scholarly journals Glaciolacustrine Sedimentation During Advance and Retreat of the Cordilleran Ice Sheet in Central British Colombia

2007 ◽  
Vol 45 (3) ◽  
pp. 317-331 ◽  
Author(s):  
Nicholas Eyles ◽  
John J. Clague
Keyword(s):  
Debris Flow ◽  
Lake Sediments ◽  
Seasonal Pattern ◽  
Drainage System ◽  
Sediment Fluxes ◽  
British Colombia ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet ◽  
River Valleys ◽  
High Sediment

ABSTRACT Thick (400+ m) and well exposed sediment fills in the Fraser and Chilcotin river valleys of central British Columbia record contrasting glaciolacustrine environments of at least two glaciations. The oldest glaciolacustrine sequence comprises deformed gravel, sand, mud, and diamict fades deposited, in part, on stagnant ice trapped in deep narrow valleys at the end of the penultimate glaciation (Early Wisconsinan or older). Younger glaciolacustrine sequences date from the advance and retreat phases of the Late Wisconsinan Fraser Glaciation {ca. 25-10 ka) and infill a Middle Wisconsinan drainage system cut across older sediments. The Late Wisconsinan advance sequence is dominated by diamict (debris-flow) fades that pass upward into silts. The diamict fades consist largely of reworked older Pleistocene drift and poorly lithified Cretaceous and Tertiary sediments. They record the focusing of large volumes of sediment into one or more glacial lakes occupying deep narrow troughs. Weakly bedded silts in the upper part of the sequence may have been deposited when the lake(s) deepened as glaciers continued to advance and thicken over the study area. It is possible that some advance glaciolacustrine sediments accumulated in subglacial water bodies. Late Wisconsinan deglacial lake sediments form a relatively thin, discontinuous capping in the area and conform to classical notions of gladolacustrine sedimentation involving a seasonal or 'varved' regime. In contrast, no seasonal pattern of sedimentation can be identified in older sequences where the overriding influence on deposition has been the presence of steep subaqueous slopes, buried ice masses, and high sediment fluxes; these, in combination, caused near-continuous downslope movement and resedimentation.

scholarly journals The Cordilleran Ice Sheet in Northern British Colombia

2007 ◽  
Vol 45 (3) ◽  
pp. 355-363 ◽  
Author(s):  
June M. Ryder ◽  
Denny Maynard
Keyword(s):  
Early Phase ◽  
Ice Sheet ◽  
Drainage System ◽  
Ice Flow ◽  
Outlet Glacier ◽  
Radiocarbon Dates ◽  
Coast Mountains ◽  
British Colombia ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

ABSTRACT Dates from lavas associated with tills and erratics indicate that ice-sheet glaciations occurred between 4 and 0.6 Ma BP. The few radiocarbon dates that are available suggest that the chronology of the Late Wisconsinan (Fraser Glaciation) ice sheet of northern British Columbia was similar to that of the southern part of the province. During what may have been a long, early phase of this glaciation, Glacial Lake Stikine was dammed by advancing valley glaciers in the Coast Mountains, and alpine glaciers developed on the intermontane plateau. At the climax of Fraser Glaciation, ice-flow patterns were dominated by outflow from a névé centred over the northern Skeena Mountains. Déglaciation occurred partly by frontal retreat of ice tongues and partly by downwasting of stagnant ice. Recessional moraines mark one or more resurgences or stillstands of the ice margin. During déglaciation, Stikine River valley was occupied by an active outlet glacier and a major subglacial drainage system.

scholarly journals Polyphase Glacigenic Deformation of Advance Glaciofluvial Sediments, Near Big Creek, British Colombia

2007 ◽  
Vol 47 (2) ◽  
pp. 211-219 ◽  
Author(s):  
David H. Huntley ◽  
Bruce E. Broster
Keyword(s):  
British Columbia ◽  
Brittle Failure ◽  
Lateral Extension ◽  
Polyphase Deformation ◽  
Deformation Structures ◽  
Vertical Extension ◽  
British Colombia ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet ◽  
Sheet Deformation

ABSTRACT Deformation structures were observed in glaciofluvial sediments near Big Creek, central British Columbia. These sediments record a sequence of polyphase deformation resulting from the advance and retreat of the Late Wisconsinan (Fraser Glaciation) Cordilleran Ice Sheet. Deformation is attributed to ductile then brittle failure resulting from: (a) horizontal compression and loading as ice advanced over saturated sediments; followed by (b) lateral extension then (c) compression under frozen conditions during glacier overriding; and finally (d) vertical extension during unloading upon déglaciation. Most deformation (a-c, above) appears to have occurred during the advance phase of the Fraser Glaciation.

