scholarly journals Quaternary Stratigraphy in Northwestern Maine: A Progress Report

2007 ◽  
Vol 40 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Thomas V. Lowell ◽  
Dale A. Becker ◽  
Parker E. Calkin
Keyword(s):  
Subsequent Development ◽  
Drill Hole ◽  
Progress Report ◽  
Alluvial Fans ◽  
Ice Flow ◽  
Log Data ◽  
Sequence Of Events ◽  
Quaternary Stratigraphy ◽  
Early Portion ◽  
Late Wisconsinan

ABSTRACT A preliminary Quaternary stratigraphy for northwestern Maine can be assembled from interpretation of ice-flow indicators (dispersal and erosional), exposed sections, and drill-hole logs. Evidence from the ice-flow indicators delineates at least four regions each with different ice-flow histories. The distribution of these regions may result from an eastward invasion of Laurentide source ice during the early portion of the late Wisconsinan and subsequent development of a local ice dome during the closing portion of the Late Wisconsinan substage. Exposed sections contribute the following probable sequence of events to the stratigraphy: 1) deposition of alluvial fans, 2) deposition of a gray compact till beneath eastward flowing (Laurentide) ice, 3) deposition of a brown till beneath northward flowing local ice, 4) deglaciation by a southward retreating ice margin. These events appear continuous and have all been provisionally assigned a Late Wisconsinan age. Drill-hole logs confirm the sequence derived from the exposed sections and allow extension of the Quaternary stratigraphy. The drill-log data show three associated groups of sediments that may in turn result from at least three separate ice margin advances and recessions. The uppermost group of sediments is correlated with those found in exposed sections. The position of the drill-hole logs in an over-deepened basin suggest erosion by at least one even earlier glaciation.

Quaternary geology of the Babine porphyry copper district: implications for geochemical exploration

2001 ◽  
Vol 38 (4) ◽  
pp. 733-749 ◽  
Author(s):  
Victor M Levson
Keyword(s):  
Porphyry Copper ◽  
Clear Understanding ◽  
Dispersal Patterns ◽  
Ice Flow ◽  
Lake Region ◽  
Quaternary Stratigraphy ◽  
Glaciofluvial Deposits ◽  
Westerly Flow ◽  
Late Wisconsinan ◽  
Selection Of

The Quaternary stratigraphy of the Babine Lake region is characterized by a Late Wisconsinan succession of advance-phase glaciolacustrine sediments, glaciofluvial deposits, and till. Pollen data from a rare new interglacial site suggest a colder than present Middle Wisconsinan climate. Ice flow during the last glaciation was dominantly southeasterly, but in the Babine Range a regional, westerly ice-flow event occurred. Evidence for westerly flow diminishes eastward of Babine Lake, suggesting that the valley was near the eastward limit of an interior ice divide. Deglacial sediments include ice-marginal debris-flow, glaciofluvial, and glaciolacustrine sediments. Raised-delta elevations indicate that Glacial Lake Babine extended nearly 150 m above present lake level to 850 m asl, and higher, earlier phases may have existed locally. A variety of Holocene deposits cap the Quaternary succession. Glaciation has important implications for exploration in this copper-producing area. Southeasterly glacial dispersal patterns dominate, despite a regionally complex ice-flow history. Highly anomalous concentrations of copper occur in tills down-ice of most known bedrock copper occurrences, and a number of similarly anomalous till sites with no known copper sources have been identified in drift-covered areas. Exploration problems due to the thick and complex surficial cover can be overcome by selective sampling of basal tills, the composition of which clearly reflects the presence of buried mineral deposits. The effectiveness of till geochemistry as a method for locating buried mineralization in the region will be enhanced by careful selection of sample media and by a clear understanding of the glacial history.

scholarly journals Objective Reconstructions of the Late Wisconsinan Laurentide Ice Sheet and the Significance of Deformable Beds

