Hudson Bay river sediments and regional glaciation: III. Implications of mineralogical studies for Wisconsinan and earlier ice-flow patterns

1983 ◽  
Vol 20 (2) ◽  
pp. 313-321 ◽  
Author(s):  
J. D. Adshead
Keyword(s):  
River Sediments ◽  
Flow Patterns ◽  
Hudson Bay ◽  
James Bay ◽  
Dispersal Patterns ◽  
Regional Patterns ◽  
Ice Flow ◽  
Fluvial Sediment ◽  
Sediment Data ◽  
James Bay Lowlands

Mineralogical studies of river sediments from the Hudson Bay and James Bay Lowlands suggest that the glacial erosion of pre-Devonian Paleozoic carbonate rocks played an important role in the production of calcite-enriched debris in the Cape Henrietta Maria watershed. Ice flowing southwesterly across Devonian basins in western Hudson Bay and the James Bay Lowlands would largely bypass the intervening cape area.Enrichment of iron in river sands of the cape watershed is attributed to Proterozoic ferruginous sources now largely submerged under the waters of eastern Hudson Bay. Distributional patterns of carbonates and iron indicate that the dominant flow of ice from eastern Hudson Bay was southwesterly toward Cape Henrietta Maria, without major flow from the area of Proterozoic bedrock into the Nelson River watershed. In the cape area, iron enrichment due to Proterozoic sources significantly overshadows possible contributions from siderite-bearing Devonian bedrock.The fluvial sediment data are consistent with a multiple dome model of glaciation with ice mass centres located east and west of Hudson Bay. However, quartz/(total carbonate) ratios indicate that, if independent ice masses existed in this configuration, the dominant position of their contact should be placed north of the Churchill–Nelson watershed boundary. Indications of K-feldspar enrichment in Churchill sands are not evident in cape localities where ice flow was southwesterly.Rivers sands are composite channel samples of a drift cover that includes several pre-Wisconsinan tills as well as Wisconsinan deposits. Well defined regional patterns of composite (fluvial) sediment composition suggest a consistency in dominant regional ice movements through time. Similarities between regional drift dispersal limits based on these composite sediments and on pebble dispersal patterns for Wisconsinan tills further indicate that dominant ice-flow patterns in central Canada were probably similar for Wisconsinan and earlier glaciations.

Hudson Bay river sediments and regional glaciation: I. Iron and carbonate dispersal trains southwest of Hudson and James Bays

1983 ◽  
Vol 20 (2) ◽  
pp. 290-304 ◽  
Author(s):  
J. D. Adshead
Keyword(s):  
Iron Content ◽  
River Sediments ◽  
Hudson Bay ◽  
Sand Fraction ◽  
Ice Flow ◽  
Iron Enrichment ◽  
Dominant Pattern ◽  
Carbonate Composition ◽  
North And South

Sands deposited from rivers draining the southwesterly trending watershed of the Cape Henrietta Maria area are enriched in calcite and are characterized by higher calcite/dolomite ratios than the sands from rivers north and south of the cape. This pattern suggests that a train of drift with distinctive carbonate composition extends southwest of Cape Henrietta Maria, indicating a dominant pattern of southwesterly ice flow in this region.Iron contents are highest for sands from rivers on Cape Henrietta Maria, suggesting iron enrichment in the sand fraction of tills in the cape area, and the existence of a broad dispersal train extending southwest of the cape. The dispersal train inferred from the calcite/dolomite ratios overprints part, but not all, of the dispersal train inferred from the iron content.

Southeastward ice flow in central Quebec and its paleogeographic significance

1985 ◽  
Vol 22 (10) ◽  
pp. 1536-1541 ◽  
Author(s):  
Michel A. Bouchard ◽  
Ghismond Martineau
Keyword(s):  
Hudson Bay ◽  
East Side ◽  
James Bay ◽  
Rock Outcrops ◽  
Ice Flow ◽  
West Central

Directional glacial erosional marks located systematically on the southwest side of rock outcrops in the Chibougamau and Lac Mistassini areas in west-central Quebec indicate unequivocally a sustained regional event of southeast ice flow prior to the last or regional southwest flow from New Quebec. Striations from the former ice flow are consistently oriented at around 120° azimuth and are observed, albeit at scattered occurrences, within an area covering thousands of square kilometres. Although the age of the southeast ice flow event cannot be determined, it is considered more likely to be of Wisconsinan age on the basis of the well preserved state of its features and the lack of deep weathering on surfaces where these are observed. It is suggested that the early ice flow event might have been fed by a local outflow centre on the east side of James Bay, perhaps extending as a ridge east of Hudson Bay.

