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.

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.

scholarly journals Total mercury distribution among soil aggregate size fractions in a temperate forest podzol

2018 ◽  
Vol 8 ◽  
Author(s):  
Antía Gómez Armesto ◽  
Lucía Bibián-Núñez ◽  
Claudia Campillo-Cora ◽  
Xabier Pontevedra-Pombal ◽  
Manuel Arias-Estévez ◽  
...  
Keyword(s):  
Temperate Forest ◽  
Aggregate Size ◽  
Fine Sand ◽  
Soil Aggregate ◽  
Coarse Sand ◽  
Coarse Silt ◽  
Fine Silt ◽  
Size Fractions ◽  
Total Hg ◽  
Sand Size

This study determined the distribution of total Hg (Hg<sub>T</sub>) among aggregate size fractions in the A, E, Bh and Bs horizons of a representative temperate forest podzol. The aggregate distribution was dominated by the coarse sand size fraction (average of 55%) followed by fine sand (29%), fine silt (10%), coarse silt (4%) and clay (2%). In general, Hg<sub>T</sub> mean values increased as the aggregate size become smaller: clay (170 ng g<sup>-1</sup>) &gt; fine silt (130 ng g<sup>-1</sup>) &gt; coarse silt (80 ng g<sup>-1</sup>) &gt; fine sand (32 ng g<sup>-1</sup>) &gt; coarse sand (14 ng g<sup>-1</sup>). Total Hg enrichment in clay-sized aggregates ranged from 2 to 11 times higher than the values shown by the bulk soil (&lt; 2 mm). The accumulation of Hg<sub>T</sub> in the finer size aggregates was closely related to total organic C, Na-pyrophosphate extracted C, metal (Al, Fe)-humus complexes and Al and Fe oxyhydroxides. Indeed, these parameters varied significantly (<em>p </em>&lt; 0.05) with the aggregate size and their highest values were found in the finer fractions. This suggested the role of these soil compounds in the increase of the specific surface area per mass unit and negative charges in the smallest aggregates, favouring Hg retention. Mercury accumulation factor (Hg<sub>AF</sub>) values reached up to 10.8 in the clay size aggregates, being close to 1 in sand size fractions. Regarding Hg enrichment factors (Hg<sub>EF</sub>), they were &lt; 4 (“moderate pollution” category) in most of the horizons and aggregate sizes. Grain size mass loading (GSF<sub>Hg</sub>) revealed that finer fractions had a higher Hg loading than their mass fractions, with a notable contribution of fine silt which made up &gt; 50% of Hg<sub>T</sub> in Bh and Bs horizons. The potential ecological risk index (PERI<sub>Hg</sub>) increased as the aggregate size decreased, with the highest values in the illuvial horizons (45-903) and lowest in the E horizon (3-363). Heterogeneous distribution of Hg in the soil aggregate size fractions must be considered for Hg determination for purposes such as critical loads, background values or environmental risk indices. In addition, Hg accumulation in finer aggregates could be of concern due to its potential mobility in forest soils, either transferred by leaching to groundwater and freshwaters or mobilized by runoff in surface horizons.

Ice-flow patterns and glacial transport in the eastern Hudson Bay region: implications for the late Quaternary dynamics of the Laurentide Ice Sheet

1995 ◽  
Vol 32 (12) ◽  
pp. 2057-2070 ◽  
Author(s):  
Michel Parent ◽  
Serge J. Paradis ◽  
Éric Boisvert
Keyword(s):  
Compositional Data ◽  
Late Quaternary ◽  
Regional Distribution ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Ice Flow ◽  
Flow Phase ◽  
Late Wisconsinan

Recent field surveys in the eastern Hudson Bay region have led to the discovery of regional ice-flow sequences that require a significant reassessment of the late Quaternary dynamics of the Laurentide Ice Sheet. Two regional ice-flow phases can be recognized from till compositional data and from crosscutting relationships observed on striated bedrock surfaces: the oldest is directed toward the northwest and north-northwest, while the youngest is directed toward the west and includes a late-glacial deflection toward the southwest. The wide regional distribution of striae formed during the early northwestward glacial movement together with the recognition of palimpsest glacial dispersal trains associated with this phase suggest that it was a long-lived, time-transgressive regional event. The ensuing glacial movement is a regionally dominant westward ice-flow phase during which several large glacial dispersal trains were formed downglacier from distinctive bedrock sources. The largest of these trains extends westward over a distance of 120 km from Lac à l'Eau Claire to Hudson Bay. Regional glacial transport data as well as glacial and deglacial landforms indicate that this was a long-lived glacial phase, likely lasting throughout the Late Wisconsinan glacial maximum and until déglaciation about 8000 BP. The erosional and depositional record of the northwestward ice-flow event is quite comparable to that of the ensuing glacial phase, and it is thus thought to represent the Early Wisconsinan glacial maximum. In view of the large regional extent of the northwestward ice-flow phase, it must postdate the early buildup of the ice sheet. Along the southeastern Hudson Bay coast, the Late Wisconsinan westward glacial movement was followed by a southwestward deflection that was likely caused by glacial streaming prior to 8000 BP in James Bay, in response to calving and surging into Glacial Lake Ojibway.

