Climate and vegetation change during the late-glacial/early-Holocene transition inferred from multiple proxy records from Blacktail Pond, Yellowstone National Park, USA

Abstract

A series of environmental changes from late-glacial ice recession through the early Holocene are revealed in a 7000-yr-long record of pollen, charcoal, geochemistry, and stable isotopes from Blacktail Pond, a closed-basin lake in Yellowstone National Park. Prior to 11,500 cal yr BP, cool conditions dominated, fire activity was low, and alpine tundra and Picea parkland grew on the landscape. A step-like climate change to warm summer conditions occurred at 11,500 cal yr BP. In response, fire activity increased facilitating a transition from Picea parkland to closed Pinus forest. From 11,500 to 8280 cal yr BP, warm summers and abundant moisture mostly likely from high winter snowfall supported closed Pinus contorta forests. Cooler drier summer conditions prevailed beginning 8280 cal yr BP due to decreased summer insolation and winter snowpack, and lower parkland developed. The timing of vegetation change in the Blacktail Pond record is similar to other low- and middle-elevation sites in the northern Rocky Mountains during the late-glacial period, suggesting local plant communities responded to regional-scale climate change; however, the timing of vegetation changes was spatially variable during the early and middle Holocene due to the varying influences of strengthened summer monsoons and subtropical high on regional precipitation patterns.

Patterns of terrestrial and limnologic development in the northern Greater Yellowstone Ecosystem (USA) during the late-glacial/early-Holocene transition

“…For example, mesophytic closed subalpine forests grew at Crevice Lake and Blacktail Pond until 8200 cal yr BP Krause and Whitlock, 2013), and Pinus-Juniperus forest was present at Slough Creek Pond prior to 8000 cal yr BP (Millspaugh et al, 2004). In addition, charcoal data from the three sites indicate low fire-episode frequency during the early Holocene.…”

“…Following deglaciation, sparsely vegetated landscapes transitioned to Picea parkland at 13,300 cal yr BP near Dailey Lake, 12,900 cal yr BP near Blacktail Pond (Krause and Whitlock, 2013), and later at Slough Creek Pond beginning 12,500 cal yr BP (Millspaugh et al, 2004;Krause, unpublished data). As growing season temperatures increased, closed subalpine forests developed on the upper slopes near Dailey Lake at 12,300 cal yr BP and then later near Blacktail and Slough Creek ponds at 11,300 cal yr BP.…”

“…95°N, 110.60°W, elev. 2012 m;Huerta et al, 2009;Krause and Whitlock, 2013); Crevice Lake (45.00°N, 110.58°W, elev. 1684 m; Whitlock et al, 2012);and Slough Creek Pond (44.92°N, 110.35°W, elev.…”

Lake core record of Grinnell Glacier dynamics during the latest Pleistocene deglaciation and the Younger Dryas, Glacier National Park, Montana, USA

“…Exposure-age chronologies from the Yellowstone Plateau indicate that glaciers had reached their LGM positions between 19 and 15 ka (Licciardi and Pierce, 2008) and evidence from a lake core in Glacier National Park, Montana (GNP) suggest that the major glacial retreat during the post-LGM deglaciation had occurred by 14 ka (Carrara, 1995). In addition, lacustrine records in the region show a distinct change from cool and dry vegetative conditions beforẽ 17 ka to warmer and wetter vegetative conditions by~11.5-10.5 ka (Whitlock, 1993;Mumma et al, 2012;Krause and Whitlock, 2013). Vegetation records from the northern Rockies do not characterize the YD cold interval as a full vegetation reversal; however, some records indicate a prolonged cool period following deglaciation and lasting until~11.5 ka (Krause and Whitlock, 2013).…”

“…In addition, lacustrine records in the region show a distinct change from cool and dry vegetative conditions beforẽ 17 ka to warmer and wetter vegetative conditions by~11.5-10.5 ka (Whitlock, 1993;Mumma et al, 2012;Krause and Whitlock, 2013). Vegetation records from the northern Rockies do not characterize the YD cold interval as a full vegetation reversal; however, some records indicate a prolonged cool period following deglaciation and lasting until~11.5 ka (Krause and Whitlock, 2013). Although the dates of glacier maximum positions are well constrained in the northern U.S. Rockies, precise timing of the advance and retreat of these glaciers is not well understood and has been shown to be spatially variable (Licciardi et al, 2004;Thackray, 2008).…”