Neoglacial chronology and floristics in the Middle Teton area, central Teton Range, Western Wyoming

Abstract

The relative ages of Neoglacial deposits above 2900m near Cloudveil Dome, Middle Teton, and Teepe glaciers, central Teton Range, western Wyoming, were determined using topographic position, weathering features, lichenometry, vegetation characteristics, and soils. A three-fold deposit sequence is identified and correlated with the Gannett Peak, Audubon and Indian Basin Neoglacial advances described elsewhere in the Teton and nearby Wind River ranges. While soil profile morphology proved very useful in distinguishing deposits of different age, other age indicators such as clay mineralogy and soil chemistry, proved of only marginal value in age discrimination. This chronosequence, emplaced over the last -5000yr, provides an excellent setting upon which to test changes in plant species composition and its use as a relative dating method.Vascular plant species composition cannot be used to discriminate deposits of the different advances, possibly because of random colonisation and establishment combined with extensive mass wasting during the Neoglacial. However, certain vegetation features, such as total cover and species densities, appear useful as relative dating methods. Journal of QuaterGry Science

Late glacial retreat and Neoglacial advance sequences in the Zillertal Alps, Austria

“…Further, assuming 200 mm is the largest lichen in the foreland it would appear the longevity for Rhizocarpon, based on 60 mm great growth plus 10 mm/century would be 1400 years. Values for diameters of Lecanora and Lecidea bear similarities to measurements undertaken elsewhere with the exception that Lecanora exhibits measurable thalli within the LIA while in other more continental areas this genus is not recognizable on substrates within the first few hundred years (Mahaney, 1978;Mahaney and Spence, 1990). Soil morphogenesis on deposits of Late Pleistocene and Late Neoglacial (LIA) age is remarkable mainly because of rapid development in early stages of the LIA.…”

Natural and historical variability in fluvial processes, beaver activity, and climate in the Greater Yellowstone Ecosystem

“…Although the prevalence of beaver‐pond deposits dating within the last 4200 years is at least partly an artifact of better preservation and exposure of younger sediments, it may also reflect an increase in beaver activity with the onset of generally cooler, wetter conditions of the late Holocene Neoglacial period. This climatic change is indicated by expansion of glaciers in GTNP (Mahaney and Spence, ) and the Rocky Mountain region in general (Luckman et al ., ), along with an increase in spruce, fir, and pine in the southern GYE (Whitlock and Bartlein, ) and episodes of extensive lateral migration of stream channels in northern YNP (Meyer et al ., ). During the Neoglacial, increased discharges and fewer ephemeral flows would have favored beaver populations in small GYE streams (Wolff et al ., ).…”

Slope Failures and Cross-Valley Profiles, Grand Teton National Park, Wyoming

“…Modern textbooks describe the cross-valley profile of deglaciated terrain as U-shaped (Christopherson, 2009;Plummer, et al, 2010;Love, et al, 2007), however connotations of the forms have been debated for approximately a century. According to several authors, Davis (1916) was the first to suggest that deglaciated cross-valley profiles are catenaries, which are the curves produced when a flexible, but non-stretchable cord, hangs freely from two points (Graf, 1970;Hirano & Aniya, 1988, 1989, 1990). This notion was followed by the work of Svensson (1959), who was the first to describe deglaciated cross-valley profiles as parabolas using the equation Y = aX b , where Y is valley height, X is valley width, and a and b are coefficients (Graf, 1970;Hirano & Aniya, 1990).…”

“…Harbor et al (1988) and Harbor (1992Harbor ( , 1995 were concerned with mathematical modeling of deglaciated cross-valley profiles through time, and found that the a key factor was the increased erosion at the thalweg of glacial channels, a result of -weaker‖ rocks and higher basal ice velocity in the thalwegs of glacial valleys than at the margins. Augustinus (1992Augustinus ( , 1995 postulated that cross-profile morphology in the Southern Alps of New Zealand is a -direct consequence of the rock mass strength properties of the slope rock.‖ (Augustinus, 1992, p 39) Hirano and Aniya (1988, 1989, 1990) investigated the differences between alpine and continental glaciations based on cross-profile morphologies (curve analyses) from other studies (including Graf 1970), and concluded that alpine glaciations are prone to overdeepening, while continental glaciations produce considerably wider subglacial valleys with different form ratios. Seppala (1978) investigated faulting and rock jointing as paramount variables in cross-valley profiles for the Lemon Creek and Ptarmigan glaciers in the Juneau Ice Field of southeastern Alaska.…”

“…The climate of GTNP at present is considered to be continental and highly variable (Vankat, 1979), having cool summers (such as nearfreezing morning temperatures in July) and cold winters that are typically the lowest temperatures in the U.S., excepting parts of Alaska. According to Mahaney (1990), mean annual temperature for mountain basins is -4ºC, and mean annual minimum and maximum temperatures are -12ºC and 3ºC, respectively. Precipitation in the Rocky Mountains is also quite variable (40-150 cm), according to Vankat (1979), however, Foster et al (2010 modeled precipitation using 30 year weather station records and found that precipitation can reach over 200 cm at the highest elevations in the range.…”