Coalescence of late Wisconsinan Cordilleran and Laurentide ice sheets east of the Rocky Mountain Foothills in the Dawson Creek region, northeast British Columbia, Canada

2016 ◽  
Vol 85 (3) ◽  
pp. 409-429 ◽  
Author(s):  
Adrian Scott Hickin ◽  
Olav B. Lian ◽  
Victor M. Levson
Keyword(s):  
British Columbia ◽  
Flow Direction ◽  
Ice Sheet ◽  
Rocky Mountain ◽  
Ice Flow ◽  
Oxygen Isotope Stage ◽  
Digital Elevation ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet ◽  
River Valleys

Geomorphic, stratigraphic and geochronological evidence from northeast British Columbia (Canada) indicates that, during the late Wisconsinan (approximately equivalent to marine oxygen isotope stage [MIS] 2), a major lobe of western-sourced ice coalesced with the northeastern-sourced Laurentide Ice Sheet (LIS). High-resolution digital elevation models reveal a continuous 75 km-long field of streamlined landforms that indicate the ice flow direction of a major northeast-flowing lobe of the Cordilleran Ice Sheet (CIS) or a montane glacier (>200 km wide) was deflected to a north-northwest trajectory as it coalesced with the retreating LIS. The streamlined landforms are composed of till containing clasts of eastern provenance that imply that the LIS reached its maximum extent before the western-sourced ice flow crossed the area. Since the LIS only reached this region in the late Wisconsinan, the CIS/montane ice responsible for the streamlined landforms must have occupied the area after the LIS withdrew. Stratigraphy from the Murray and Pine river valleys supports a late Wisconsinan age for the surface landforms and records two glacial events separated by a non-glacial interval that was dated to be of middle Wisconsinan (MIS 3) age.

scholarly journals The Cordilleran Ice Sheet and the Glacial Geomorphology of Southern and Central British Colombia

2007 ◽  
Vol 45 (3) ◽  
pp. 365-377 ◽  
Author(s):  
June M. Ryder ◽  
Robert J. Fulton ◽  
John J. Clague
Keyword(s):  
Ice Sheet ◽  
Late Glacial ◽  
Middle Pleistocene ◽  
Sea Level Changes ◽  
Coast Mountains ◽  
Glacial Sediments ◽  
Late Tertiary ◽  
British Colombia ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

ABSTRACT This paper reviews the current state of knowledge about the Cordilleran Ice Sheet in southern and central British Columbia. Reconstructions of the ice sheet and the styles of ice expansion and déglaciation are based on extensive and varied glacigenic sediments and landforms that date from Late Wisconsinan (Fraser) Glaciation. Late-glacial lakes and sea level changes are also described and related to isostatic and eustatic effects. The timing of ice expansion and recession during Fraser Glaciation was markedly asymmetric: ice build-up commenced about 29 000 years BP, culminated between 14 500 and 14 000 years BP1 and déglaciation was largely completed by 11 500 years BP. Most of this interval appears to have been dominated by montane glaciation, which produced striking erosional landforms. A Cordilleran Ice Sheet existed from only about 19 000 to 13 500 years BP. An older glaciation, probably of Early Wisconsinan age, has been recognized from widespread exposures of drift that underlies Middle Wisconsinan non-glacial sediments. Pre-Wisconsinan drift is present near Vancouver. Drifts of late Tertiary to Middle Pleistocene age have been dated by association with volcanic sequences in the southern Coast Mountains and the central Interior, and by paleomagnetic studies in the southern Interior.

Ice-free conditions in southwestern British Columbia at 16000 years BP

1988 ◽  
Vol 25 (6) ◽  
pp. 938-941 ◽  
Author(s):  
John J. Clague ◽  
Ian R. Saunders ◽  
Michael C. Roberts
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Radiocarbon Dates ◽  
Maximum Extent ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

New radiocarbon dates on wood from two exposures in Chilliwack valley, southwestern British Columbia, indicate that this area was ice free and locally forested 16 000 radiocarbon years ago. This suggests that the Late Wisconsinan Cordilleran Ice Sheet reached its maximum extent in this region after 16 000 years BP. The Chilliwack valley dates are the youngest in British Columbia that bear on the growth of the Cordilleran Ice Sheet.

