Paraglacial origin for terraced river sediments in Bow Valley, Alberta

1982 ◽  
Vol 19 (12) ◽  
pp. 2219-2231 ◽  
Author(s):  
Lionel E. Jackson Jr. ◽  
Glen M. MacDonald ◽  
Michael C. Wilson
Keyword(s):  
Single Channel ◽  
Sedimentary Environment ◽  
River Sediments ◽  
Early Period ◽  
Rocky Mountain ◽  
Radiocarbon Dates ◽  
Fluvial Terraces ◽  
Mountain Front ◽  
Main Period ◽  
Glacial Advance

Fluvial terraces flank the course of the Bow River for 100 km from the eastern margin of the Rocky Mountain Front Ranges to Calgary and beyond. The terraces are cut predominantly in gravel fill, which ranges in thickness from approximately 10 m in the Calgary area to 30 m near the mountain front. Sedimentary structures in the gravels indicate a braided stream sedimentary environment in contrast to the present quasi-stable, sinuous, single-channel form of the Bow River. Radiocarbon dates on ungulate remains from the gravels indicate the main period of fill occurred ca. 11 500–10 000 RCYBP (radiocarbon years before present). Previous workers have postulated that the gravels originated directly as outwash from a glacial advance to or beyond the mountain front. This explanation has been refuted by recent stratigraphic and palynological investigations. A complex nonglaciofluvial origin is proposed for these terraces and the sediments that form them. The last glacial advance to reach the mountain front was well into retreat by as early as ca. 13 400 RCYBP. Spruce and pine forest was established in the Bow River drainage by ca. 10 400–10 000 RCYBP and glaciers were restricted to high cirques. It is probable that the early period of fill deposition (ca. 11 500–10 000 RCYBP) was initiated when mountain tributary trunk streams of the Bow River were choked with debris-flow-delivered sediment during the construction of paraglacial debris fans and related phenomena. The debris flows were distinctive features of early nonglacial times, when landforms left unstable by ice retreat mass-wasted into the valleys. Paraglacial processes explain the early postglacial history of the Bow drainage and this example provides a model readily applicable to other drainages in formerly glaciated terrain.

Dating fluvial terraces by 230Th/U on pedogenic carbonate, Wind River Basin, Wyoming

2003 ◽  
Vol 59 (2) ◽  
pp. 139-150 ◽  
Author(s):  
Warren D. Sharp ◽  
Kenneth R. Ludwig ◽  
Oliver A. Chadwick ◽  
Ronald Amundson ◽  
Laura L. Glaser
Keyword(s):  
River Basin ◽  
Rocky Mountain ◽  
Ionization Mass ◽  
Glacial Cycle ◽  
Pedogenic Carbonate ◽  
Fluvial Terraces ◽  
Ice Volume ◽  
Wind River Basin ◽  
Cosmogenic Nuclide Dating ◽  
Glacial Advance

AbstractReliable and precise ages of Quaternary pedogenic carbonate can be obtained with 230Th/U dating by thermal ionization mass spectrometry applied to carefully selected milligram-size samples. Datable carbonate can form within a few thousand years of surface stabilization allowing ages of Quaternary deposits and surfaces to be closely estimated. Pedogenic carbonate clast-rinds from gravels of glacio-fluvial terraces in the Wind River Basin have median concentrations of 14 ppm U and 0.07 ppm 232Th, with median (230Th/232Th) = 270, making them well suited for 230Th/U dating. Horizons as thin as 0.5 mm were sampled from polished slabs to reduce averaging of long (≥105 yr), and sometimes visibly discontinuous, depositional histories. Dense, translucent samples with finite 230Th/U ages preserve within-rind stratigraphic order in all cases. Ages for terraces WR4 (167,000 ± 6,400 yr) and WR2 (55,000 ± 8600 yr) indicate a mean incision rate of 0.26 ± 0.05 m per thousand years for the Wind River over the past glacial cycle, slower than inferred from cosmogenic-nuclide dating. Terrace WR3, which formed penecontemporaneously with the final maximum glacial advance of the penultimate Rocky Mountain (Bull Lake) glaciation, has an age of 150,000 ± 8300 yr indicating that it is broadly synchronous with the penultimate global ice volume maximum.

