Late Quaternary stratigraphy and geochronology of the western Killpecker Dunes, Wyoming, USA

2004 ◽  
Vol 61 (1) ◽  
pp. 72-84 ◽  
Author(s):  
James H. Mayer ◽  
Shannon A. Mahan
Keyword(s):  
Late Pleistocene ◽  
Great Plains ◽  
Little Ice Age ◽  
Late Quaternary ◽  
Soil Formation ◽  
Ice Age ◽  
Dune Field ◽  
Eolian Sand ◽  
Quaternary Stratigraphy ◽  
Precise Understanding

New stratigraphic and geochronologic data from the Killpecker Dunes in southwestern Wyoming facilitate a more precise understanding of the dune field’s history. Prior investigations suggested that evidence for late Pleistocene eolian activity in the dune field was lacking. However, luminescence ages from eolian sand of ∼15,000 yr, as well as Folsom (12,950–11,950 cal yr B.P.) and Agate Basin (12,600–10,700 cal yr) artifacts overlying eolian sand, indicate the dune field existed at least during the latest Pleistocene, with initial eolian sedimentation probably occurring under a dry periglacial climate. The period between ∼13,000 and 8900 cal yr B.P. was characterized by relatively slow eolian sedimentation concomitant with soil formation. Erosion occurred between ∼8182 and 6600 cal yr B.P. on the upwind region of the dune field, followed by relative stability and soil formation between ∼5900 and 2700 cal yr B.P. The first of at least two latest Holocene episodes of eolian sedimentation occurred between ∼2000 and 1500 yr, followed by a brief (∼500 yr) episode of soil formation; a second episode of sedimentation, occurring by at least ∼700 yr, may coincide with a hypothesized Medieval warm period. Recent stabilization of the western Killpecker Dunes likely occurred during the Little Ice Age (∼350–100 yr B.P.). The eolian chronology of the western Killpecker Dunes correlates reasonably well with those of other major dune fields in the Wyoming Basin, suggesting that dune field reactivation resulted primarily due to departures toward aridity during the late Quaternary. Similar to dune fields on the central Great Plains, dune fields in the Wyoming Basin have been active under a periglacial climate during the late Pleistocene, as well as under near-modern conditions during the latest Holocene.

Holocene eolian sand deposition linked to climatic variability, Northern Great Plains, Canada

The Holocene ◽  
2016 ◽  
Vol 27 (4) ◽  
pp. 579-593 ◽  
Author(s):  
Stephen A Wolfe ◽  
Olav B Lian ◽  
Christopher H Hugenholtz ◽  
Justine R Riches
Keyword(s):  
Great Plains ◽  
Climatic Variability ◽  
Sediment Cores ◽  
Soil Formation ◽  
Temporal Variations ◽  
Ice Age ◽  
Northern Great Plains ◽  
Eolian Sand ◽  
Sand Accumulation ◽  
Sand Deposition

The Bigstick and Seward Sand Hills are possibly two of the oldest dune fields within the late Wisconsin glaciated regions of the Northern Great Plains. As with most Northern Great Plains dune fields, source sediments are former proglacial outwash sands. Thus, Holocene dune construction is primarily related to spatial–temporal variations in surface cover and transport capacity, rather than renewed sediment input. However, eolian landscape reconstructions on the Northern Great Plains have been temporally constrained to recent periods of activity, as older episodes of deposition are typically reworked by younger events. In this study, sediment cores from shallow lacustrine basins and interdune areas provide an improved record of Holocene eolian sand deposition. Eolian sand accumulation in the interdunes and basins occurred between 150 and 270 years ago, 1.9 and 3.0 ka, 5.4 and 8.6 ka, and prior to ca. 10.8 ka. These episodes of sand accumulation were bracketed by lacustrine deposition and soil formation, which represented wetter conditions. Other than mid-Holocene dune activity, which may be related to peak warmth and aridity, most periods of eolian sand accumulation coincided with cooler but drier climatic events such as the Younger Dryas, late-Holocene cooling prior to the Medieval Climatic Anomaly, and the ‘Little Ice Age’. These depositional episodes are also spatially represented by other dune fields in the region, providing a broad-scale view of the connections between past climatic events and eolian landscape evolution on the Northern Great Plains.

