Seismic stratigraphy, sedimentary facies, pollen stratigraphy, diatom-inferred salinity, stable isotope (δ18O and δ13C), and chemical composition (Sr/Ca and Mg/Ca) of authigenic carbonates from Moon Lake cores provide a congruent Holocene record of effective moisture for the eastern Northern Great Plains. Between 11,700 and 9500 14C yr B.P., the climate was cool and moist. A gradual decrease in effective moisture occurred between 9500 and 7100 14C yr B.P. A change at about 7100 14C yr B.P. inaugurated the most arid period during the Holocene. Between 7100 and 4000 14C yr B.P., three arid phases occurred at 6600-6200 14C yr B.P., 5400-5200 14C yr B.P., and 4800-4600 14C yr B.P. Effective moisture generally increased after 4000 14C yr B.P., but periods of low effective moisture occurred between 2900-2800 14C yr B.P. and 1200-800 14C yr B.P. The data also suggest high climatic variability during the last few centuries. Despite the overall congruence, the biological (diatom), sedimentological, isotopic, and chemical proxies were occassionally out of phase. At these times the evaporative process was not the only control of lake-water chemical and isotopic composition.
- Northern Great Plains
- Saline lakes