2007 ◽  
Vol 39 (3) ◽  
pp. 229-238 ◽  
Author(s):  
D. A. Fisher ◽  
N. Reeh ◽  
K. Langley
Keyword(s):  
Yield Stress ◽  
Flow Direction ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Ice Streams ◽  
Ice Flow ◽  
Surface Slopes ◽  
Late Wisconsinan

ABSTRACT A three dimensional steady state plastic ice model; the present surface topography (on a 50 km grid); a recent concensus of the Late Wisconsinan maximum margin (PREST, 1984); and a simple map of ice yield stress are used to model the Laurentide Ice Sheet. A multi-domed, asymmetric reconstruction is computed without prior assumptions about flow lines. The effects of possible deforming beds are modelled by using the very low yield stress values suggested by MATHEWS (1974). Because of low yield stress (deforming beds) the model generates thin ice on the Prairies, Great Lakes area and, in one case, over Hudson Bay. Introduction of low yield stress (deformabie) regions also produces low surface slopes and abrupt ice flow direction changes. In certain circumstances large ice streams are generated along the boundaries between normal yield stress (non-deformable beds) and low yield stress ice (deformabie beds). Computer models are discussed in reference to the geologically-based reconstructions of SHILTS (1980) and DYKE ef al. (1982).

Landscapes of cold-centred Late Wisconsinan ice caps, Arctic Canada

1993 ◽  
Vol 17 (2) ◽  
pp. 223-247 ◽  
Author(s):  
Arthur S. Dyke
Keyword(s):  
Canadian Arctic ◽  
Thermal Conditions ◽  
Flow Patterns ◽  
Flow Conditions ◽  
Ice Flow ◽  
Zone Width ◽  
Ice Caps ◽  
Ice Cap ◽  
Late Wisconsinan ◽  
Subglacial Meltwater

Uplands of the Canadian Arctic Islands supported Late Wisconsinan ice caps that developed two landscape zones reflecting basal thermal conditions regulated by long-sustained ice flow patterns. Central cold-based zones protected older glacial and preglacial landscapes while peripheral warm-based zones scoured and otherwise altered their beds. Some geomorphic effects are independent of ice cap scale, others vary with scale. For ice caps of 30 km radius or more, scour-zone width remains proportionally constant to flowline length under similar flow conditions. But intensity of scouring, ice moulding of drift and rock eminences, size and abundance of subglacial meltwater features, and development of end moraines increase with ice cap size. Ice caps became entirely cold based early in retreat as the boundary between warm and cold ice shifted outward, probably because ice thinned and flow slackened. The frozen margins deflected meltwater, thus maximizing formation of lateral meltwater channels throughout retreat. The landform record of cold-based glaciers in this region is easily interpreted. Hence, regional ice sheet models invoking or based on the premise that cold-based ice leaves no geomorphic record seem untenable.

Late Quaternary glacial and interglacial environments of the Nechako River - Cheslatta Lake area, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 719-731 ◽  
Author(s):  
A Plouffe ◽  
V M Levson
Keyword(s):  
British Columbia ◽  
Late Quaternary ◽  
Late Glacial ◽  
Lake Area ◽  
Glacial Lakes ◽  
Ice Flow ◽  
Coast Mountains ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Quaternary History

The Quaternary stratigraphy of the Nechako River – Cheslatta Lake area of central British Columbia is described and interpreted to reconstruct the late Quaternary history of the region. Exposures of glacial and nonglacial sediments deposited prior to the last glaciation (Fraser) are limited to three sites. Pollen assemblages from pre-Fraser nonglacial sediments at two of these sites reveal forested conditions around 39 000 BP. During the advance phase of the Fraser Glaciation, glacial lakes were ponded when trunk glaciers blocked some tributary valleys. Early in the glaciation, the drainage was free in easterly draining valleys. Subsequently, the easterly drainage was blocked either locally by sediments and ice or as a result of impoundment of the Fraser River and its tributaries east of the study area. Ice generally moved east and northeast from accumulation zones in the Coast Mountains. Ice flow was influenced by topography. Major late-glacial lakes developed in the Nechako River valley and the Knewstubb Lake region because potential drainage routes were blocked by ice.

