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Muhs, Daniel R.; Aleinikoff, John N.; Stafford, Thomas W.; Kihl, Rolf; Been, J.M.; Mahan, Shannon A.; Cowherd, Scott D.

doi:10.1130/0016-7606(1999)111<1861:lqlinc>2.3.co;2

Cited by 123 publications

(5 citation statements)

References 64 publications

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“…Muhs et al (1999a) documented spatial variation in the geochemistry and mineralogy of eolian sands across the Sand Hills, but we have not identified temporal changes in sand composition allowing differentiation of Pleistocene and Holocene deposits without OSL dating. Our cores seldom contained paleosols or other potential stratigraphic markers, probably because of frequent erosional truncation, and efforts to use ground-penetrating radar to characterize the stratigraphy within the large dunes have been unsuccessful so far.…”

Section: Geomorphological Interpretation Of the Osl Agesmentioning

confidence: 89%

Late Pleistocene dune activity in the central Great Plains, USA

Mason

Swinehart

Hanson

et al. 2011

Quaternary Science Reviews

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Section: Geomorphological Interpretation Of the Osl Agesmentioning

confidence: 89%

Late Pleistocene dune activity in the central Great Plains, USA

Mason

Swinehart

Hanson

et al. 2011

Quaternary Science Reviews

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“…One possible way to identify local effects on PSD is to compare the spatial patterns of loess thickness and PSD over a depositional area (e.g., Muhs et al, 1999Muhs et al, , 2008Mason, 2001;Mason et al, 2003) as the trends may provide insights into sediment transport pathways or distance from the source, availability of sediment, and sedimentation rate. Furthermore, these comparisons allow wider patterns to be identified that are independent of local topographic or proximal source influences.…”

Section: Comparison With Other Northern Iranian and Global Loess Recordsmentioning

confidence: 99%

Late Pleistocene Climate and Dust Source From the Mobarakabad Loess–Paleosol Sequence, Northern Foothills of the Alborz Mountains, Northern Iran

et al. 2021

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Paleoclimatic investigation of loess-paleosol sequences from northern Iran is important for understanding past changes in a region highly sensitive to shifts in precipitation, and along potential routes of past human migration. Here, we present carbon and oxygen isotopic compositions of bulk carbonate (δ13Cbc and δ18Obc, respectively) coupled with particle size distributions of samples from the Mobarakabad section, northern Iran, to study past wind dynamics and hydroclimate. We also present new initial clay-sized Hf-Nd isotope results from key horizons in order to assess general dust sources. Variations of δ13Cbc and δ18Obc values of modern soils compared to paleosols allow reconstruction of late Pleistocene–Holocene climate change in the area. Our results show severe drought during a major eolian deposition phase (EDP) after 34 ka. The thickness and PSD of the C horizon of unit 5 suggest significant shifts in loess sources and depositional environments during this EDP after 34 ka. Indeed, based on our new clay-sized Hf-Nd data, we hypothesize that the loess unit 5 might originate from the young crustal source of the Alborz and Kopet Dagh mountains. In general, the PSD of C horizons in the section is bimodal in the silt fraction and the very small, very fine clay fraction, with a mode at c. 1 μm in the modern soil and paleosols possibly produced by weathering and pedogenic processes. There also appears to be a good correlation between δ13Cbc and δ18Obc values, differentiating phases of loess accumulation and paleosol formation and hence providing quantitative data for reconstructing paleoclimatic conditions in the study area.

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“…The remaining offset between modern and late-glacial shell δ 13 C values is most likely due to differences in the δ 13 C values of the snail diet. Generally, modern tundra, boreal forest, and coastal forest biomes in Alaska are all dominated by C 3 plants (average δ 13 C value of −26‰), which include trees and coolseason grasses and are depleted in 13 C compared with C 4 plants (average δ 13 C value of −12‰) (O 'Leary, 1988;Muhs et al, 1999Muhs et al, , 2000. C 3 and C 4 plants fractionate carbon isotopes in different ways.…”

Section: Paleo-vegetation Inferencesmentioning

confidence: 99%

“…when atmospheric CO 2 concentrations were much lower than during interglacial times (Sigman and Boyle, 2000). However, it is likely that regional temperatures override this factor, with lower last glacial temperatures being more important than CO 2 in determining the relative abundance of C 3 and C 4 plants, as seen in Muhs et al (1999).…”

Section: Paleo-vegetation Inferencesmentioning

confidence: 99%

Late glacial–Younger Dryas climate in interior Alaska as inferred from the isotope values of land snail shells

Nield,

Yanes,

Reuther

et al. 2023

Quat. res.

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The isotope values of fossil snail shells can be important archives of climate. Here, we present the first carbon (δ13C) and oxygen (δ18O) isotope values of snail shells in interior Alaska to explore changes in vegetation and humidity through the late-glacial period. Snail shell δ13C values were relatively consistent through the late glacial. However, late-glacial shell δ13C values are 2.8‰ higher than those of modern shells. This offset is best explained by the Suess effect and changes in the δ13C values of snail diet. Snail shell δ18O values varied through the late glacial, which can be partially explained by changes in relative humidity (RH). RH during the snail growing period was modeled based on a published flux balance model. Results suggest a dry period toward the beginning of the Bølling–Allerød (~14 ka) followed by two distinct stages of the Younger Dryas, a wetter stage in the early Younger Dryas from 12.9 to 12.3 ka, and subsequent drier stage in the late Younger Dryas between 12.3 and 11.7 ka. The results show that land snail isotopes in high-latitude regions may be used as a supplementary paleoclimate proxy to help clarify complex climate histories, such as those of interior Alaska during the Younger Dryas.

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Cited by 123 publications

References 64 publications

Late Pleistocene dune activity in the central Great Plains, USA

Late Pleistocene dune activity in the central Great Plains, USA

Late Pleistocene Climate and Dust Source From the Mobarakabad Loess–Paleosol Sequence, Northern Foothills of the Alborz Mountains, Northern Iran

Late glacial–Younger Dryas climate in interior Alaska as inferred from the isotope values of land snail shells

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