scholarly journals Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age

2009 ◽  
Vol 6 (5) ◽  
pp. 835-848 ◽  
Author(s):  
D. Gutiérrez ◽  
A. Sifeddine ◽  
D. B. Field ◽  
L. Ortlieb ◽  
G. Vargas ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Decadal Variability ◽  
Late Quaternary ◽  
Walker Circulation ◽  
Rapid Expansion ◽  
Ice Age ◽  
Ecosystem Structure ◽  
Ocean Biogeochemistry ◽  
Ocean Ecosystem ◽  
Abrupt Shifts

Abstract. Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in the present-day higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.

scholarly journals A importância da acção do frio do Quaternário final em Portugal e suas implicações nas morfodinâmicas de vertente.

2012 ◽  
Vol 5 (2) ◽  
pp. 421
Author(s):  
António Sousa Pedrosa
Keyword(s):  
Little Ice Age ◽  
Late Quaternary ◽  
Climatic Conditions ◽  
Ice Age ◽  
Glacial Deposits ◽  
Central Portugal

Resumo   De entre os  factores que tiveram maior influência na evolução do relevo de Portugal no decurso final do Quaternário é incontestável que o frio e os processos que lhe estão associados tiveram um papel muito importante na modelação das formas de relevo. Neste trabalho procuraremos fazer uma síntese dos principais aspectos da evolução das vertentes relacionados com os frio, inferir através dos vestígios que chegaram até ao nossos dias quais as condições morfo-climáticas em que ocorreram e quais os processos que lhes estavam encontravam associados. Realçamos assim o papel da acção dos glaciares nas áreas onde ocorreram assim como a importância dos processos periglaciares na evolução das vertentes. O período tardiglaciar também se mostrou marcante na dinâmica de vertentes tendo mobilizado e remobilizado muito material nas vertentes através de solifluxões generalizadas levando muitas delas à sua regularização. O período conhecido como a pequena idade do gelo também deixou as suas marcas na dinâmica das vertentes às quais se associam as escombreiras de gravidade. Por fim enfatizamos um pouco o papel do frio na actual morfodinâmica de vertentes no Norte de Centro de Portugal.   Palavras-chave: Norte de Portugal; Montanhas, depósitos glaciares, depósitos periglaciares, dinâmica de vertentes Summary   Among the factors that most influenced the evolution of the relief of Portugal during the late Quaternary is incontestable that the cold and the processes associated with it had a very important role in modeling the forms of relief. In this paper, we will try to summarize the importance that the cold had on the evolution of slopes, inferred through the vestiges that have come down to our day, which morpho-climatic conditions in which they occur, and also what processes if they were associated with. Thus enhancing the role of action in areas where glaciers have occurred and the importance of periglacial processes in the evolution of the slopes. In tardiglaciar the dynamics of slopes was very active and mobilized a lot of material through the process of solifluction regularized many of them. The period known as the Little Ice Age has also left its mark on the dynamic slopes which relate to tailings heaps of gravity. Finally we emphasize the role of cold in the current slopes of morphodynamics in north and central Portugal.   Keywords: North of Portugal; mountains, glacial deposits, periglacial deposits, morphodynamics of slopes 

scholarly journals Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age

2008 ◽  
Vol 5 (5) ◽  
pp. 3919-3943 ◽  
Author(s):  
D. Gutiérrez ◽  
A. Sifeddine ◽  
D. B. Field ◽  
L. Ortlieb ◽  
G. Vargas ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Decadal Variability ◽  
Late Quaternary ◽  
Walker Circulation ◽  
Rapid Expansion ◽  
Ice Age ◽  
Ecosystem Structure ◽  
Ocean Biogeochemistry ◽  
Ocean Ecosystem ◽  
Abrupt Shifts

Abstract. Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.