A reconstruction of glacial events in southeastern New Brunswick

1991 ◽  
Vol 28 (10) ◽  
pp. 1594-1612 ◽  
Author(s):  
Marc Foisy ◽  
Gilbert Prichonnet
Keyword(s):  
New Brunswick ◽  
Ice Flow ◽  
Ice Cap ◽  
The North ◽  
Lithostratigraphic Units ◽  
Glaciofluvial Deposits ◽  
Southern Border ◽  
Late Wisconsinan ◽  
Radial Outflow ◽  
North And South

Sedimentological and petrographical data obtained from five sections located north and south of the Caledonian Highlands in southeastern New Brunswick demonstrate the existence of three main till units and one glaciofluvial unit, which have been grouped in four distinct lithostratigraphic units. The lower till was deposited by a glacier that overrode the Caledonian Highlands from northwest to southeast and advanced as far as Nova Scotia during Middle(?) to Late Wisconsinan times. The overlying middle till from the north provides evidence that ice continued to advance across the Highlands from northwest toward southeast and then was partially overwhelmed by another glacier that was advancing southwest along the southern border of the Highlands: this glacier deposited a coeval middle till. During Late Wisconsinan deglaciation, ice separated into two masses: a residual ice cap with radial outflow from the Highlands; and a lobe in the Chignecto Bay, retreating toward the northeast. The existence of a plateau ice cap is demonstrated by the presence of till and glaciofluvial deposits in the upper part of all surveyed sections, and is supported by the sequence of ice flow patterns recorded by striae and the centrifugal distribution of meltwater flow indicators. The weak development of soils, the fresh appearance of till and morainic landforms, and the lack of periglacial features throughout the area, especially on the Highlands, all favour the interpretation that the Caledonian Highlands were not a nunatak during the glacial maximum of the Late Wisconsinan Substage.

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.

Influence of bedrock geology on sedimentation in Pre-Late Wisconsinan alluvial fans in the Canadian Rocky Mountains

2000 ◽  
Vol 68-71 ◽  
pp. 133-146 ◽  
Author(s):  
Victor M Levson ◽  
Nathaniel W Rutter
Keyword(s):  
Rocky Mountains ◽  
Alluvial Fans ◽  
Canadian Rocky Mountains ◽  
Bedrock Geology ◽  
Late Wisconsinan

scholarly journals Subglacial drainage processes at a High Arctic polythermal valley glacier

2005 ◽  
Vol 51 (172) ◽  
pp. 15-24 ◽  
Author(s):  
Robert G. Bingham ◽  
Peter W. Nienow ◽  
Martin J. Sharp ◽  
Sarah Boon
Keyword(s):  
Drainage System ◽  
Structural Evolution ◽  
Subsequent Development ◽  
High Arctic ◽  
Breakthrough Curves ◽  
Ice Flow ◽  
Dye Tracer ◽  
Arctic Glacier ◽  
Tracer Experiments ◽  
Subglacial Drainage

AbstractDye-tracer experiments undertaken over two summer melt seasons at polythermal John Evans Glacier, Ellesmere Island, Canada, were designed to investigate the character of the subglacial drainage system and its evolution over a melt season. In both summers, dye injections were conducted at several moulins and traced to a single subglacial outflow. Tracer breakthrough curves suggest that supraglacial meltwater initially encounters a distributed subglacial drainage system in late June. The subsequent development and maintenance of a channelled subglacial network are dependent upon sustained high rates of surface melting maintaining high supraglacial inputs. In a consistently warm summer (2000), subglacial drainage became rapidly and persistently channelled. In a cooler summer (2001), distributed subglacial drainage predominated. These observations confirm that supraglacial meltwater can access the bed of a High Arctic glacier in summer, and induce significant structural evolution of the subglacial drainage system. They do not support the view that subglacial drainage systems beneath polythermal glaciers are always poorly developed. They do suggest that the effects on ice flow of surface water penetration to the bed of predominantly cold glaciers may be short-lived.

