A 15 000-year record of climate change in northern New Mexico, USA, inferred from isotopic and elemental contents of bog sediments

• Published in: Journal of quaternary science 2010-09, Vol.25 (6), p.1001-1007
• Main Authors: Cisneros-Dozal, Luz M., Heikoop, Jeffrey M., Fessenden, Julianna, Anderson, R. Scott, Meyers, Philip A., Allen, Craig D., Hess, Marcey, Larson, Toti, Perkins, George, Rearick, Michael
• Format: Article
• Language: English
• Subjects: Algae; Climate; isotopic analyses; Late Pleistocene; lead; Lead (metal); Productivity; Rocks; Runoff; Sediments; Southwest; Southwest, USA; Transport; USA; Younger Dryas
• ISSN: 0267-8179; 1099-1417; 1099-1417
• DOI: 10.1002/jqs.1387

Elemental (C, N, Pb) and isotopic (δ13C, δ15N) measurements of cored sediment from a small bog in northern New Mexico reveal changes in climate during the Late Pleistocene and Holocene. Abrupt increases in Pb concentration and δ13C values ca. 14 420 cal. YBP indicate significant runoff to the shallow lake that existed at that time. Weathering and transport of local volcanic rocks resulted in the delivery of Pb‐bearing minerals to the basin, while a 13C‐enriched terrestrial vegetation source increased the δ13C values of the sedimentary material. Wet conditions developed over a 300 a period and lasted for a few hundred years. The Younger Dryas period (ca. 12 700–11 500 cal. YBP) caused a reduction in terrestrial productivity reflected in decreasing C/N values, δ15N values consistently greater than 0‰ and low organic content. By contrast, aquatic productivity increased during the second half of this period, evidenced by increasing δ13C values at the time of highest abundance of algae. Dry conditions ca. 8 000–6 000 cal. YBP were characterised by low organic carbon content and high Pb concentrations, the latter suggesting enhanced erosion and aeolian transport of volcanic rock. The range in δ13C, δ15N and C/N values in the sedimentary record fall within the range of modern plants, except during the periods of runoff and drought. The sedimentary record provides evidence of natural climate variability in northern New Mexico, including short‐ (multi‐centennial) and long‐(millennial) term episodes during the Late Pleistocene and Holocene. Copyright © 2010 John Wiley & Sons, Ltd.