Deglaciation and postglacial treeline fluctuation in the northern San Juan Mountains, Colorado

Carrara, Paul E.

doi:10.3133/pp1782

Cited by 15 publications

(20 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Evidence for low winter:summer precipitation ratios (Fig. 8) (Anderson, 2011) and high summer temperatures (Carrara, 2011;Shuman, 2012) would be consistent with a regime of convective summer precipitation driven by higher than present summer insolation (Harrison et al, 2003). Low snowpack may explain why UBC was not as consistently high and overflowing as in the past 1800 yr (Fig.…”

Section: Implications For Streamflow and Paleoclimatesmentioning

confidence: 67%

Hydrologic changes in Colorado during the mid-Holocene and Younger Dryas

2015

View full text Add to dashboard Cite

The stratigraphy of Upper Big Creek Lake (UBC), an overflowing lake in northern Colorado, indicates that the lake responded to a series of hydroclimatic changes over the past ~ 13,000 years. Modern sediments in eight comparator lakes from across Wyoming and Colorado facilitate the stratigraphic interpretation by showing that littoral sediments have exponentially higher sand content, lower loss-on-ignition (LOI), and lower net accumulation rates than off-shore sediments. Sand layers in two near-shore cores from UBC share the characteristics of the modern littoral sediments (> 80% sand, < 5% LOI, and < 10 cm/ka accumulation rates), and indicate that UBC was > 1.9 m below its outlet from 12,500 to 11,300 and from 7500 to 2100 cal yr BP. Ground-penetrating radar (GPR) profiles consistent with the low-water episodes show correlative sand layers and submerged wave-cut scarps around the lake margin. The stratigraphic features correlate with those formed in the comparator lakes during extensive droughts at > 11,300, 6900–6000, and 4800–3400 cal yr BP as well as a series of north-south anti-phased droughts between 5800 and 1200 cal yr BP. Lake closure at UBC amplified the local changes, and demonstrates that climate changes can increase the extent of intermittent streamflow in the Rocky Mountains relative to today.

show abstract

Section: Implications For Streamflow and Paleoclimatesmentioning

confidence: 67%

Hydrologic changes in Colorado during the mid-Holocene and Younger Dryas

2015

View full text Add to dashboard Cite

show abstract

“…This elevation puts it above the higher early and middle Holocene tree lines described by Carrara (2011) and Benedict (2011). The wooden artifact fragment recovered at this location (24CB2174.1) is of uncertain function, but given the complete absence of other wood at this ice patch, it is almost certainly a manuport.…”

Section: Cb2174mentioning

confidence: 67%

“…Their demise may have followed the end of the Holocene thermal maximum (e.g., Clague and Mathewes, 1989), when the niche in which they were living became less habitable. Carrara's (2011) work with tree remains recovered from a tarn in the northern San Juan Mountains of Colorado and Benedict's (2011) work with the remains of ectomycorrhizal sclerotia in the tundra uplands of the Colorado Front Range suggest that between 10 400 and 6200 cal BP, the tree line in the Rocky Mountains was approximately 80 m to 150 m (150 feet to 500 feet) higher than at present. Both of the tree stumps at 24CB2047 are extremely weathered, consistent with Decay Class 5 (bark absent, log sapwood layers heavily flaked and easy to remove, log circumference flattened) or Class 6 (little structural integrity from outside to inside of log, but wood still present) as established by Brown et al (1998).…”

Section: Cb2047mentioning

confidence: 99%

Withering Snow and Ice in the Mid-latitudes: A New Archaeological and Paleobiological Record for the Rocky Mountain Region

