scholarly journals Evidence for Headwall Weathering Zones, Boundary Glacier, Canadian Rocky Mountains

1987 ◽  
Vol 33 (113) ◽  
pp. 60-67 ◽  
Author(s):  
James S. Gardner
Keyword(s):  
Temperature Regime ◽  
Rocky Mountains ◽  
Freezing Temperature ◽  
Rock Surface ◽  
Canadian Rocky Mountains ◽  
Freeze Thaw ◽  
Thaw Zone ◽  
Potential Factor ◽  
Temperature Records

AbstractTemperature records from severalrandkluftsites at the margins and headwall of Boundary Glacier (lat. 52° 12′ N., long. 117° 12′ W.) in the Canadian Rocky Mountains are presented. These records indicate that during the ablation season a diurnal freeze-thaw air and rock-surface temperature regime occurs in a 2 m wide zone centred on therandkluftlip. Deeper in therandkluft, stable sub-zero conditions prevail whereas above therandkluftan above-freezing temperature regime prevails. The freeze-thaw temperature regime, observed freezing of melt water and rain water onrandkluftrock surfaces, and copiousin-situloose weathering products on the headwall and marginal free faces suggest an active frost-shattering environment. Down-slope migration of therandkluftlip during the ablation season results in a migration of the freeze-thaw zone and thus a seasonal extension of the rock surface area exposed to the favorable weathering environment. Longer-term glacier fluctuations, with attendant thinning and thickening of the ice body, could result in large areas of marginal and headwall rock surfaces being exposed to therandkluftweathering environment over long periods of time. The data and observations from Boundary Glacier support an idea, suggested by Battle (1960), that open and shallowrandklufts, rather than closed and deep bergschrunds, are a focus of weathering at glacier margins and thus a potential factor in cirque development.

scholarly journals Evidence for Headwall Weathering Zones, Boundary Glacier, Canadian Rocky Mountains

1987 ◽  
Vol 33 (113) ◽  
pp. 60-67 ◽  
Author(s):  
James S. Gardner
Keyword(s):  
Temperature Regime ◽  
Rocky Mountains ◽  
Freezing Temperature ◽  
Rock Surface ◽  
Canadian Rocky Mountains ◽  
Freeze Thaw ◽  
Thaw Zone ◽  
Potential Factor ◽  
Temperature Records

AbstractTemperature records from several randkluft sites at the margins and headwall of Boundary Glacier (lat. 52° 12′ N., long. 117° 12′ W.) in the Canadian Rocky Mountains are presented. These records indicate that during the ablation season a diurnal freeze-thaw air and rock-surface temperature regime occurs in a 2 m wide zone centred on the randkluft lip. Deeper in the randkluft, stable sub-zero conditions prevail whereas above the randkluft an above-freezing temperature regime prevails. The freeze-thaw temperature regime, observed freezing of melt water and rain water on randkluft rock surfaces, and copious in-situ loose weathering products on the headwall and marginal free faces suggest an active frost-shattering environment. Down-slope migration of the randkluft lip during the ablation season results in a migration of the freeze-thaw zone and thus a seasonal extension of the rock surface area exposed to the favorable weathering environment. Longer-term glacier fluctuations, with attendant thinning and thickening of the ice body, could result in large areas of marginal and headwall rock surfaces being exposed to the randkluft weathering environment over long periods of time. The data and observations from Boundary Glacier support an idea, suggested by Battle (1960), that open and shallow randklufts, rather than closed and deep bergschrunds, are a focus of weathering at glacier margins and thus a potential factor in cirque development.

Mountain Park: a plant refugium in the Canadian Rocky Mountains

1974 ◽  
Vol 52 (6) ◽  
pp. 1393-1409 ◽  
Author(s):  
John G. Packer ◽  
Dale H. Vitt
Keyword(s):  
Rocky Mountains ◽  
Flowering Plants ◽  
Canadian Rocky Mountains ◽  
Present Distribution ◽  
Angiosperm Species

It is suggested that the area in the vicinity of Mountain Park, Alberta, (52°50′ N; 117°20′ W) in the Canadian Rocky Mountains was a refugium during the Wisconsin period, where alpine and montane bryophytes and flowering plants survived the glaciation in situ. Evidence for this view includes data derived from geological investigations and from the present distribution of a number of bryophyte and angiosperm species. Alternative explanations to account for these distributions are discussed and reasons for rejecting them as highly improbable are presented.

