Late Quaternary Changes in Lakes, Vegetation, and Climate in the Bonneville Basin Reconstructed from Sediment Cores from Great Salt Lake

摘要: Abstract Sediment cores from Great Salt Lake (GSL) provide the basis for reconstructing changes in lakes, vegetation, and climate last ~ 40 cal ka. Initially, coring site was covered by a shallow saline lake surrounded Artemisia steppe or steppe-tundra under cold dry climate. As Bonneville began to rise (from ~ 30 28 cal ka), Pinus subalpine conifer pollen percentages increased declined, suggesting onset of wetter conditions. oscillated near Stansbury shoreline between ~ 26 ~ 24 cal ka, rose ~ 18 cal ka, then fell Provo shoreline, which it occupied until ~ 15 cal ka. Vegetation changed during this time span, albeit not always with same direction amplitude as lake. The conifers were high ~ 25 21.5 cal ka, indicating cool moist conditions oscillation much toward shoreline. decreased became codominant, drier perhaps colder ~ 21 ~ 15 cal ka, when at its highest levels. declined low level ~ 13 cal ka, while increased, that remained cooler moister than today. During Younger Dryas interval, brief Gilbert episode followed stratified water column. This occurred declining those rising (reflecting increasingly conditions), after very levels (suggesting conditions) period. Since ~ 10.6 cal ka lacustrine have resembled present-day GSL. Pollen spectra period ~ 10.6 7.2 cal ka (for Holocene) desert taxa, generally maximum aridity occurring prior deposition Mazama tephra (~ 7.6 cal ka). After ~ 10.6 cal ka, Juniperus increase ~ 7.2 cal ka juniper woodlands well established on lower mountain slopes. From ~ 7 4 cal ka, fluctuated their mean values entire Holocene. neopluvial (~ 4 2 cal ka) wettest part Holocene, higher taxa older Holocene sediments. ~ 2 cal ka are variable, but indicate return