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

Abstract

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.

Late Glacial and Holocene record of climatic change in the southern Rocky Mountains from sediments in San Luis Lake, Colorado, USA

“…Magnetic susceptibility, a measure of allochthonous magnetic materials from erosion of the watershed or deposition from a volcanic tephra (Dearing, 1999), is widely used to document changes in the sedimentary inputs to a lake or bog in the region (e.g., Cisneros-Dozal et al, 2010;Jimenez-Moreno et al, 2011). The magnetic susceptibility record from San Luis Lake shares some similar features of variability with the C u data (Fig.…”

Geomorphic and sedimentary responses of the Bull Creek Valley (Southern High Plains, USA) to Pleistocene and Holocene environmental change

“…Polyak et al (2004), who also record these wetter conditions as increased stalagmite growth rates in caves from the southwestern US, attribute this environmental transition to a more southerly jet stream during the LGM in response to cooling in the Northern Hemisphere resulting in increased effective moisture in the southwestern US. Many proxy records from across the southern and central Great Plains and adjacent New Mexico suggest the YD brought about cooler conditions (Armour et al, 2002;Johnson et al, 2003;Polyak et al, 2004;Balakrishnan et al, 2005;Anderson et al, 2008;Mandel, 2008;Meltzer, 2009;Cisneros-Dozal et al, 2010;Holliday et al, 2011;Hall et al, 2012;Fig. 10).…”

“…Loess deposition was widespread on the landscapes of present-day Colorado, Kansas, and Nebraskã 10 ka to 4 ka, while dune activity reached a maximum 7 ka to 5 ka (Forman et al, 2001(Forman et al, , 2008. Peak dry conditions in New Mexico were experienced around 8 ka (Asmeron et al, 2007;Cisneros-Dozal et al, 2010). Aeolian erosion and deposition had become pervasive in New Mexico and Texas by 9 ka (Holliday, 1989a(Holliday, , 1995(Holliday, , 2001.…”

“…The middle Holocene (~6 to 3.5 ka) was a time of widespread aridity and temperatures warmer than present across the Great Plains (Holliday, 1989a;Dorale et al, 1992;Holliday, 1995Holliday, , 2001Wong et al, 2015). A millennia-long drought reached its peak between 6.5 and 4.5 ka in the Southern High Plains (Holliday, 1989a(Holliday, , 1995(Holliday, , 2001), slightly later than in New Mexico (Asmeron et al, 2007;Cisneros-Dozal et al, 2010;Fig. 10).…”

“…speleothem geochemistry from New Mexico (Asmeron et al, 2007), B.) foraminifera from a bay in Texas (Buzas-Stephens et al (2014), C.) speleothem geochemistry from Iowa (Dorale et al, 1992), D.) soil del 13 C data from across the Great Plains of North America (Nordt et al, 2008), E.) C/N ratios from a bog in northern New Mexico (Cisneros-Dozal et al, 2010), and F.) soil del 13 C data from the Bull Creek area (Bement et al, 2014) compared to a summary of the environmental changes recorded in the terraces and their deposits of Bull Creek. YD denotes the Younger Dryas.…”