Weak precipitation δ2H response to large Holocene hydroclimate changes in eastern North America
نویسندگان
چکیده
In eastern North America, annual precipitation increased by >40% over the Holocene, largely in response to melting of Laurentide Ice Sheet. The change substantially raised lake levels and transformed conifer-dominated ecosystems into mesic deciduous forests. δ2H values terrestrially derived leaf-wax n-alkanes can facilitate diagnoses climate dynamics involved reconstructing mean (δ2HMAP). However, competing influences on δ2HMAP mid-latitudes, such as changes moisture sources seasonal distribution precipitation, generate confounding effects. To test sensitivity potential associated with final Holocene phases deglaciation we used 14 fossil-pollen records reconstruct monthly model during Holocene. pollen-inferred 100–200 mm both cold warm seasons, but modeled changed only ∼10‰, because isotopically-heavy summer nearly much cold-season isotopically-light winter precipitation. Three new leaf wax n-C29-alkane (δ2HC29) spanning from Vermont, Pennsylvania, Massachusetts closely follow trends confirm a small decline Because shifts seasonality accurately predict n-alkane records, or pathways appear play minor role regional history despite effects atmospheric circulation. Soil evaporation also did not significantly alter δ2HC29 predicted using pollen-derived reconstructions. results affirm that faithfully detected anticipated isotopic values, important paleoclimate events may always yield strong values.
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ژورنال
عنوان ژورنال: Quaternary Science Reviews
سال: 2023
ISSN: ['1873-457X', '0277-3791']
DOI: https://doi.org/10.1016/j.quascirev.2023.107990