Source and Origin of Roxana Silt and Middle Wisconsinan Midcontinent Glacial Activity

1989 ◽  
Vol 31 (3) ◽  
pp. 319-331 ◽  
Author(s):  
W. Hilton Johnson ◽  
Leon R. Follmer
Keyword(s):  
Mississippi River ◽  
Lake Michigan ◽  
Drainage System ◽  
River Valley ◽  
Upper Mississippi River ◽  
Upper Great Lakes ◽  
Mississippi River Valley ◽  
Depositional System ◽  
Stratigraphic Position ◽  
Late Wisconsinan

AbstractThick Roxana Silt (middle Wisconsinan) in central and southwestern Illinois traditionally has been interpreted as loess derived from valley-train deposits in the ancient Mississippi River valley. Winters et al. (H. A. Winters, J. J. Alford, and R. L. Rieck, Quaternary Research 29, 25–35, 1988) recently suggested that the Roxana was not directly related to glacial activity, but was derived from sediment produced by increased shoreline and spillway erosion associated with a fluctuating ancestral Lake Michigan. Because (1) paleoenvironmental and paleohydrologic conditions inferred in the hypothesis are unlikely for a loess depositional system and (2) loess did not accumulate during late Wisconsinan deglaciation under conditions similar to those hypothesized, we suggest the hypothesis should be rejected. Roxana distribution suggests the major source was drainage from the upper Mississippi River valley, and variations in loess thickness in Illinois can be explained by consideration of valley width, depth, orientation, and postdepositional erosion. Tills in the headwaters region of the ancient Mississippi drainage system in Minnesota and Wisconsin occur in the appropriate stratigraphic position and have colors and mineralogic compositions that suggest they could be the parent till of the Roxana. We believe a valley-train source for thick Roxana is most probable and urge continued consideration of middle Wisconsinan glaciation in the upper Great Lakes area.

Laurentide and montane glaciation along the Rocky Mountain Foothills of northeastern British Columbia

2007 ◽  
Vol 44 (4) ◽  
pp. 445-457 ◽  
Author(s):  
Jan M Bednarski ◽  
I Rod Smith
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Rocky Mountain ◽  
Laurentide Ice Sheet ◽  
Cosmogenic Dating ◽  
Surficial Geology ◽  
Continental Divide ◽  
Mountain Front ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

Mapping the surficial geology of the Trutch map area (NTS 94G) provides new data on the timing of continental and montane glaciations along the Foothills of northeastern British Columbia. Striated surfaces on mountain crests were dated to the Late Wisconsinan substage by cosmogenic dating. The striations were produced by eastward-flowing ice emanating from the region of the Continental Divide. This ice was thick enough to cross the main ranges and overtop the Rocky Mountain Foothill summits at 2000 m above sea level (asl). It is argued here that such a flow, unhindered by topography, could only have been produced by the Cordilleran Ice Sheet and not by local cirque glaciation. During this time, the Cordilleran Ice Sheet dispersed limestone and schist erratics of western provenance onto the plains beyond the mountain front. Conversely, the Laurentide Ice Sheet did not reach its western limit in the Foothills until after Cordilleran ice retreated from the area. During its maximum, the Laurentide ice penetrated the mountain valleys up to 17 km west of the mountain front, and deposited crystalline erratics from the Canadian Shield as high as 1588 m asl along the Foothills. In some valleys a smaller montane advance followed the retreat of the Laurentide Ice Sheet.