scholarly journals Particle size partitioning of metals in humus horizons of two small erosional landforms in the middle Protva basin – a comparative study

2020 ◽  
Vol 13 (1) ◽  
pp. 260-271 ◽  
Author(s):  
Olga A. Samonova ◽  
Elena N. Aseyeva
Keyword(s):  
Particle Size ◽  
Mixed Forest ◽  
Coarse Sand ◽  
Particle Sizes ◽  
Coarse Silt ◽  
Fine Silt ◽  
Forest Zone ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Humus Horizons

Partitioning of metals in soil particles of various size classes has been receiving greater significance due to the necessity to predict the behaviour and pathways of the potentially toxic elements in the environment. In this study the analysis of metals’ distribution in various particle size fractions was performed to characterize and compare geochemical features of the topsoil horizons of two small erosional landforms located in uncontaminated area of the central part of European Russia (the Middle Protva basin, mixed forest zone). The landforms represent two typical lithological types of gullies in the study area. Soil samples were fractionated and the concentrations of Fe, Mn, Ti, Zr, Ni, Co, Cr, Zn, Cu, Pb were determined in five particle size fractions: 1–0.25, 0.25-0.05, 0.05−0.01, 0.01–0.001 and <0.001 mm. The metals’ concentrations and their distribution in various particle sizes were found to be related to gully litho-type. The contribution of the clay to the total amount of metals was the greatest for Mn, Zn, Ni and Co in both systems. The highest mass loading for Ti, Zr and Cr came from the coarse silt, while for Cu and Pb it was made by different particle size fractions: the medium and fine silt or the coarse silt. The highest contribution of Fe also came from different fractions, either from the coarse sand or the clay depending on the system.

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.

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).

The plastic limit of silty, surface soils in relation to their content of polysaccharide gel

Soil Research ◽  
1995 ◽  
Vol 33 (1) ◽  
pp. 1 ◽  
Author(s):  
WW Emerson
Keyword(s):  
Plastic Limit ◽  
Coarse Silt ◽  
Surface Soils ◽  
Fine Silt ◽  
The Matrix ◽  
Clay Matrix ◽  
Matrix Suction ◽  
Constant Percentage

By using values reported in the literature, the plastic limits of mainly silty surface soils have been found to increase by 6-7 g H2O per g of C present. To explain this, it is suggested that at the plastic limit, particles of coarse silt are being rolled over each other with compacted portions of fine silt/clay matrix in between. The plastic limit is increased because of water sorbed by bonding polysaccharide gels in additional 1-3 �m sized pores between the compacted portions. The presence of such pores should have little effect on the matrix suction since this is determined by the size of the largest water-filled pores present. Water sorbed will then be proportional to C content as found, provided the composition of the polysaccharides present is constant and polysaccharide C forms a constant percentage of total C. This allows changes in the plastic limit of a soil to be used to indicate relative amounts of gel present. For example, several years after cropping was changed from grass to arable, more gel was present than in the same soils under continuous arable. Mild peroxidation of one soil did not alter the proportion of the total C present in gel form.

Geochemical investigations in bulk and clay size fractions from lower Krishna river sediments, southern India: implications of elemental fractionation during weathering, transportation and deposition

2019 ◽  
Vol 23 (6) ◽  
pp. 951-960 ◽  
Author(s):  
Archana Bhagwat Kaotekwar ◽  
Syed Masood Ahmad ◽  
Manavalan Satyanarayanan ◽  
Aradhi Keshav Krishna
Keyword(s):  
River Sediments ◽  
Southern India ◽  
Elemental Fractionation ◽  
Size Fractions

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.

A woolly mammoth (Proboscidea, Mammuthus primigenius) molar from the Hudson Bay Lowland of Manitoba

1988 ◽  
Vol 25 (6) ◽  
pp. 933-938 ◽  
Author(s):  
Erik Nielsen ◽  
C. S. Churcher ◽  
G. E. Lammers
Keyword(s):  
Depositional Environment ◽  
River Sediments ◽  
Hudson Bay ◽  
Tree Line ◽  
Mammuthus Primigenius ◽  
Early Form ◽  
Enamel Thickness ◽  
Hudson Bay Lowland ◽  
Woolly Mammoth

The first fossil mammal from the Hudson Bay Lowland of Manitoba, a molar from the woolly or Siberian mammoth, Mammuthus primigenius, is described from near Bird. A lophar index of 9.0 and an enamel thickness of 1.5–2.3 mm allow the tooth to be assigned to an early form of the species. Although in situ provenance of the molar is unknown, it is likely that the molar derives from Early Wisconsinan or Sangamon sediments that outcrop in the area. A boreal steppe or steppe–tundra environment is indicated by the presence of woolly mammoth, supporting a depositional environment north of the then tree line previously established for the Nelson River sediments.

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