USGS Science⌕ Search
Home/Archive/USGS

USGS · 70000127

Loess record of the Pleistocene-Holocene transition on the northern and central Great Plains, USA

J.A. Mason·X. Miao·P.R. Hanson·W.C. Johnson·P.M. Jacobs·R.J. Goble
View original source ↗Export metadata ↓

Abstract

Various lines of evidence support conflicting interpretations of the timing, abruptness, and nature of climate change in the Great Plains during the Pleistocene-Holocene transition. Loess deposits and paleosols on both the central and northern Great Plains provide a valuable record that can help address these issues. A synthesis of new and previously reported optical and radiocarbon ages indicates that the Brady Soil, which marks the boundary between late Pleistocene Peoria Loess and Holocene Bignell Loess, began forming after a reduction in the rate of Peoria Loess accumulation that most likely occurred between 13.5 and 15 cal ka. Brady Soil formation spanned all or part of the B??lling-Aller??d episode (approximately 14.7-12.9 cal ka) and all of the Younger Dryas episode (12.9-11.5 cal ka) and extended at least 1000 years beyond the end of the Younger Dryas. The Brady Soil was buried by Bignell Loess sedimentation beginning around 10.5-9 cal ka, and continuing episodically through the Holocene. Evidence for a brief increase in loess influx during the Younger Dryas is noteworthy but very limited. Most late Quaternary loess accumulation in the central Great Plains was nonglacigenic and was under relatively direct climatic control. Thus, Brady Soil formation records climatic conditions that minimized eolian activity and allowed effective pedogenesis, probably through relatively high effective moisture. Optical dating of loess in North Dakota supports correlation of the Leonard Paleosol on the northern Great Plains with the Brady Soil. Thick loess in North Dakota was primarily derived from the Missouri River floodplain; thus, its stratigraphy may in part reflect glacial influence on the Missouri River. Nonetheless, the persistence of minimal loess accumulation and soil formation until 10 cal ka at our North Dakota study site is best explained by a prolonged interval of high effective moisture correlative with the conditions that favored Brady Soil formation. Burial of both the Brady Soil and the Leonard Paleosol by renewed loess influx probably represents eolian system response that occurred when gradual change toward a drier climate eventually crossed the threshold for eolian activity. Overall, the loess-paleosol sequences of the central and northern Great Plains record a broad peak of high effective moisture across the late Pleistocene to Holocene boundary, rather than well-defined climatic episodes corresponding to the B??lling-Aller??d and Younger Dryas episodes in the North Atlantic region. ?? 2008 Elsevier Ltd. All rights reserved.

Explore related subjects

Quaternary Science ReviewsArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J.A. Mason, X. Miao, P.R. Hanson, W.C. Johnson, P.M. Jacobs, R.J. Goble. 2008. Loess record of the Pleistocene-Holocene transition on the northern and central Great Plains, USA. https://doi.org/10.1016/j.quascirev.2008.07.004

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

A 30,000-year continuous record of glacial history and water balance from Fish Lake, Utah documents the onset, development, and demise of LGM glaciation

Fish Lake provides a continuous, high-resolution freshwater paleoclimate archive of glacial and hydroclimate history from a catchment straddling the Colorado Plateau–Great Basin boundary in the western US. At >3600 m, the Fish Lake Plateau glaciates during stadials, making it an ideal site for tracking the region's glacial history. The high-resolution (>3.3 mm/decade) record contains multiple climate- and ecosystem-sensitive proxies. Geochronology relies on 210 Pb and AMS 14 C measurements on terrestrial macrofossils and charcoal, tephrochronology, and paleomagnetic measurements. Multiproxy analyses include indicators of glacial erosion (magnetic susceptibility, sediment density, % mineral matter, grainsize, scanning XRF) and biological productivity (biogenic silica, organic matter). These proxies show glacial inception during the local Last Glacial Maximum at 25.8 ka, coincident with Heinrich Stadial 2, with maximum down-valley ice expansion between 24.8 and 20.9 ka. Glaciers reached the shoreline but did not override the lake, and sedimentation rates did not exceed Holocene levels, as increased glacial erosion was offset by reduced productivity in the glaciated, turbid lake. Deglaciation began by 18.2 ka, was interrupted by a readvance under wetter conditions synchronous with Heinrich Stadial 1 and concluded with final catchment deglaciation ∼14.1 ka. After 13.7 ka, productivity proxies rise rapidly and remain high through the Holocene while erosion proxies drop abruptly. Comparison with the adjacent Bonneville pluvial lake-level record shows that glacial onset on the Fish Lake Plateau preceded the rise in Bonneville water levels at ∼24 ka by roughly a millennium, implying temperature decreases led P-E increases. Similarly, deglaciation onset preceded falling Bonneville water levels by several centuries.

