scholarly journals Checklist and Ecology of the Agaricales, Russulales and Boletales in the alpine zone of the Rocky Mountains (Colorado, Montana, Wyoming) at 3000-4000 m a.s.l.

Sommerfeltia ◽  
2008 ◽  
Vol 31 (1) ◽  
pp. 101-123 ◽  
Author(s):  
C. Cripps ◽  
E. Horak
Keyword(s):  
Rocky Mountains ◽  
Woody Debris ◽  
Rocky Mountain ◽  
Front Range ◽  
San Juan Mountains ◽  
The North ◽  
Alpine Zone ◽  
Number Of Publications ◽  
Taxonomic Groups ◽  
Sawatch Range

Checklist and Ecology of the Agaricales, Russulales and Boletales in the alpine zone of the Rocky Mountains (Colorado, Montana, Wyoming) at 3000-4000 m a.s.l.Previously, the Rocky Mountain alpine zone was a mycological blank spot. There have only been a few scattered records of macrofungi from this region and limited number of publications. This alpine survey covers the Beartooth Plateau in Montana/Wyoming for the North-central Floristic Region (lat 45°N) and the Front Range, San Juan Mountains, Sawatch Range for the Southern Floristic Region in Colorado (lat 36°-38°N), and reports over 165 species in 46 genera and 11 families (ca 1 500 collections). It is estimated that over 75% are known arctic-alpine macromycetes and the remainder are Rocky Mountain species. Of these, we estimate that 2-5% are new to science, 75% are new records for this Rocky Mountain alpine zone, and that over half will be new to Colorado or Montana/Wyoming. Approximately 56% are mycorrhizal species associated with Salix reticulata, S. arctica, S. planifolia, S. glauca, Betula nana = B. glandulosa, Dryas octopetala and Polygonum viviparum. Mycorrhizal species that occur with Betula are rare in the Rockies due to a paucity of this host. The most diverse mycorrhizal family is the Cortinariaceae with over 74 species, primarily of Inocybe and Cortinarius. Saprobic genera associate with a diversity of bryophytes or are terrestrial primarily in grassland; macrofungi on woody debris are rare. A greater diversity occurs in southern mountain ranges which are more diverse in geology and habitat. The southern extent of the Rockies at latitudes of 36-38°N likely includes the southernmost extent of certain Arctic-alpine fungi such as Arrhenia auriscalpium for the Northern hemisphere. Macrofungal fruitings are sparse compared to those in maritime arctic-alpine habitats due to a well-defined continental climate with drying winds, low relative humidity, periodic droughts, fire, strong diurnal temperature fluctuations and high elevations of 3 000-4 000 m. This report helps complete distributions of arctic-alpine fungi, and discusses the ecology of individual taxonomic groups in relation to other Arctic-alpine areas.

scholarly journals Deglaciation of the Colorado Rocky Mountains following the Last Glacial Maximum

2017 ◽  
Vol 43 (2) ◽  
pp. 497 ◽  
Author(s):  
E.M. Leonard ◽  
B.J.B. Laabs ◽  
A.D. Schweinsberg ◽  
C.M. Russell ◽  
J.P. Briner ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Rocky Mountains ◽  
Glacial Maximum ◽  
San Juan ◽  
The South ◽  
Last Glacial ◽  
San Juan Mountains ◽  
The North ◽  
Colorado Rocky Mountains ◽  
Exposure Ages

