Potential glacial evidence for the younger dryas event in the Cordillera of North and South America

Osborn, Gerald; Clapperton, Chalmers M.; Davis, P. Thompson; Reasoner, Mel A.; Rodbell, Don; Seltzer, Geoffrey O.; Zielinski, Greg

doi:10.1016/0277-3791(95)00064-x

Cited by 42 publications

(30 citation statements)

References 30 publications

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“…In the Colorado Front Range, treeline had been depressed during the Younger Dryas interval (Reasoner and Jodry, 2000) but was recovering by 10 ka BP (Short, 1985). Similarly treeline with lodgepole and whitebark pine, spruce, and fir rose to near present elevations in the central and southern Canadian Rockies at this time (Kearney and Luckman, 1983;Hills et al, 1985;Reasoner and Hickman, 1989;Beaudoin and King, 1990;White and Osborn, 1992;Osborn et al, 1995). Drying and warming in the American Southwest is echoed in the expansion of steppe at the expense of subalpine forest in the Great Basin region primarily of Idaho (Baker, 1976;Cotter et al, 1986), by expansion of steppe into the Okanagan region of British Columbia (Hebda, 1982;Heinrichs et al, 1999Heinrichs et al, , 2001) and by the establishment of an interior forest biome characterized by Douglas fir replacing subalpine forest (Heusser, 1965;Hansen and Easterbrook, 1974;Barnosky, 1981;Cwynar, 1987;McLachlan and Brubaker, 1994).…”

Section: Ka Bpmentioning

confidence: 89%

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Dyke

2007

gpq

113

118

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AbstractBiome maps spanning the interval from the last glacial maximum to modern times are presented. The biome distributions at 18 ka BP were probably as nearly in equilibrium with climate as are the modern distributions, but deglacial biomes were probably in disequilibrium. Ice sheet configuration was a strong control of climate until 7 ka BP. Regional climate trends can be inferred from changing biome distributions, but during periods of disequilibrium, biome distributions under-represent summer warming. Because of summer cooling by 2-4 °C during the Holocene, largely in the last 3-5 ka, middle and certain early Holocene biome distributions and species compositions are reasonable analogues of future equilibrium displacements due to equivalent warming, at least in areas that were long-since deglaciated. Past biome migration rates in response to rapid regional warming during deglaciation were mainly in the range of 100-200 m per year. If these rates pertain in the future, biomes may shift 10-20 km in most regions over the next century. A major impediment to using former Holocene conditions as a guide to future conditions is that warmer Holocene summers were accompanied by colder winters, whereas warmer future summers will be accompanied by warmer winters.

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Section: Ka Bpmentioning

confidence: 89%

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Dyke

2007

gpq

113

118

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“…During the last deglaciation after the full-glacial advance of the Cordilleran Ice Sheet, alpine glaciers Ž readvanced and left numerous moraines Luckman and Osborn, 1979;Davis, 1988;Osborn et al, 1995; . Osborn and Gerloff, 1997; Clark and Gillespie, 1997 .…”

Section: Adõance Of Alpine Glaciersmentioning

confidence: 99%

Response of interior North America to abrupt climate oscillations in the North Atlantic region during the last deglaciation