Late Quaternary landscape evolution and bioclimatic change in the central Great Plains, USA

2020 ◽  
Vol 132 (11-12) ◽  
pp. 2553-2571
Author(s):  
Anthony L. Layzell ◽  
Rolfe D. Mandel
Keyword(s):  
Great Plains ◽  
Landscape Evolution ◽  
Late Quaternary ◽  
Stable Carbon Isotope ◽  
Soil Formation ◽  
River Valley ◽  
Sediment Supply ◽  
Alluvial Fans ◽  
Buried Soils ◽  
South Central

Abstract A systematic study of floodplains, terraces, and alluvial fans in the Republican River valley of south-central Nebraska provided a well-dated, detailed reconstruction of late Quaternary landscape evolution and resolved outstanding issues related to previously proposed Holocene terrace sequences. Stable carbon isotope (δ13C) values determined on soil organic matter from buried soils in alluvial landforms were used to reconstruct the structure of vegetation communities and provided a means to investigate the relationships between bioclimatic change and fluvial activity for the period of record. Our study serves as a model for geomorphological and geoarcheological investigations in stream valleys throughout the central Great Plains and wherever loess-derived late Quaternary alluvial fans occur, in particular. Holocene alluvial landforms in the river valley include a broad floodplain complex (T-0a, T-0b, and T-0c), a single alluvial terrace (T-1), and alluvial fans that mostly grade to the T-1 (AF-1) and T-0c (AF-0c) surfaces. Remnants of a late Pleistocene terrace (T-2), mantled by Holocene (Bignell) loess, are also preserved, and some Holocene alluvial fans (AF-2) grade to T-2 surfaces. Radiocarbon ages suggest that the T-1 fill and AF-1 fans aggraded between ca. 9000–1000 yr B.P. Hence, nearly all of the Holocene alluvium in the river valley is stored in these landforms. Sedimentation, however, was interrupted by several periods of landscape stability and soil formation. Radiocarbon ages from the upper A horizons of buried soils in the T-1 and AF-1 fills, indicating approximate burial ages, cluster at ca. 6500, 4500, 3500, and 1000 yr B.P. Also, based on the radiocarbon ages, the T-0c fill and AF-0c fans were aggrading between ca. 2000–900 yr B.P. Given that the T-0c fill and upper parts of the T-1 fill were both aggrading after ca. 2000 yr B.P., we suggest that the T-1 surface was abandoned between ca. 4500–3500 yr B.P., but subsequent aggradation of both the T-1 and T-0c fills occurred due to large-magnitude flood events during the late Holocene. The δ13C data indicate a shift from ∼40% C4 biomass at ca. 6000 to ∼85% at ca. 4500 yr B.P. We propose a scenario where (1) a reduction in C3 vegetation after 6000 yr B.P. destabilized the uplands, resulting in an increase in sediment supply and aggradation of the T-1 fill and AF-1 fans, and (2) the establishment of C4 vegetation by ca. 4500 yr B.P. stabilized the uplands, resulting in a reduction in sediment supply and subsequent incision and abandonment of the T-1 and most AF-1 surfaces. The proposed timing and nature of landscape and bioclimatic change are consistent with regional records from the central Great Plains.

Tropical Rainforest Dynamics and Palaeoclimate Implications since the late Pleistocene, Nilgiris, India