The availability of almost 180 cosmogenic-radionuclide (CRN) surface-exposure ages from moraine boulders and glacially polished bedrock surfaces makes possible an assessment of the timing and character of the local Last Glacial Maximum (LLGM) and subsequent deglaciation in the Colorado Rocky Mountains. A review of glacial chronologies and numerical modeling results indicates that although glaciers across Colorado responded broadly synchronously, apparent differences in the timing and magnitude of glacier retreat following the LLGM suggest that spatially variable regional forcing, possibly precipitation related, played a role in glacier behavior along with more spatially uniform hemispheric or global forcing. Glaciers in the five ranges examined reached their greatest LLGM extents before ~19.5 ka and abandoned their outermost LLGM moraines between ~23.5 and 19.5 ka. Detailed deglaciation chronologies are available for glaciers in four of the ranges. In the Sawatch Range and Sangre de Cristo Mountains, glaciers were near their LLGM extents at 17-16 ka, before retreating rapidly. In the San Juan Mountains and the Front Range, glaciers may have begun their post-LLGM recession earlier, although early deglaciation is indicated by only a few ages on polished bedrock that potentially contains pre-LLGM CRN inheritance, and thus may be too old. Regardless of the timing of the onset of deglaciation, the equilibrium-line rise associated with deglaciation was earlier and significantly larger in the San Juan Mountains than elsewhere in Colorado. This suggests that the San Juan Mountains, located well to the southwest of the other ranges, may have experienced enhanced precipitation during the LLGM, as did areas farther to the south and west, while LLGM conditions may have been drier in the northern and eastern Colorado ranges. A breakdown in this pattern after the LLGM, with precipitation decreasing in the south and west and increasing in the north and east, may have led to the range-to-range differences evident across Colorado. Deglaciation was nearly complete in all four ranges by 15-13 ka. While some proxy records indicate a later Younger Dryas-age cooling in the Colorado mountains, there is not clear moraine evidence of glacier readvance at that time.

scholarly journals Pleistocene Stratigraphy of the Athabasca River Valley Region, Rocky Mountains, Alberta

2007 ◽  
Vol 49 (3) ◽  
pp. 381-399 ◽  
Author(s):  
Victor M. Levson ◽  
Nathaniel W. Rutter
Keyword(s):  
Debris Flow ◽  
Rocky Mountains ◽  
Late Quaternary ◽  
Rocky Mountain ◽  
River Valley ◽  
Alluvial Fan ◽  
Front Range ◽  
Stratigraphic Sequence ◽  
Athabasca River ◽  
Lithostratigraphic Units

ABSTRACTThe Pleistocene stratigraphy of the central Canadian Rocky Mountains is described from a region where few studies of Late Quaternary deposits have been conducted. Six informal lithostratigraphic units are recognized from newly mapped exposures in Jasper National Park. The oldest deposits are interpreted as paleofan deposits (Unit 1) and they are overlain by glaciofluvial gravels and sands (Unit 2), glaciolacustrine sediments (Unit 3) and by a glacigenic diamicton sequence (Unit 4) that includes basal till, supraglacial deposits and ice-marginal debris flow sediments. Proximal glaciofluvial gravels, debris flow deposits and minor glaciolacustrine sediments (Unit 5) and paragiacial fan deposits and loess (Unit 6) cap the stratigraphic sequence. Limited chronologic control suggests that nonglacial fluvial and alluvial fan sedimentation began prior to 48 ka and continued throughout the Middle Wisconsinan. Braided stream deposits were accumulating in the Athabasca River valley near Jasper townsite about 29 ka. In the Late Wisconsinan, Rocky Mountain and Cordilleran glaciers advanced through the area, initially damming lakes in a number of Front Range tributary valleys. During déglaciation, ice-marginal glaciofluvial activity and paragiacial debris flows dominated sedimentation. Glacial lakes were limited in extent. A radiocarbon date on shells from one small ice-marginal lake indicates that glaciers were well in retreat by about 12 ka. Alpine glaciers in the region were at or near their present limits by 10 ka.

