Temperature and precipitation source variability and glacial dynamics in the southwestern United States at Fish Lake, Utah, since late MIS 4
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Abstract
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-C29 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 2H-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.
Suggested Citation
Vornlocher, J.R., O’Beirne, M.D., DePaoli, A., Werne, J., Marchetti, D.W., Anderson, L., Brunelle, A., Stoner, J.S., Reilly, B., Morris, J.L., Kraklow, V.A., Power, M.J., Hatfield, R., Sinon, H., Finkenbinder, M.S., Peters, W., Ritter, C., Larsen, D., Lasher, E., and Abbott, M., 2026, Temperature and precipitation source variability and glacial dynamics in the southwestern United States at Fish Lake, Utah, since late MIS 4: Quaternary Science Reviews, v. 370, 109919, 18 p., https://doi.org/10.1016/j.quascirev.2026.109919.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Temperature and precipitation source variability and glacial dynamics in the southwestern United States at Fish Lake, Utah, since late MIS 4 |
| Series title | Quaternary Science Reviews |
| DOI | 10.1016/j.quascirev.2026.109919 |
| Volume | 370 |
| Publication Date | March 04, 2026 |
| Year Published | 2026 |
| Language | English |
| Publisher | Elsevier |
| Contributing office(s) | Geosciences and Environmental Change Science Center |
| Description | 109919, 18 p. |
| Country | United States |
| State | Utah |
| Other Geospatial | Fish Lake |