Using 10Be dating to determine when the Cordilleran Ice Sheet stopped flowing over the Canadian Rocky Mountains

2021 ◽  
pp. 1-12
Author(s):  
Helen E. Dulfer ◽  
Martin Margold ◽  
Zbynĕk Engel ◽  
Régis Braucher ◽  
Aster Team
Keyword(s):  
Rocky Mountains ◽  
Ice Sheet ◽  
Mountain Range ◽  
Canadian Rocky Mountains ◽  
Weighted Mean ◽  
Exposure Age ◽  
Western Side ◽  
Cordilleran Ice Sheet ◽  
The Last Glacial

Abstract During the last glacial maximum the Cordilleran and Laurentide ice sheets coalesced east of the Rocky Mountains and geomorphological evidence indicates ice flowed over the main ridge of the Rocky Mountains between ~54–56°N. However, this ice flow has thus far remained unconstrained in time. Here we use in situ produced cosmogenic 10Be dating to determine when Cordilleran ice stopped flowing over the mountain range. We dated eight samples from two sites: one on the western side (Mount Morfee) and one on the eastern side (Mount Spieker) of the Rocky Mountains. At Mount Spieker, one sample is rejected as an outlier and the remaining three give an apparent weighted mean exposure age of 15.6 ± 0.6 ka. The four samples at Mount Morfee are well clustered in time and give an apparent weighted mean exposure age of 12.2 ± 0.4 ka. These ages indicate that Mount Spieker became ice free before the Bølling warming and that the western front of the Rocky Mountains (Mount Morfee) remained in contact with the Cordilleran Ice Sheet until the Younger Dryas.

scholarly journals Daily temperature records from a mesonet in the foothills of the Canadian Rocky Mountains, 2005–2010

2018 ◽  
Vol 10 (1) ◽  
pp. 595-607 ◽  
Author(s):  
Wendy H. Wood ◽  
Shawn J. Marshall ◽  
Terri L. Whitehead ◽  
Shannon E. Fargey
Keyword(s):  
Rocky Mountains ◽  
Monitoring Network ◽  
Daily Temperature ◽  
Spatial Density ◽  
Canadian Rocky Mountains ◽  
Weather System ◽  
Near Surface ◽  
Air Temperatures ◽  
Temperature Records ◽  
Lapse Rates

Abstract. Near-surface air temperatures were monitored from 2005 to 2010 in a mesoscale network of 230 sites in the foothills of the Rocky Mountains in southwestern Alberta, Canada. The monitoring network covers a range of elevations from 890 to 2880 m above sea level and an area of about 18 000 km2, sampling a variety of topographic settings and surface environments with an average spatial density of one station per 78 km2. This paper presents the multiyear temperature dataset from this study, with minimum, maximum, and mean daily temperature data available at https://doi.org/10.1594/PANGAEA.880611. In this paper, we describe the quality control and processing methods used to clean and filter the data and assess its accuracy. Overall data coverage for the study period is 91 %. We introduce a weather-system-dependent gap-filling technique to estimate the missing 9 % of data. Monthly and seasonal distributions of minimum, maximum, and mean daily temperature lapse rates are shown for the region.

Regulation of Rotifers by Predatory Calanoid Copepods (Subgenus Hesperodiaptomus) in Lakes of the Canadian Rocky Mountains

1994 ◽  
Vol 51 (11) ◽  
pp. 2520-2528 ◽  
Author(s):  
Andrew J. Paul ◽  
David W. Schindler
Keyword(s):  
Rocky Mountains ◽  
Logistic Regression Model ◽  
Calanoid Copepod ◽  
Alpine Lakes ◽  
Canadian Rocky Mountains ◽  
Calanoid Copepods ◽  
Order Of Magnitude ◽  
Keratella Quadrata ◽  
Planktonic Rotifers

The abundance of planktonic rotifers in alpine lakes is regulated by predation from Diaptomus (subgenus Hesperodiaptomus) arcticus (a large calanoid copepod) regardless of nutrient conditions. We manipulated both predators and nutrient levels in large in situ enclosure experiments (2250 L). Hesperodiaptomus arcticus suppressed densities of the soft-bodied rotifer Polyarthra dolichoptera significantly (two to three orders of magnitude) and the loricate rotifer Keratella quadrata less so (up to one order of magnitude) relative to populations in predator-free enclosures. Keratella quadrata's armoured lorica may limit predation by Hesperodiaptomus. Nutrient addition resulted in higher phytoplankton standing crops and rotifer densities but did not permit rotifers to exceed predator consumption. In 69 lakes from the Canadian Rocky Mountains, the presence of Keratella or Polyarthra was negatively correlated with Hesperodiaptomus density. A maximum-likelihood logistic regression model predicts that as Hesperodiaptomus densities increase the probability of occurrence for both rotifer genera decreases, with Polyarthra declining more rapidly than Keratella.