Wright

2001

Earth-Science Reviews

103

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Several broad-scale climatic oscillations during the last deglaciation are well documented in regions around the North Atlantic Ocean. This paper reviews empirical evidence for these deglacial climatic oscillations from non-coastal North America and discusses implications for testing climatic simulations and for understanding the cause and transmittal mechanisms. Paleoclimatic interpretation of oxygen-isotope records from several small sites in the eastern Great Lakes region indicates a classic deglacial climatic sequence that is comparable with records from Europe and Greenland. The Ž . climatic events as interpreted from Crawford Lake oxygen isotopes include the Bølling-Allerød BOA warming at ; 12,700 14 C BP, a warm BOA at ; 12,500-10,920 14 C BP, an intra-Allerød cold period shortly before 11,000 14 C BP, a Ž .14 14cold Younger Dryas YD climate reversal at 10,920-10,000 C BP, the Holocene warming at 10,000 C BP, a brief Ž .14 14 Ž . Preboreal Oscillation PB at 9650 C BP, and an early-Holocene cold event at 7500 C BP 8200 cal BP . Some of these events were also evident from changes in upland and aquatic vegetation and sediment lithology. The pronounced YD climatic reversal has been documented from pollen records along the ecotones at this time and from glacier readvances in the Great Lakes region. Along the Rocky Mountains from Alberta to Colorado, the YD event is indicated by alpine glacier advance andror shift in timberline vegetation. In Minnesota and upper New York, early-Holocene climatic instability is also suggested by oxygen-isotope records andror varve thickness. The regional variations in evidence for the YD and other events in North America suggest that climatic oscillations may have different expressions in paleo-records, depending on geographic location and characteristics of a particular site. The extent and magnitude of these climatic oscillations across North America suggest that these oscillations are an expression of climatic change that was probably widespread rather than locally induced by a nearby glacier. The location of these sites implies that climatic signals were likely carried over the Northern Hemisphere through the atmosphere, as indicated by general circulation models. We hypothesize that the lack of evidence for a cold YD in interior North America west of the Great Lakes region and east of the Rocky Mountains was caused by the trapping of cold arctic air mass north of the Laurentide ice sheet and by uninterrupted northward expansion of warm Caribbean air; this strongly contrasted climate also produced non-analogous biological assemblages. q

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“…For example, the extent of snowline depression in the tropics has been used as a proxy to determine the amount of temperature change during the last glacial maximum (LGM) (e.g., Klein et al, 1999). Glacial events have also been used to investigate the occurrence of high-resolution climatic events in North and South America such as the Heinrich Events (Lowell et al, 1995;Benson et al, 1996Benson et al, , 1998 and the Younger Dryas (Osborn et al, 1995). All of these investigations of inter-hemispheric climate coupling require tight absolute age control of glacial events.…”

Section: Glaciation and Climate Change In The American Cordilleramentioning

confidence: 99%

“…The Younger Dryas has also been looked at in detail to determine if it was an inter-hemispheric glacial event (e.g., Osborn et al, 1995). The best dated sites in the American cordillera are in the Canadian Rockies and the Ecuadorian Andes.…”

Section: Glaciation and Climate Change In The American Cordilleramentioning

confidence: 99%

Paleoclimate reconstruction along the Pole–Equator–Pole transect of the Americas (PEP 1)

Markgraf

Baumgartner

Bradbury

et al. 2000

Quaternary Science Reviews

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Examples are presented of inter-hemispheric comparison of instrumental climate and paleoclimate proxy records from the Americas for di!erent temporal scales. Despite a certain symmetry of seasonal precipitation patterns along the PEP 1 transect, decadal variability of winter precipitation shows di!erent characteristics in terms of amplitude and frequency in both the last 100 and last 1000 years. Such di!erences in variability are also seen in a comparison of time series of di!erent El Nin o/Southern Oscillation proxy records from North and South America, however, these di!erences do not appear to a!ect the spatial correlation with Paci"c sea surface temperature patterns. Local and regional di!erences in response to climate change are even more pronounced for records with lower temporal resolution, and inter-hemispheric synchroneity may or may not be indicative of the same forcing. This aspect is illustrated in an inter-hemispheric comparison of the last 1000 years of glacier variability, and of the full-and lateglacial lake level history.

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Potential glacial evidence for the younger dryas event in the Cordillera of North and South America

Cited by 42 publications

References 30 publications

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Late Quaternary Vegetation History of Northern North America Based on Pollen, Macrofossil, and Faunal Remains*

Response of interior North America to abrupt climate oscillations in the North Atlantic region during the last deglaciation

Paleoclimate reconstruction along the Pole–Equator–Pole transect of the Americas (PEP 1)

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