Utah↗
USGS2026

Sedimentological reconstruction of hurricane storm surges from a carbonate reef coastline at Anegada, British Virgin Islands

Anegada is a small, low-lying carbonate island in the British Virgin Islands that is highly vulnerable to marine inundation from frequent hurricanes. A major challenge in forecasting the timing, intensity, and impacts of future hurricanes to islands such as Anegada is the limited short-term instrumental record that does not capture the full spectrum of inundation events from the frequent but low-magnitude to rare, but high-magnitude events. Washover deposits, which are transported onshore by hurricane-related storm surges and preserved within the onshore stratigraphy, can provide insight into the recurrence of these events. Here, we use grain size distributions, X-ray fluorescence (XRF) data, and an inverse sediment transport model to characterize a series of anomalous sand deposits from shallow hypersaline ponds to determine the variability in storm surges impacting Anegada over at least the last 70 years. The analyses were successfully applied to modern analogues of storms impacting Anegada's southern shoreline (Hurricanes Donna in 1960 at Category 3; Earl in 2010 at Category 4; and Irma in 2017 at Category 5). These deposits are identified by coarse-grained material and elevated marine geochemical signals (Ca, Sr, ln(Br/Ti)). Inverse modelled flow parameters (average flow depth = 0.89–1.46 m relative to the reef flat, average flow speed = 2.95–3.78 m/s) agree with observational data and eyewitness accounts, and the deposit associated with Hurricane Donna indicates the greatest impacts occurred along the southern shoreline (modelled flow depth = 1.24–1.46 m relative to the reef flat, flow speed = 3.49–3.78 m/s). Using the modern analogues as a basis for comparison, we infer the origin of an older sand deposit to be from Hurricane Dog in 1950, when it tracked by Anegada as a Category 3 storm. This methodology provides a transferable framework for interpreting storm recurrence in carbonate-dominated coastlines worldwide that could be used to inform hurricane hazard assessments and risk management efforts.

Anegada↗
USGS2026

Temperature and precipitation source variability and glacial dynamics in the southwestern United States at Fish Lake, Utah, since late MIS 4

An improved understanding of hydroclimate response to natural climate forcings is needed to evaluate impacts of changing seasonal circulation patterns on current and future drought in the southwestern United States (‘the Southwest’). However, few terrestrial records from the Southwest preserve changes in moisture availability continuously prior to the Last Glacial Maximum (LGM, ∼24.5 ka). Fish Lake, in the Upper Colorado River Basin, preserves a long (∼67 ka), continuous, high-resolution (∼3.3 cm/century) sedimentary record spanning from late Marine Isotope Stage (MIS) 4 to present. Here, we investigate the relative contributions of seasonal precipitation and moisture source using the hydrogen isotope value of the n -C 29 leaf wax alkane and changes in temperature using branched glycerol dialkyl glycerol tetraethers (brGDGTs). During the warm post glacial period (14 ka to present), a greater contribution of annual precipitation is sourced from the North American Monsoon (NAM) in response to declining winter insolation and rising greenhouse gases, weakening westerly storms and shifting them northward. MIS 3 (∼61 to 29 ka) is also influenced by NAM inputs, however, to a smaller magnitude than during the post glacial period when temperatures were warmer. However, stadial periods (MIS 2, 29 to 14.1 ka) show 2 H-enriched values, suggesting warm conditions and large contributions of NAM precipitation during the LGM, contradicting other proxies and regional records. The LGM is the only period in the record where glaciers are present in the catchment, thus we hypothesize glacial erosion reworked pre-LGM aged soil organic matter and biased the record during this time.

Utah↗