scholarly journals Wisconsinan Inter-Lobal Stratigraphy in Three Quarries Near Woodstock, Ontario

2002 ◽  
Vol 55 (1) ◽  
pp. 3-22 ◽  
Author(s):  
Dariusz Krzyszkowski ◽  
P. F. Karrow
Keyword(s):  
Grain Size ◽  
Ice Flow ◽  
Glacial Sediment ◽  
Color Structure ◽  
Limestone Quarries ◽  
Late Wisconsinan

Abstract The Huron-Erie interlobate zone passes near Woodstock, Ontario. Three large limestone quarries (Zorra, Beachville West, Beachville East) provide exposures up to 30 m high of the drift stratigraphy. Grain size, matrix carbonate, color, structure, fabric, lithology, and sequence, along with continuous tracing of contacts and facies changes, allowed recognition of ten tills and related water-laid sediments correlated with the known stratigraphy in surrounding areas.Four major glacial events are recognized, three of Late Wisconsinan age. Three tongues of red, Erie lobe Canning Till (unknown age) are over-lain by a Nissouri Stadial (22-17 ka) Catfish Creek Drift complex (two till tongues, regional southwest ice flow). Similar, apparently correlative, glacial and non-glacial sediment sequences within Catfish Creek Drift at Zorra and Beachville West (Centreville Member) suggest a northwest-southeast-trending ice margin. Overlying this are Erie Interstadial (16 ka) glaciolacustrine sediments (Rayside beds), Port Bruce Stadial (15-14 ka) Erie lobe Port Stanley Till, glaciolacustrine Zorra beds, and final Port Bruce Stadial Huron lobe Tavistock Till (three tongues), and deglacial out-wash (Dunn's Corner gravels). Repeated glaciolacustrine sedimentation between tills may relate to glacioisostatically reduced gradients and nearby ice lobe margins. There is little evidence of Catfish Creek interlobate conditions and only independent lobal glacial advances later.

The Drift des Demoiselles on the Magdalen Islands (Québec, Canada): sedimentological and micromorphological evidence of a Late Wisconsinan glacial diamict

2013 ◽  
Vol 50 (5) ◽  
pp. 545-563 ◽  
Author(s):  
Audrey M. Rémillard ◽  
Bernard Hétu ◽  
Pascal Bernatchez ◽  
Pascal Bertran
Keyword(s):  
Sea Level ◽  
Ice Flow ◽  
Glacial Deposit ◽  
Marine Transgression ◽  
Deformation Structures ◽  
Ice Cap ◽  
Ice Wedge ◽  
Late Wisconsinan ◽  
Different Origin ◽  
Magdalen Islands

The deposits identified as being the Drift des Demoiselles, which is the upper unit of the southern Magdalen Islands (Québec, Canada), belong to two units of different origin, glacial and glaciomarine. At Anse à la Cabane, the glacial deposit comprises two subunits: a glacitectonite at the base and a subglacial traction till at the top. Numerous glaciotectonic deformation structures suggest ice flow towards the southeast. The till is above an organic horizon dated to ∼47–50 ka BP. New data presented here show that the southern part of the Magdalen archipelago was glaciated during the Late Wisconsinan. We relate this ice flow to the Escuminac ice cap, whose centre of dispersion was located in the Gulf of St. Lawrence, northwest of the islands. At Anse au Plâtre, the top of the Drift des Demoiselles is a glaciomarine deposit. At Anse à la Cabane, the till is covered by a stratified subtidal unit located at ∼20 m above sea level. Both were deposited during the marine transgression that followed deglaciation. At Anse à la Cabane, three ice-wedge casts truncate the till and the subtidal unit, providing evidence that periglacial conditions occurred on the archipelago after deglaciation.

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