Rates and environmental controls of aeolian dust accumulation, Athabasca River Valley, Canadian Rocky Mountains

Geomorphology ◽  
2010 ◽  
Vol 121 (3-4) ◽  
pp. 274-282 ◽  
Author(s):  
Chris H. Hugenholtz ◽  
Stephen A. Wolfe
Keyword(s):  
Rocky Mountains ◽  
River Valley ◽  
Canadian Rocky Mountains ◽  
Athabasca River ◽  
Aeolian Dust ◽  
Environmental Controls ◽  
Dust Accumulation

scholarly journals II.—On a Sodalite Syenite (Ditroite) from Ice River Valley, Canadian Rocky Mountains

1902 ◽  
Vol 9 (5) ◽  
pp. 199-206 ◽  
Author(s):  
T. G. Bonney
Keyword(s):  
Rocky Mountains ◽  
British Museum ◽  
River Valley ◽  
Microscopic Structure ◽  
Canadian Rocky Mountains ◽  
Mode Of Occurrence ◽  
Lapis Lazuli

In the year 1886 the late Dr. G. M. Dawson gave an account of a syenitic rock, rich in a beautiful blue sodalite, which he had discovered when exploring the district near Hector Pass, on the watershed of the Canadian Rocky Mountains, and an analysis of the mineral was afterwards published by Professor Harrington. The place was visited last Summer by Mr. E. Whymper during his examination of the district south of the Canada Pacific Railway, when he collected a number of specimens, which he showed to me on his return. The rock is hardly less beautiful than lapis lazuli, and as no description of its microscopic structure has been published, as far as I can ascertain, I give the results of my examination, together with a condensed account of its mode of occurrence. I am much indebted to Mr. Whymper for placing his specimens at my disposal, to Mr. L. Fletcher, Keeper of the Mineral Collection in the British Museum, for the opportunity of examining specimens of sodalite rock not in my own cabinet, and to Mr. L. J. Spencer, of that department, for giving me his kind assistance and valuable references to papers about the mineral.

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.

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

scholarly journals Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Corey R Froese ◽  
David M Cruden
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Carbonate Content ◽  
Canadian Rocky Mountains ◽  
Density Profiles ◽  
Frost Action ◽  
Dominant Component ◽  
Freeze And Thaw ◽  
Calcite Cement ◽  
The Relationship

Slopes in weakly cemented glaciolacustrine sediments in the Morkill River valley in the Canadian Rocky Mountains stand at up to 70°. Based on field and laboratory observations it appears that a contributing factor to instability is the softening of the soils by frost action and the leaching of calcite cement. Field density profiles demonstrated increased density and carbonate content with an increase in depth. Laboratory tests of carbonate content indicated a positive correlation between calcium carbonate and density in the glaciolacustrine sediments. The relationship was strongest in sands, in which leaching and dissolution were important components of softening. In clays, frost action was the dominant component of softening. Freeze-thaw tests showed a 50% decrease in strength after one cycle of freeze and thaw in the silts and clays.Key words: landslide, cemented, glaciolacustrine sediments, British Columbia.

Spatial and temporal variations of fire regimes in the Canadian Rocky Mountains and Foothills of southern Alberta

2016 ◽  
Vol 25 (11) ◽  
pp. 1117 ◽  
Author(s):  
Marie-Pierre Rogeau ◽  
Mike D. Flannigan ◽  
Brad C. Hawkes ◽  
Marc-André Parisien ◽  
Rick Arthur
Keyword(s):  
Rocky Mountains ◽  
Fire History ◽  
Fire Severity ◽  
Ecological Integrity ◽  
Fire Regimes ◽  
Temporal Variations ◽  
Fire Season ◽  
Canadian Rocky Mountains ◽  
Southern Alberta ◽  
Fire Exclusion

Like many fire-adapted ecosystems, decades of fire exclusion policy in the Rocky Mountains and Foothills natural regions of southern Alberta, Canada are raising concern over the loss of ecological integrity. Departure from historical conditions is evaluated using median fire return intervals (MdFRI) based on fire history data from the Subalpine (SUB), Montane (MT) and Upper Foothills (UF) natural subregions. Fire severity, seasonality and cause are also documented. Pre-1948 MdFRI ranged between 65 and 85 years in SUB, between 26 and 35 years in MT and was 39 years in UF. The fire exclusion era resulted in a critical departure of 197–223% in MT (MdFRI = 84–104 years). The departure in UF was 170% (MdFRI = 104 years), while regions of continuous fuels in SUB were departed by 129% (MdFRI = 149 years). The most rugged region of SUB is within its historical range of variation with a departure of 42% (MdFRI = 121 years). More mixed-severity burning took place in MT and UF. SUB and MT are in a lightning shadow pointing to a predominance of anthropogenic burning. A summer fire season prevails in SUB, but occurs from spring to fall elsewhere. These findings will assist in developing fire and forest management policies and adaptive strategies in the future.

New Lower Jurassic ammonite faunas from the Fernie Formation, southern Canadian Rocky Mountains

1987 ◽  
Vol 24 (8) ◽  
pp. 1688-1704 ◽  
Author(s):  
Russell L. Hall
Keyword(s):  
British Columbia ◽  
North American ◽  
Rocky Mountains ◽  
Red Deer ◽  
First Record ◽  
Lower Jurassic ◽  
Canadian Rocky Mountains ◽  
Poker Chip

New ammonite faunas are described from sections along Bighorn and Scalp creeks in central-western Alberta where Lower Jurassic parts of the Fernie Formation are exposed. The first record of the upper Sinemurian Obtusum Zone from the Fernie is based on the occurrence of Asteroceras cf. stellare and Epophioceras cf. breoni in the basal pebbly coquina on Bighorn Creek. The overlying Red Deer Member has yielded Amaltheus cf. stokesi, representing the upper Pliensbachian Margaritatus Zone; in immediately superjacent strata the first North American examples of ?Amauroceras occur together with Protogrammoceras and ?Aveyroniceras. In the basal parts of the overlying Poker Chip Shale a fauna including Harpoceras cf. falciferum, Harpoceratoides, Polyplectus cf. subplanatus, Hildaites cf. serpentiniformis, and Dactylioceras cf. athleticum is correlated with the lower Toarcian Falciferum Zone.The upper parts of the Poker Chip Shale on Fording River in southeastern British Columbia contain a fauna representing some part of the upper Toarcian, but owing to poor preservation, generic identifications are only tentatively made.

Sign in / Sign up

Export Citation Format

Share Document