Lee¹

2012

ARCTIC

View full text Add to dashboard Cite

ABSTRACT. In the mid-latitude mountains of North America, archaeological materials have been identified in association with kinetically stable "ice patches" that attracted animals and their human predators. The stable ice in these features exhibits little internal deformation or movement and can preserve otherwise perishable materials for millennia. Eight prehistoric sites have been identified in association with perennial ice patches within the Greater Yellowstone Area of Montana and Wyoming. Surveys in Colorado have produced paleobiological samples, but no definitive archaeological sites. Archaeological remains include ancient wooden dart shafts and fragments, wooden artifacts of unknown function, a wrapped leather object of unknown function, butchered animal remains, and chipped stone artifacts. Fragments of weapons ranging in age from 200 to 10 400 years suggest long-term continuity in ice patch hunting in the region. Paleobiological specimens range in age from several hundred to nearly 8000 years. Bighorn sheep (Ovis canadensis) is a presumed prey species, but the remains of bison (Bison bison) and other large ungulates also occur. Ice patches offer important insights into the use of high-elevation environments by Native Americans. Efforts are ongoing to build and maintain awareness of these resources among federal land managers and the public.Key words: climate change, ice patches, organic artifacts, dart shaft, foreshaft, bighorn sheep, bison, Rocky Mountains RÉSUMÉ. Dans les montagnes de latitude moyenne de l'Amérique du Nord, du matériel archéologique a été repéré dans des « névés » cinétiquement stables où évoluaient certains animaux de même que leurs prédateurs humains. La glace stable de ces névés présente une déformation ou un mouvement interne minime, ce qui permet de préserver des matériaux périssables pendant des milliers d'années. Huit sites préhistoriques ont été répertoriés dans les névés pérennes de la grande région du Yellowstone se trouvant au Montana et au Wyoming. Au Colorado, des levés ont permis de prélever des échantillons paléo-biologiques, mais aucun site archéologique définitif. Parmi les restes archéologiques retrouvés, notons d'anciennes tiges et d'anciens fragments de propulseurs en bois, des artefacts en bois dont la fonction est inconnue, un objet enveloppé en cuir dont la fonction est inconnue, des restes d'animaux dépecés et des artefacts en pierre taillée. Des fragments d'armes âgés de 200 à 10 400 ans laissent entrevoir que la chasse a été pratiquée dans les névés de la région pendant très longtemps. L'âge des spécimens paléobiologiques varie de plusieurs centaines d'années à près de 8 000 ans. Le mouflon d'Amérique (Ovis canadensis) y est une espèce-proie présumée, et des restes de bisons (Bison bison) et d'autres grands ongulés s'y trouvent également. Les névés permettent de mieux comprendre comment les Autochtones utilisaient les milieux en haute altitude. Les responsables fédéraux de la gestion des terres et le public déploient des efforts constants pour sensibiliser le...

show abstract

“…In central Colorado, Holocene temperature trends have not been quantified, but macrofossil remains of tree species indicate that tree lines were higher than today before ca. 6.2 ka both in central Colorado near Emerald Lake (Fall, 1997) and in the San Juan Mountains of southwest Colorado (Carrara et al, 1991;Carrara, 2011); (Fig. 7).…”

Section: Causes Of the Holocene Rise In Water Levelsmentioning

confidence: 94%

“…Gray diamonds indicate the ages of sub-fossil wood that mark an upward shift in alpine tree line in Colorado (Carrara, 2011). content (highest water) in the Lake of the Woods cores at ca. 2.0-1.2 ka (Fig.…”

Section: Figure 7 a Comparison Of A Pollen-inferred Temperatures Fomentioning

confidence: 99%

A north-south moisture dipole at multi-century scales in the Central and Southern Rocky Mountains, U.S.A., during the late Holocene

Shuman¹,

Carter²,

Hougardy³

et al. 2014

Rocky Mountain Geology

View full text Add to dashboard Cite

Lake-level changes since ca. 3.6 kilo-annum (ka) at Emerald Lake in the Upper Arkansas River Basin of west-central Colorado coincide in time with changes of the opposite direction at Lake of the Woods in northwestern Wyoming. The contrast provides evidence of a multi-centennial moisture dipole across the Southern and Central Rocky Mountains' region similar to one associated with the effects of the El Niño Southern Oscillation (ENSO) on annual to decadal time scales today. Cores and ground penetrating radar (GPR) profiles from Emerald Lake show that deep-water muds accumulated as extensively across the lake basin as today at ca. 3.6-3.0 and 1.4-0.8 ka, and nearly as extensively at 2.5-1.9 ka. The extensive muds indicate episodes of high water at Emerald Lake and date to times when Lake of the Woods was low. Nearshore sand layers at Emerald Lake indicate that water levels fell during the intervening centuries, including when bristlecone pine chronologies have documented repeated multi-decadal droughts in the Upper Arkansas River Basin. Water levels were also low, based on the absence of nearshore mud accumulation, before ca. 3.6 ka, and dramatically lower (>2 m in the currently 4.5-m deep lake) before a sharp rise in water levels by ca. 5.7 ka. A basin-wide change in sediment accumulation patterns, consistent with an expansion and deepening of the lake at ca. 5.7 ka, correlates with regional cooling and similar evidence of increased effective moisture at Lake of the Woods and other sites throughout central North America. The step increase in moisture availability may relate to a global-scale reorganization of climatic patterns, which developed as the mid-and high-latitudes cooled in response to a decline in summer insolation.

show abstract

Deglaciation and postglacial treeline fluctuation in the northern San Juan Mountains, Colorado

Cited by 15 publications

References 30 publications

Hydrologic changes in Colorado during the mid-Holocene and Younger Dryas

Hydrologic changes in Colorado during the mid-Holocene and Younger Dryas

Withering Snow and Ice in the Mid-latitudes: A New Archaeological and Paleobiological Record for the Rocky Mountain Region

A north-south moisture dipole at multi-century scales in the Central and Southern Rocky Mountains, U.S.A., during the late Holocene

Contact Info

Product

Resources

About