Abrupt Climate Oscillations During the Last Deglaciation in Central North America

Abstract

Evidence from stable isotopes and a variety of proxies from two Ontario lakes demonstrate that many of the late glacial–to–early Holocene events that are well known from the North Atlantic seaboard, such as the Gerzensee-Killarney Oscillation (also known as the Intra-Allerød Cold Period), Younger Dryas, and Preboreal Oscillation, also occurred in central North America. These results thus imply that climatic forcing acted in the same manner in both regions and that atmospheric circulation played an important role in the propagation of these events.

Charcoal in soils of the Allerød-Younger Dryas transition were the result of natural fires and not necessarily the effect of an extra-terrestrial impact

“…The rapid climatic shifts during the so-called Lateglacial period (ca 12,500 -10,150 radiocarbon yr BP) were first discovered, and have been most intensively studied, in the northern hemisphere, especially in northwestern Europe (Iversen, 1947;van der Hammen, 1951;van Geel et al, 1989;Bohncke, 1993;Björck et al, 1998;Yu & Eicher, 1998;Walker et al, 2001;Lowe et al, 2008;Steffensen et al, 2008;Hoek, 1997Hoek, , 2008Brauer et al, 2008). According to van der Hammen (1951, p. 120) forest fires occurred after the shift from relatively warm interstadial climatic conditions to much colder conditions at the Allerød-Younger Dryas transition:…”

Fire history on the California Channel Islands spanning human arrival in the Americas

“…Understanding the impact of the human vanguard into North America is further complicated by the contemporaneous changes in climate during the LGIT [58][59][60][61][62]. In particular, the Younger Dryas cold event (ca 12.9 ka BP) [63][64][65][66] contributed to rapid environmental shifts at a key time during human arrival in, and/or migration through, the Americas.…”

The Saint-Narcisse morainic complex and early Younger Dryas events on the southeastern margin of the Laurentide Ice Sheet

“…In the Lake Erie area and other parts of the Great Lakes, Lewis and Anderson (1992) recognized a cool period from about 11 000 to 10 500 BP. West of Lake Ontario, multi-proxy data suggests that the mean annual air temperature began to drop quickly just prior to 11 000 BP, eventually reaching 3°C below pre-YD temperature at 10 500 BP (Yu and Eicher, 1998). The cold event is also recorded in lakes from northern Maine (Dorion, 1998(Dorion, , 2002, where the onset of a YD lithozone is dated at 10 720 ± 60 and 10 650 ± 80 BP from insect parts and terrestrial plant debris.…”

“…The duration of the YD chron is about 900 14 C yr, between 10 900 and 10 000 BP, and about 1300-1400 sideral years between 12.94-12.7 cal ka and 11.64-11.4 cal ka (Mangerud and Gulliksen, 1975;Mangerud et al, 1974Mangerud et al, , 1979Mangerud, 1987;Broecker, 1992;Alley et al, 1993;Bond et al, 1993;Grootes et al, 1993;Bard et al, 1994;Björck et al, 1996;Gulliksen et al, 1998;Yu and Eicher, 1998).…”