Weak precipitation δ2H response to large Holocene hydroclimate changes in eastern North America
Stefanescu, I. C., Shuman, B. N., Grigg, L. D., Bailey, A., Stefanova, V., et al. (2023). Weak precipitation δ2H response to large Holocene hydroclimate changes in eastern North America. Quaternary Science Reviews, doi:https://doi.org/10.1016/j.quascirev.2023.107990
| Title | Weak precipitation δ2H response to large Holocene hydroclimate changes in eastern North America |
|---|---|
| Genre | Article |
| Author(s) | I. C. Stefanescu, B. N. Shuman, L. D. Grigg, Adriana Bailey, V. Stefanova, W. W. Oswald |
| Abstract | In eastern North America, annual precipitation increased by >40% over the Holocene, largely in response to melting of the Laurentide Ice Sheet. The change substantially raised lake levels and transformed conifer-dominated ecosystems into mesic deciduous forests. 82H values of terrestrially derived leaf-wax n-alkanes can facilitate diagnoses of the climate dynamics involved by reconstructing 82H values of mean annual precipitation (82HMAP). However, competing influences on 82HMAP values in the mid-latitudes, such as changes in moisture sources and in the seasonal distribution of precipitation, can generate confounding effects. To test 82HMAP sensitivity to potential changes associated with the final Holocene phases of deglaciation in eastern North America, we used 14 fossil-pollen records to reconstruct monthly precipitation changes and to model 82HMAP values during the Holocene. The pollen-inferred precipitation increased by 100e20 0 mm during both cold and warm seasons, but modeled 82HMAP values changed by only-10 parts per thousand, because isotopically-heavy summer precipitation increased by nearly as much as the cold-season isotopically-light winter precipitation. Three new leaf wax n-C29-alkane (82HC29) records span-ning the Holocene from Vermont, Pennsylvania, and Massachusetts closely follow modeled 82HMAP trends and confirm only a small decline in 82HMAP values over the Holocene. Because the shifts in pre-cipitation seasonality accurately predict the n-alkane records, changes in moisture sources or pathways appear to play only a minor role in the regional 82HMAP history despite the effects of deglaciation on atmospheric circulation. Soil evaporation also did not significantly alter 82HC29 values from the values predicted using the pollen-derived reconstructions. The results affirm that 82HC29 values faithfully detected anticipated isotopic changes in 82HMAP values, but that important paleoclimate events may not always yield strong changes in 82HMAP values.(c) 2023 Elsevier Ltd. All rights reserved. |
| Publication Title | Quaternary Science Reviews |
| Publication Date | Mar 1, 2023 |
| Publisher's Version of Record | https://doi.org/10.1016/j.quascirev.2023.107990 |
| OpenSky Citable URL | https://n2t.org/ark:/85065/d7zs31f4 |
| OpenSky Listing | View on OpenSky |
| EOL Affiliations | RAF |