Impact of urbanization on hydrologic response of a small Ontario watershed

1986 ◽  
Vol 13 (6) ◽  
pp. 620-630 ◽  
Author(s):  
D. J. Cook ◽  
W. T. Dickinson
Keyword(s):  
Seasonal Pattern ◽  
Large Diameter ◽  
Drainage System ◽  
Fold Increase ◽  
Annual Runoff ◽  
Water Runoff ◽  
Hydrologic Response ◽  
Unit Hydrograph ◽  
Open Drainage ◽  
Spring Runoff

The Speedvale Experimental Basin, a 210 ha watershed on the outskirts of Guelph, Ontario, was established in 1965 as an International Hydrological Decade project for the purpose of studying impacts of urbanization on hydrologic response. A relatively extensive hydrologic database regarding precipitation, streamflow, soil moisture, and groundwater has been assembled for the preurbanization period from 1966 to 1974 and for the period of ongoing development from 1975 to 1982. The study area, located physiographically within the Guelph Drumlin Field, was used for mixed agricultural purposes prior to 1974. During 1975 and 1976, 155 ha of the basin were serviced for development for light industrial and commercial usage, dramatically altering the configuration of the drainage system. The major alteration was the installation of a stormwater conveyance system, consisting of a large-diameter storm sewer (2.5 and 3.0 m) and a network of open drainage ditches outletting through ditch inlet catch basins into a main drainage channel.With the changes in land use in the basin have come changes in both volumetric and time distribution aspects of hydrologic response. Changes in the response include (i) an increase in the mean annual runoff coefficient by a factor of 1.5, (ii) an increase in the average annual maximum instantaneous discharge by a factor of almost 3.0, (iii) a change in the time of the annual peak flow from occurring solely in the spring runoff period to occurring throughout the various seasons, (iv) a change in the seasonal pattern of monthly runoff coefficients, with the greatest change observed in the summer and lesser changes observed in the other seasons, (v) a 3-fold reduction in unit hydrograph lag time, and (vi) a 3.5-fold increase in unit hydrograph peak discharge. Key words: urbanization, hydrology, surface water runoff, streamflow, watersheds.

scholarly journals Late Wisconsinan Glacial Geomorphology of the Kent Interlobate Complex, Ohio, USA

Finisterra ◽  
2012 ◽  
Vol 47 (93) ◽  
Author(s):  
João Bessa Santos
Keyword(s):  
Debris Flow ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Geomorphology ◽  
Long Run ◽  
Gravel Pits ◽  
Late Wisconsinan ◽  
Sand And Gravel ◽  
Northern Sector

The northern sector of the Kent Interlobate Complex, created by twomajor ice lobes of the Laurentide Ice Sheet during late Wisconsinan times, dominates theglacial landscape of northeast Ohio. The geomorphology of this impressive complex revealsthe presence of large hummocks, kettle lakes and substantial esker chains. The esker chains,usually smaller than 1.3 km long, run parallel to the interlobate complex geographicorientation of northeast-southwest. Gravel pits present on large hummocks display beddedand sorted sedimentary units of gravel, sand and gravel and climbing ripple laminated sandwith folds, which demonstrate that the northern sector of the interlobate complex isprimarily a glaciofluvial feature. Topping these hummocks is a massive clast-supporteddiamicton interpreted to be a debris flow. These geomorphic and sedimentary characteristicsseem to indicate that hummocks present in the interlobate area are in fact kames and that theentire northern sector of the interlobate complex is a product of late Wisconsinan timetransgressive ice stagnation that occurred between two major ice lobes.

scholarly journals Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: I. Field evidence

1998 ◽  
Vol 44 (148) ◽  
pp. 547-562 ◽  
Author(s):  
Daniel E. Lawson ◽  
Jeffrey C. Strasser ◽  
Edward B. Evenson ◽  
Richard B. Alley ◽  
Grahame J. Larson ◽  
...  
Keyword(s):  
Great Lakes ◽  
Growth Rates ◽  
Drainage System ◽  
Laurentian Great Lakes ◽  
Sediment Fluxes ◽  
Frazil Ice ◽  
Heinrich Events ◽  
Basal Ice ◽  
Field Evidence ◽  
Matanuska Glacier

AbstractDebris-laden ice accretes to the base of Matanuska Glacier, Alaska, U.S.A., from water that supercools while flowing in a distributed drainage system tip the adverse slope of an overdeepening. Frazil ice grows in the water column and forms aggregates, while other ice grows on the glacier sole or on substrate materials. Sediment is trapped by this growing ice, forming stratified debris-laden basal ice. Growth rates of >0.l ma−1of debris-rich basal ice are possible. The large sediment fluxes that this mechanism allows may have implications for interpretation of the widespread deposits from ice that flowed through other overdeepenings, including Heinrich events and the till sheets south of the Laurentian Great Lakes.

Sign in / Sign up

Export Citation Format

Share Document