A structural interpretation across part of the northern Rocky Mountains, British Columbia, Canada

1979 ◽  
Vol 16 (6) ◽  
pp. 1228-1241 ◽  
Author(s):  
Robert I. Thompson
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Lateral Displacement ◽  
Rocky Mountain ◽  
Thrust Faults ◽  
Northern Rocky Mountains ◽  
Eastern Margin ◽  
The North ◽  
Structural Style ◽  
Mountain Front

The northern Canadian Rocky Mountains, as exemplified by the Halfway River map-area (94B) in British Columbia, consists of a rugged and mountainous structurally complex Foothills subprovince of large amplitude box and chevron-style folds in rocks of late Paleozoic and Mesozoic age, and a structurally diverse Rocky Mountain subprovince with open folds and apparently inconspicuous thrust faults in upper Precambrian to upper Paleozoic rocks; separating them is a narrow topographically subdued and heavily vegetated 'transition interval' comprising more penetratively folded and faulted shales and thin-bedded carbonate rocks of late Devonian and Mississippian age.Flat thrust faults, with displacements in the order of 10 km, which occur under the eastern margin of the Rocky Mountain subprovince (mountain front) extend across the 'transition interval' and beneath the western margin of the Foothills subprovince. These faults terminate within a décollement along the Devonian and Mississippian Besa River shale, as the displacement on them is transformed into disharmonic kink-type box and chevron folds in overlying units and into tectonic thickening within the Besa River shale. Because most of the major thrust faults along the Rocky Mountains are 'blind' and cannot be traced to surface exposures, one is left with the erroneous impression that very little lateral displacement (foreshortening) has occurred in the northern Canadian Rocky Mountains.The basic change from a well organized thrust-fault terrane in the southern Rockies to a more diverse fold terrane with few large mappable thrusts in the north is consistent with changes in the stratigraphic character of the rock prism that was deformed: the proportion of thick incompetent shale units increases northward, and major lateral carbonate to shale facies transitions traverse the eastern margin of the Rocky Mountain subprovince.Despite the differences in structural style from south to north, strain patterns within the northern Rocky Mountains are consistent with the lateral eastward movement of a detached prism of sedimentary rocks, and support the basic tenets of thin-skinned tectonics.

scholarly journals Delayed and rapid deglaciation of alpine valleys in the Sawatch Range, southern Rocky Mountains, USA

2020 ◽  
Author(s):  
Joseph P. Tulenko ◽  
William Caffee ◽  
Avriel D. Schweinsberg ◽  
Jason P. Briner ◽  
Eric M. Leonard
Keyword(s):  
Last Glacial Maximum ◽  
North Atlantic ◽  
North American ◽  
Rocky Mountains ◽  
Ice Sheets ◽  
Last Glacial ◽  
Southern Rocky Mountains ◽  
The North ◽  
The North Atlantic ◽  
Sawatch Range

Abstract. We quantify retreat rates for three alpine glaciers in the Sawatch Range of the southern Rocky Mountains following the Last Glacial Maximum using 10Be ages from ice-sculpted, valley-floor bedrock transects and statistical analysis via the BACON program in R. Glacier retreat in the Sawatch Range from at (100 %) or near (~ 83 %) Last Glacial Maximum extents initiated between 16.3 and 15.6 ka and was complete by 14.2–13.7 ka at rates ranging between 9.9 and 19.8 m a−1. Deglaciation in the Sawatch Range commenced ~ 2–3 kyr later than the onset of rising global CO2, but approximately in-step with rising temperatures observed in the North Atlantic region at the Heinrich Stadial 1/Bølling transition. Our results highlight a possible teleconnection between the North Atlantic sector and the southern Rocky Mountains. However, deglaciation in the Sawatch Range also approximately aligns with the timing of Great Basin pluvial lake lowering. Recent data-modeling comparison efforts highlight the influence of the large North American ice sheets on climate in the western United States, and we hypothesize that recession of the North American ice sheets may have influenced the timing and rate of deglaciation in the Sawatch Range. While we cannot definitively argue for exclusively North Atlantic forcing or North American ice sheet forcing, our data demonstrate the importance of regional forcing mechanisms on past climate records.

scholarly journals Delayed and rapid deglaciation of alpine valleys in the Sawatch Range, southern Rocky Mountains, USA