Wenkchemna Glacier: ablation complex and rock glacier in the Canadian Rocky Mountains

1978 ◽  
Vol 15 (7) ◽  
pp. 1200-1204 ◽  
Author(s):  
J. Gardner
Keyword(s):  
Rocky Mountains ◽  
Canadian Rocky Mountains ◽  
Rock Glacier ◽  
Active Mass ◽  
Freeze Thaw ◽  
Glacier Ice ◽  
Rock Glaciers ◽  
Climatic System ◽  
Glacier Ablation ◽  
And Behavior

The characteristics and behavior of the Wenkchemna Glacier in the Valley of the Ten Peaks of the Canadian Rocky Mountains are described. Early descriptions, old photographs, tree-rings, an annual sequence of photos since 1965, and field observations provide a data base. The Wenkchemna Glacier combines characteristics of ice-cored rock glaciers, ablation complexes, and glaciers, supporting the concept of a transition between these features. It is the product of a unique geomorphic–climatic system where a large mountain wall of northerly exposure produces a glacial micro–climate, a freeze–thaw weathering environment, a high rockfall frequency, and copious avalanche activity that led, in turn, to a thin, active mass of glacier ice that is preserved by a cover of rock debris. The behavior of the Wenkchemna Glacier has lagged behind that of surrounding glaciers by at least 70 years. Stagnation and differential ablation are the primary processes of glacier wastage. The landforms produced by the Wenkchemna Glacier include rock glacier features, such as arcuate ridges of debris, as well as hummocky ablation moraines typical of glacier stagnation.

scholarly journals Rock Surface Fungi in Deep Continental Biosphere—Exploration of Microbial Community Formation with Subsurface In Situ Biofilm Trap

2020 ◽  
Vol 9 (1) ◽  
pp. 64
Author(s):  
Maija Nuppunen-Puputti ◽  
Riikka Kietäväinen ◽  
Lotta Purkamo ◽  
Pauliina Rajala ◽  
Merja Itävaara ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Debaryomyces Hansenii ◽  
Fungal Communities ◽  
Fungal Colonization ◽  
Rock Surface ◽  
Mica Schist ◽  
Deep Subsurface ◽  
Bacterial Phyla ◽  
In Situ Conditions

Fungi have an important role in nutrient cycling in most ecosystems on Earth, yet their ecology and functionality in deep continental subsurface remain unknown. Here, we report the first observations of active fungal colonization of mica schist in the deep continental biosphere and the ability of deep subsurface fungi to attach to rock surfaces under in situ conditions in groundwater at 500 and 967 m depth in Precambrian bedrock. We present an in situ subsurface biofilm trap, designed to reveal sessile microbial communities on rock surface in deep continental groundwater, using Outokumpu Deep Drill Hole, in eastern Finland, as a test site. The observed fungal phyla in Outokumpu subsurface were Basidiomycota, Ascomycota, and Mortierellomycota. In addition, significant proportion of the community represented unclassified Fungi. Sessile fungal communities on mica schist surfaces differed from the planktic fungal communities. The main bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteriota. Biofilm formation on rock surfaces is a slow process and our results indicate that fungal and bacterial communities dominate the early surface attachment process, when pristine mineral surfaces are exposed to deep subsurface ecosystems. Various fungi showed statistically significant cross-kingdom correlation with both thiosulfate and sulfate reducing bacteria, e.g., SRB2 with fungi Debaryomyces hansenii.

Wildfires in the southern Canadian Rocky Mountains and their relationship to mid-tropospheric anomalies

1993 ◽  
Vol 23 (6) ◽  
pp. 1213-1222 ◽  
Author(s):  
E.A. Johnson ◽  
D.R. Wowchuk
Keyword(s):  
North America ◽  
Rocky Mountains ◽  
Large Scale ◽  
Fire Frequency ◽  
Fuel Moisture ◽  
Large Fire ◽  
Canadian Rocky Mountains ◽  
Area Burned ◽  
Upper Level ◽  
Moisture Conditions

In this paper we present evidence for a large-scale (synoptic-scale) meteorological mechanism controlling the fire frequency in the southern Canadian Rocky Mountains. This large-scale control may explain the similarity in average fire frequencies and timing of change in average fire frequencies for the southern Canadian Rocky Mountains. Over the last 86 years the size distribution of fires (annual area burned) in the southern Canadian Rockies was distinctly bimodal, with a separation between small- and large-fire years at approximately 10–25 ha annual area burned. During the last 35 years, large-fire years had significantly lower fuel moisture conditions and many mid-tropospheric surface-blocking events (high-pressure upper level ridges) during July and August (the period of greatest fire activity). Small-fire years in this period exhibited significantly higher fuel moisture conditions and fewer persistent mid-tropospheric surface-blocking events during July and August. Mid-tropospheric surface-blocking events during large-fire years were teleconnected (spatially and temporally correlated in 50 kPa heights) to upper level troughs in the North Pacific and eastern North America. This relationship takes the form of the positive mode of the Pacific North America pattern.

Canadian Rocky Mountains

1903 ◽  
Vol 21 (6) ◽  
pp. 685
Author(s):  
J. Norman Collie
Keyword(s):  
Rocky Mountains ◽  
Canadian Rocky Mountains
Sign in / Sign up

Export Citation Format

Share Document