dependence on marine and estuarine food sources, demonstrating how the environment was linked to demographic change via the resource base, and ultimately the carrying capacity of the environment. This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography’.

scholarly journals Bedrock Control on Glacial Limits: Examples from the Ladakh and Zanskar Ranges, North-Western Himalaya, India

1985 ◽  
Vol 31 (108) ◽  
pp. 143-149 ◽  
Author(s):  
Douglas W. Burbank ◽  
Monique B. Fort
Keyword(s):  
Late Pleistocene ◽  
Western Himalaya ◽  
Late Glacial ◽  
Climatic Conditions ◽  
River Valley ◽  
Equilibrium Line ◽  
Indus River ◽  
The North ◽  
North Western ◽  
Glacial Advance

AbstractIn the north-western Himalaya, the distribution of modem glaciers and snowlines in the Ladakh and Zanskar Ranges adjacent to the Indus River valley suggests comparable climatic conditions prevail in the two ranges. Similarly, the positions of terminal moraines and reconstructed equilibrium-line altitudes (ELAs) indicate equivalent magnitudes of Neoglacial and Late Glacial advances in both ranges. However, the terminal positions and reconstructed ELAs from the late Pleistocene maximum advances are at least 400 m lower in the Ladakh Range than in the nearby Zanskar Range. These differences do not appear to reflect either climatic or tectonic controls. Rather, they are caused by an unusual bedrock configuration in the Zanskar Range, where vertical strata of indurated sandstones and conglomerates, and narrow steep-walled canyons cut through them, created a bulwark that effectively precluded significant down-valley advance. Without recognition of this physical impedance to glacial advance, uncritical reconstructions would greatly overestimate the altitude of the ELA in the Zanskar Range.

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