2018 ◽  
Vol 91 (1) ◽  
pp. 367-382 ◽  
Author(s):  
Priyanka Raja ◽  
Hema Achyuthan ◽  
Anjum Farooqui ◽  
Rengaswamy Ramesh ◽  
Pankaj Kumar ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Little Ice Age ◽  
Forest Cover ◽  
Riparian Forest ◽  
Ice Age ◽  
Monsoonal Precipitation ◽  
Dry Conditions ◽  
In The Beginning ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractA multiproxy study involving sedimentology, palynology, radiocarbon dating, stable isotopes, and geochemistry was carried out on the Parsons Valley Lake deposit, Nilgiris, India, to determine palaeoclimatic fluctuations and their possible impact on vegetation since the late Pleistocene. The 72-cm-deep sediment core that was retrieved reveals five distinct palaeoclimatic phases: (1) Warm and humid conditions with a high lake stand before the last glacial maximum (LGM; ~29,800 cal yr BP), subsequently changing to a relatively cool and dry phase during the LGM. (2) Considerable dry conditions and lower precipitation occurred between ~16,300 and 9500 cal yr BP. During this period, the vegetation shrank and perhaps was confined to moister pockets or was a riparian forest cover. (3) An outbreak in the shift of monsoonal precipitation was witnessed in the beginning of the mid-Holocene, around 8400 cal yr BP, implying alteration in the shift toward warm and humid conditions, resulting in relatively high pollen abundance for evergreen taxa. (4) This phase exhibits a shift to heavier δ13C values around ~1850 cal yr BP, with an emergence of moist deciduous plants pointing to drier conditions. (5) Human activities contributed to the exceedingly high percentage ofAcaciaandPinuspollen during the Little Ice Age.

Climatic Implications of the Late Quaternary Alluvial Record of a Small Drainage Basin in the Central Great Plains

1994 ◽  
Vol 41 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Alan F. Arbogast ◽  
William C. Johnson
Keyword(s):  
Great Plains ◽  
Drainage Basin ◽  
Late Quaternary ◽  
Soil Formation ◽  
River System ◽  
Early Holocene ◽  
The Past ◽  
Kansas River ◽  
Dakota Sandstone ◽  
Sand And Gravel

AbstractFour late-Quaternary alluvial fills and terraces are recognized in Wolf Creek basin, a small (163 km2) drainage in the Kansas River system of the central Great Plains. Two terraces were created during the late Pleistocene: the T-4 is a fill-top terrace underlain by sand and gravel fill (Fill I), and the T-3 is a strath terrace cut on the Cretaceous Dakota Sandstone. Both Fill II (early Holocene) and Fill III (late Holocene) are exposed beneath the T-2, a Holocene fill-top terrace. The T-1 complex, consisting of one cut and three fill-top terraces, is underlain by Fills III and IV. A poorly developed floodplain (T-0) has formed within the past 1000 yr. As valleys in Wolf Creek basin filled during the early Holocene, an interval of soil formation occurred about 6800 yr B.P. Early Holocene fill has been found only in the basin's upper reaches, indicating that extensive erosion during the middle Holocene removed most early-Holocene fill from the middle and lower reaches of the basin. Valley filling between 5000 and 1000 yr B.P. was interrupted by soil formation about 1800, 1500, and 1200 yr B.P. As much as 6 m of entrenchment has occurred in the past 1000 yr. Holocene events in Wolf Creek basin correlate well with those in other localities in the central Great Plains, indicating that widespread changes in climate, along with adjustments driven by complex response, influenced fluvial activity.

scholarly journals Late Pleistocene Age of the Type Temple Lake Moraine, Wind River Range, Wyoming, U.S.A.

2007 ◽  
Vol 41 (3) ◽  
pp. 397-401 ◽  
Author(s):  
Gregory A. Zielinski ◽  
P. Thompson Davis
Keyword(s):  
United States ◽  
Late Pleistocene ◽  
Little Ice Age ◽  
Sediment Cores ◽  
Ice Age ◽  
Western United States ◽  
Organic Detritus ◽  
Wind River Range ◽  
Valley Glacier ◽  
The Temple