scholarly journals Laurentide Ice-Flow Patterns: A Historical Review, and Implications of the Dispersal of Belcher Islands Erratics

2007 ◽  
Vol 44 (2) ◽  
pp. 113-136 ◽  
Author(s):  
Victor K. Prest
Keyword(s):  
Ice Sheet ◽  
Historical Review ◽  
Flow Patterns ◽  
The Arctic ◽  
Laurentide Ice Sheet ◽  
Complex Nature ◽  
Hudson Bay ◽  
Ice Flow ◽  
Flow Models ◽  
The North

ABSTRACTThis paper deals with the evolution of ideas concerning the configuration of flow patterns of the great inland ice sheets east of the Cordillera. The interpretations of overall extent of Laurentide ice have changed little in a century (except in the Arctic) but the manner of growth, centres of outflow, and ice-flow patterns, remain somewhat controversial. Present geological data however, clearly favour the notion of multiple centres of ice flow. The first map of the extent of the North American ice cover was published in 1881. A multi-domed concept of the ice sheet was illustrated in an 1894 sketch-map of radial flow from dispersal areas east and west of Hudson Bay. The first large format glacial map of North America was published in 1913. The binary concept of the ice sheet was in vogue until 1943 when a single centre in Hudson Bay was proposed, based on the westward growth of ice from Labrador/Québec. This Hudson dome concept persisted but was not illustrated until 1977. By this time it was evident from dispersal studies that the single dome concept was not viable. Dispersal studies clearly indicate long-continued westward ice flow from Québec into and across southern Hudson Bay, as well as eastward flow from Keewatin into the northern part of the bay. Computer-type modelling of the Laurentide ice sheet(s) further indicates their complex nature. The distribution of two indicator erratics from the Proterozoicage Belcher Island Fold Belt Group help constrain ice flow models. These erratics have been dispersed widely to the west, southwest and south by the Labrador Sector of more than one Laurentide ice sheet. They are abundant across the Paleozoic terrain of the Hudson-James Bay lowland, but decrease in abundance across the adjoining Archean upland. Similar erratics are common in northern Manitoba in the zone of confluence between Labrador and Keewatin Sector ice. Scattered occurences across the Prairies occur within the realm of south-flowing Keewatin ice. As these erratics are not known, and presumably not present, in Keewatin, they indicate redirection and deposition by Keewatin ice following one or more older advances of Labrador ice. The distribution of indicator erratics thus test our concepts of ice sheet growth.

Extractable organic fractions of podzolic and associated soils in the Hudson Bay-James Bay Lowlands

Geoderma ◽  
1988 ◽  
Vol 41 (3-4) ◽  
pp. 263-274 ◽  
Author(s):  
P.A Schuppli ◽  
R Protz ◽  
J.A McKeague
Keyword(s):  
Hudson Bay ◽  
James Bay ◽  
Organic Fractions ◽  
James Bay Lowlands

Carbonate till as a soft bed for Pleistocene ice streams on the Canadian Shield north of Lake Superior

1989 ◽  
Vol 26 (11) ◽  
pp. 2249-2254 ◽  
Author(s):  
Stephen R. Hicock ◽  
Fridrik J. Kristjansson ◽  
David R. Sharpe
Keyword(s):  
Thickness Distribution ◽  
Lake Superior ◽  
Canadian Shield ◽  
Shear Stresses ◽  
Hudson Bay ◽  
Ice Streams ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Ice Flow ◽  
Basal Shear

Silty carbonate till derived from erosion of Paleozoic carbonate and Proterozoic rocks within and adjacent to Hudson Bay covers extensive areas of the Canadian Shield north of Lake Superior. It is hypothesized that this carbonate till could have acted as low-resistance substrata for overriding ice streams by deforming and (or) supporting high subglacial water pressures. Contrary to assumptions presented in some current models for ice flow within the Laurentide Ice Sheet, it need not be assumed that Shield terrain in these areas acted as a rigid bed, generating large basal shear stresses and inhibiting ice flow. Indeed, erratic-dispersal patterns, long-distance glacial transport, and splayed patterns of ice-flow indicators in areas of thick till cover may be better explained by rapid ice-flow events or ice streams, enhanced by the thickness, distribution, impermeability, and susceptibility to deformation of fine carbonate till.