Cordilleran and Laurentide Multiple Glaciation West-Central Alberta, Canada

1975 ◽  
Vol 12 (9) ◽  
pp. 1493-1515 ◽  
Author(s):  
Murray A. Roed
Keyword(s):  
United States Of America ◽  
Rocky Mountain ◽  
The United States ◽  
Lake Area ◽  
Mountain Area ◽  
Radiocarbon Dates ◽  
Marsh Creek ◽  
Glacier Advance ◽  
Late Stages ◽  
Glacial Advance

Informal rock stratigraphic units have been established for the area. They consist of the Marlboro, Raven Creek, Obed, and Drystone Creek tills of Cordilleran provenance, and the Marsh Creek, Edson, and Mayberne tills of Canadian Shield or Laurentide source. Three different gravel units of Tertiary–Quaternary age underlie glacial deposits of the area and are here called the Tableland, Lowland, and Buried Valley gravel, in order of decreasing age.Evidence for four and possibly five glacier advances has been recognized. The oldest is inferred by fragmentary evidence of an 'Early' Cordilleran till. The second, represented by the Marsh Creek till, is the initial and greatest advance of Laurentide ice into the area. In the third both Cordilleran and Laurentide glaciers advanced and met. The Cordilleran ice is recorded by the Marlboro and Raven Creek tills, and the Laurentide by the Edson and Mayberne tills. The fourth glacial advance is documented by the Obed till of Cordilleran source. The Hinton terraces were formed during retreat of this glacier. The last glacier advance is indicated by the Drystone Creek till present in small valleys at the mountain front.Although radiocarbon dates are not available, the Marlboro, Obed, and Drystone Creek Cordilleran ice advances may represent the Early, Middle, and Late Stages of the Pinedale Glaciation (classical Wisconsin) of the Rocky Mountain area of the United States of America. Broadly correlative Cordilleran glacial advances occurred in the Banff area and the Williston Lake area of British Columbia.

Oral tradition as emplacement: Ancestral Blackfoot memories of the Rocky Mountain Front

2021 ◽  
pp. 146960532110198
Author(s):  
María Nieves Zedeño ◽  
Evelyn Pickering ◽  
François Lanoë
Keyword(s):  
Oral Tradition ◽  
Rocky Mountain ◽  
Place Making ◽  
Human Presence ◽  
Archaeological Practice ◽  
Intimate Connection ◽  
Origin Stories ◽  
Mountain Front ◽  
Process Event ◽  
Early Human

We highlight the significance of process, event, and context of human practice in Indigenous Creation traditions to integrate Blackfoot “Napi” origin stories with environmental, geological, and archaeological information pertaining to the peopling of the Northwestern Plains, where the northern Rocky Mountain Front may have played a prominent role. First, we discuss the potential and limitations of origin stories generally, and Napi stories specifically, for complementing the fragmentary records of early human presence in the Blackfoot homeland. Second, we demonstrate the intimate connection among processes, events, place-making practices, and stories. Last, we aim to expand multivocality in the interpretation of the deep past through an archaeological practice that considers Indigenous philosophies and stories to be as valid as non-Indigenous ones.

scholarly journals Sedimentological characteristics of ice-wedge polygon terrain in Adventdalen (Svalbard) – environmental and climatic implications for the late Holocene

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 901-914 ◽  
Author(s):  
M. Oliva ◽  
G. Vieira ◽  
P. Pina ◽  
P. Pereira ◽  
M. Neves ◽  
...  
Keyword(s):  
Organic Matter Content ◽  
Soil Formation ◽  
Matter Content ◽  
Valley Bottom ◽  
Radiocarbon Dates ◽  
Climate Conditions ◽  
Fluvial Terraces ◽  
Ice Wedge ◽  
Homogeneous Composition ◽  
Climatic Severity