ABSTRACT The type Temple Lake moraine lies about 3 km beyond and roughly 120 m lower than the modern glacier margin and the Gannett Peak (Little Ice Age) moraines deposited in the last few centuries. Because numerous glacial deposits throughout the western United States have been correlated to the Temple Lake moraine its age is important. We retrieved two sediment cores up to six meters long from Rapid Lake, outside the outer type Temple Lake moraine. The 383-413 cm depth dates 11,770 ± 710 yrs (GX-11,772), which we believe reflects the time when silt flux into Rapid Lake was abruptly reduced by the formation of a new sediment trap at Miller Lake as the valley glacier receded from its position at the outer Temple Lake moraine. A radiocarbon date of 11,400 ± 630 yrs BP (GX-12,719) obtained from the lower basin of Temple Lake, inside the inner type Temple Lake moraine, supports this interpretation. Sediments from Miller Lake, inside the outer Temple Lake moraine, that date 8300 ± 475 yrs BP (GX-12,277) are probably well above the bottom of the lake sediment sequence and possibly thousands of years younger than the moraine. We feel that the type Temple Lake moraine dates about 12,000 yrs BP, thus is Late Pleistocene in age. This interpretation is supported by maximum percentages of organic detritus in lake sediments between 10,000 and 8,000 yrs BP, and challenges BEGET's (1983) suggestion that the type Temple Lake moraine is early Holocene in age, a period he calls "Mesogiaciation".

scholarly journals Zur Problematik der pleistozänen und holozänen Vergletschernung Süd-Kamtschatkas – erste Ergebnisse bodengeographischer Untersuchungen

1996 ◽  
Vol 46 (1) ◽  
pp. 132-143
Author(s):  
Wolfgang Zech ◽  
Rupert Bäumler ◽  
Oskana Savoskul ◽  
Gerlinde Sauer
Keyword(s):  
Late Pleistocene ◽  
Soil Formation ◽  
Ice Age ◽  
Second Phase ◽  
Pleistocene Glaciation ◽  
Middle Europe ◽  
Tephra Layers ◽  
Erste Ergebnisse ◽  
Early Late ◽  
Glacial Advance

Abstract. In the Plotnikova Valley, west of Petropavlovsk in South Kamchatka, two valley drift complexes can be identified. They are correlated with glaciofluvial terraces. The older, so called M1-moraines descend to about 300 m a.s.l. corresponding with the T1-terraces; they are smoothand vague-shaped, without kettles. The younger, so called M2-moraines descend to 350-450 m a.s.l.; their relief is well formed and rich in kettles and ridges, and they are connected with the T2-terraces. The soils developed on these drifts and terraces do not differ significantly with respect to colour and weathering intensity. Soils of the older drift and terraces reveal stronger cryogenetic disturbances and their boulders and gravels are characterized by more pronounced weathering crusts in comparison to the younger drift and terraces. No features indicating interglacial weathering can be identified in the subsoils. But all soils are stratified by 3-4 tephra layers, due to the following eruptions: tephra 1 = Opala, 1400-1500 a BP; tephra 2 = Ksudach 1, 1700-1800 a BP; tephra 3 = Ksudach 2 = 6000 a BP; tephra 4 = Kuril Lake Il'inskay, 7600-7700 a BP (BRAITSEVA et al. 1992). According to these results it is supposed that both moraines indicate Late Pleistocene glaciation; the M1 drift was deposited during an early phase of the Late Pleistocene, the M2 drift characterizes a second phase of the Late Pleistocene, separated only by an interstadial, not by an interglacial. In contrast to Middle Europe, early Late Pleistocene glaciation has been more pronounced than Late Pleistocene second phase glaciation. Studying soil development on frontal moraines along a sequence from 350 to 1000 m a.s.l. in the Topolovaya-Valley it was found that up to about 930 m a.s.l. all soils are stratified by tephra 1-4 layers, indicating that the age of the corresponding moraines is older than 7600/7700 a BP. Drift in about 980 m a.s.l. shows only tephra 1 and 2. These moraines are older than 1700/1800 a BP, but younger than 6000 a BP. Probably they indicate a glacial advance during the middle Holocene (Neoglacial). In 1000 m a.s.l. two additional ridges can be identified, well formed with initial soil formation but without tephra. According to the lichenometric results they characterize snow and ice accumulations during the so-called "Little Ice Age".

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