Hudson Bay river sediments and regional glaciation: II. Comparison of carbonate mineralogy of size fractions for ice movement inference

1983 ◽  
Vol 20 (2) ◽  
pp. 305-312 ◽  
Author(s):  
J. D. Adshead
Keyword(s):  
River Sediments ◽  
Regional Distribution ◽  
Hudson Bay ◽  
Primary Control ◽  
Coarse Silt ◽  
Fine Silt ◽  
Ice Flow ◽  
Size Fractions ◽  
Size Grade ◽  
Original Crystal

Comparison of the carbonate mineralogy of sand, coarse silt, fine silt, and coarse clay fractions of river sediments from the Hudson Bay region demonstrates that dolomite is more abundant than calcite in the coarse silts but is less abundant than calcite in other size fractions. In coarse silts, dolomite commonly occurs as single crystals in the shape of well defined rhombs, whereas calcite is present as equant to subequant grains (few rhomb-shaped crystals). Dolomite grains appear to have greater resistance to abrasion than calcite grains after particles have been reduced to sizes lying in the coarse silt range. Although differing physical properties may play a role, it appears likely that the primary control on the particle size distributions of the carbonate minerals is their original crystal size in the source bedrock.The calcite/dolomite ratio for dolomite-enriched coarse silt parallels the regional distribution observed for sand, fine silt, and coarse clay, with highest values occurring in the Cape Henrietta Maria area. Carbonate mineral ratios for silt and clay fractions corroborate the results obtained for sands and provide further evidence for the existence of a carbonate dispersal train extending southwest of the cape. These results further demonstrate that fluvial carbonates can be useful indicators of regional drift dispersal and ice-flow patterns.The widespread use of silt or combined silt and clay fractions for calcite and dolomite determinations in drift provenance studies is not upheld by the results of this investigation. Coarse silts, which have been enriched in dolomite due to abrasion processes, provide a substantially distorted interpretation of source bedrock composition. Use of the sand-size grade is advocated. Sands, unlike coarse silts, reflect the major occurrence of limestones and minor dolostones in Paleozoic basins of the region.

Ice-flow patterns and dispersal of erratics at the southwestern margin of the last Scandinavian Ice Sheet: signature of palaeo-ice streams

Boreas ◽  
2003 ◽  
Vol 32 (1) ◽  
pp. 130-148 ◽  
Author(s):  
KURT H. KJÆR ◽  
MICHAEL HOUMARK-NIELSEN ◽  
NIELS RICHARDT
Keyword(s):  
Ice Sheet ◽  
Flow Patterns ◽  
Ice Streams ◽  
Ice Flow ◽  
Scandinavian Ice Sheet ◽  
Southwestern Margin

Morphological and isozyme variation in Salicornia europaea (s.l.) (Chenopodiaceae) in northeastern North America

1987 ◽  
Vol 65 (7) ◽  
pp. 1410-1419 ◽  
Author(s):  
S. L. Wolff ◽  
R. L. Jefferies
Keyword(s):  
North America ◽  
Atlantic Coast ◽  
Hudson Bay ◽  
Salicornia Europaea ◽  
Electrophoretic Variation ◽  
James Bay ◽  
Northeastern North America ◽  
Electrophoretic Patterns ◽  
Anther Length ◽  
Vegetative Characters

Morphological and electrophoretic variation has been documented within and among populations of Salicornia europaea L. (s.l.) in northeastern North America. Univariate and multivariate analyses (discriminant analyses) of measurements of floral and vegetative characters delimited three morphologically distinct groups of populations: Atlantic coast tetraploids (2n = 36), Hudson Bay diploids, and Atlantic coast and James Bay diploids (2n = 18). The two diploid groups were morphologically distinct from the midwestern diploid, S. rubra Nels., based on anther length, width of the scarious border of the fertile segment, and the overall width of the fertile segment. Electrophoretic evidence supported the delimitation of the three distinct morphological groups of populations of S. europaea with the exception of the population from James Bay, which had electrophoretic patterns identical with those of plants from Hudson Bay but resembled the Atlantic coast diploids morphologically. Most enzyme systems assayed were monomorphic. Only homozygous banding patterns were detected in diploid plants and electrophoretic variation was not observed within populations of S. europaea or S. rubra but was detected between groups of populations. Four multilocus phenotypes were evident; these corresponded to the major groups recognized on the basis of ploidy level and morphology. Reasons that may account for the paucity of isozymic variation are discussed.

Till sedimentology and stratigraphy on the Dingle Peninsula, SW Ireland: implications for Late Quaternary regional ice flow patterns

2008 ◽  
Vol 119 (2) ◽  
pp. 137-152 ◽  
Author(s):  
Colm Ó Cofaigh ◽  
David J.A. Evans ◽  
John Hiemstra
Keyword(s):  
Late Quaternary ◽  
Flow Patterns ◽  
Ice Flow

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).

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