Abstract. Ice wedges are widespread periglacial features in the landscape of Adventdalen, Svalbard. The networks of ice wedges have created areas with well-developed polygonal terrains in the lowest fluvial terraces in this valley. We have examined the sedimentological characteristics of the northern and southern banks of the Advent river for palaeoenvironmental purposes. The base of two sedimentary sections reported radiocarbon dates of 3.3 and 3.9 ka BP, respectively. The northern site is constituted by three very different lithostratigraphical units, which suggests that their formation should be related to different environmental and climate conditions. By contrast, the southern section shows a rather homogeneous composition, with no significant variations in grain size and organic matter content. In both cases the uppermost sediments are constituted by a thick aeolian deposit. According to our data, warmer climate conditions may have prevailed during the mid Holocene until 3.3 ka BP with widespread peat formation in the valley bottom. Subsequently, a period with alternating soil formation and aeolian sedimentation took place from 3 to 2.5 ka BP, probably due to increasing climatic severity. During the last millennium a long-term cooling trend has favoured aeolian deposition in the lowest part of Adventdalen.

scholarly journals Water chemistry of Rocky Mountain Front Range aquatic ecosystems

1996 ◽  
Author(s):  
Robert C. Musselman ◽  
Laura Hudnell ◽  
Mark W. Williams ◽  
Richard A. Sommerfeld
Keyword(s):  
Water Chemistry ◽  
Aquatic Ecosystems ◽  
Rocky Mountain ◽  
Front Range ◽  
Mountain Front

Late Quaternary history of the Lake O'Hara region, British Columbia – an evaluation of sedimentation rates and bulk amino acid ratios in lacustrine records

1988 ◽  
Vol 25 (7) ◽  
pp. 1037-1048 ◽  
Author(s):  
Mel A. Reasoner ◽  
Nathaniel W. Rutter
Keyword(s):  
Amino Acid ◽  
Aspartic Acid ◽  
Sedimentation Rate ◽  
River Sediments ◽  
Sedimentation Rates ◽  
Rate Data ◽  
Radiocarbon Dates ◽  
Clastic Sediments ◽  
Lake Cores ◽  
Total Sedimentation

Lake O'Hara (subalpine) and Opabin Lake (alpine) are situated directly adjacent to a high section of the Continental Divide in the central Canadian Rocky Mountains. Core samples recovered from the lakes show a consistent stratigraphy comprising gyttja and underlying inorganic clastic sediments. The gyttja contains Bridge River (2350 years BP) and Mazama (6800 years BP) tephras and is separated from the lower clastic sediments by a sharp, conformable contact. Radiocarbon dates obtained from conifer needles, extracted from directly above the contact, indicate that deglaciation had proceeded upvalley from the O'Hara basin priorto ca. 10 100 years BP. Preliminary palaeobotanical and macrofossil data suggest that a Pinus–Abies forest with lesser Picea was established in the vicinity of Lake O'Hara by this time. Consequently, the minimum age of moraine systems situated downvalley from Lake O'Hara is Late Wisconsinan.Mean annual sedimentation rates were derived from sediment thickness data from 14 Lake O'Hara and 2 Opabin Lake cores. Averaged total sedimentation rate values from the Lake O'Hara cores are 0.13 mm/year (post-Bridge River), 0.13 mm/year (Mazama – Bridge River) and 0.05 mm/year (11 000 years BP – Mazama). Averaged total sedimentation rate values from the Opabin Lake cores are 0.19 mm/year (post-Bridge River), 0.07 mm/year (Mazama – Bridge River), and 0.06 mm/year (8530 years BP – Mazama). Higher total sedimentation rates in post-Bridge River sediments of Opabin Lake are presumably related to climatic conditions associated with more extensive upvalley ice during the last ca. 2300 years. Highly variable sedimentation rate data obtained from the Lake O'Hara cores suggest that the use of sedimentation rate data as a proxy record of upvalley glacial activity is inappropriate in the Lake O'Hara setting where inflowing glacial stream systems are interrupted by upvalley lake basins.Aspartic acid D/L ratios were derived from bulk gyttja samples of known age from seven Lake O'Hara and one Opabin Lake core. In all but two cases, aspartic acid D/L ratios increase consistently with respect to sediment age. The increasing downcore trends in the aspartic acid D/L ratios suggest the possibility of using amino acid data from bulk gyttja samples as a check for reworking in cases where chronostratigraphic markers are absent.

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