Geochronology ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 245-255
Author(s):  
Joseph P. Tulenko ◽  
William Caffee ◽  
Avriel D. Schweinsberg ◽  
Jason P. Briner ◽  
Eric M. Leonard
Keyword(s):  
Last Glacial Maximum ◽  
North Atlantic ◽  
North American ◽  
Rocky Mountains ◽  
Ice Sheets ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Southern Rocky Mountains ◽  
The North ◽  
Sawatch Range

Abstract. We quantify retreat rates for three alpine glaciers in the Sawatch Range of the southern Rocky Mountains following the Last Glacial Maximum using 10Be ages from ice-sculpted, valley-floor bedrock transects and statistical analysis via the BACON program in R. Glacier retreat in the Sawatch Range from at (100 %) or near (∼83 %) Last Glacial Maximum extents initiated between 16.0 and 15.6 ka and was complete by 14.2–13.7 ka at rates ranging between 35.6 and 6.8 m a−1. Deglaciation in the Sawatch Range commenced ∼2–3 kyr later than the onset of rising global CO2 and prior to rising temperatures observed in the North Atlantic region at the Heinrich Stadial 1–Bølling transition. However, deglaciation in the Sawatch Range approximately aligns with the timing of Great Basin pluvial lake lowering. Recent data–modeling comparison efforts highlight the influence of the large North American ice sheets on climate in the western United States, and we hypothesize that recession of the North American ice sheets may have influenced the timing and rate of deglaciation in the Sawatch Range. While we cannot definitively argue for exclusively North Atlantic forcing or North American ice sheet forcing, our data demonstrate the importance of regional forcing mechanisms for past climate records.

Studies of the Salix lucida and Salix reticulata complexes in North America

1986 ◽  
Vol 64 (3) ◽  
pp. 541-551 ◽  
Author(s):  
George W. Argus
Keyword(s):  
North America ◽  
Morphological Variation ◽  
Rocky Mountains ◽  
Rocky Mountain ◽  
Western North America ◽  
Northeastern North America ◽  
Southern Rocky Mountains ◽  
The North ◽  
Rocky Mountain Region ◽  
Hybridization And Introgression

A study of morphological variation in the Salix lucida complex revealed three geographical races: one in northeastern North America, a second in western North America extending from Alaska to California, and a third in the southern Rocky Mountains, S. lucida ssp. lucida, Salix lucida ssp. lasiandra comb, nov., and Salix lucida ssp. caudata comb, nov., respectively. The Salix reticulata complex in the Rocky Mountain region is represented by two geographical races, ssp. reticulata in the north and ssp. nivalis in the south. Variation in ssp. nivalis suggests that hybridization and introgression occur where the two races overlap, and that the results of past hybridization are still evident in the southern Rocky Mountains.

Mitbringsel aus den Ferien

Praxis ◽  
2005 ◽  
Vol 94 (47) ◽  
pp. 1869-1870
Author(s):  
Balestra ◽  
Nüesch
Keyword(s):  
Rocky Mountains ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
Rickettsia Conorii ◽  
Rocky Mountain Spotted Fever ◽  
Klinische Diagnose ◽  
Rickettsia Rickettsii

Eine 37-jährige Patientin stellt sich nach der Rückkehr von einer Rundreise durch Nordamerika mit einem Status febrilis seit zehn Tagen und einem makulösem extremitätenbetontem Exanthem seit einem Tag vor. Bei suggestiver Klinik und Besuch der Rocky Mountains wird ein Rocky Mountain spotted fever diagnostiziert. Die Serologie für Rickettsia conorii, die mit Rickettsia rickettsii kreuzreagiert, war positiv und bestätigte die klinische Diagnose. Allerdings konnte der beweisende vierfache Titeranstieg, möglicherweise wegen spät abgenommener ersten Serologie, nicht nachgewiesen werden. Nach zweiwöchiger antibiotischer Therapie mit Doxycycline waren Status febrilis und Exanthem regredient.

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