Stephen R. Moran

Huron (France)

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Quaternary Stratigraphy and History In the Southern Part of the Lake Agassiz Basin

M.M. Fenton Stephen R. Moran James T. Teller Lee Clayton

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Citations (95)

Hydrologic impacts of surface mining of coal in western North Dakota

Univ. Ky., Off. Eng. Serv., (Bull.); (United States) (1979)

Stephen R. Moran J.A. Cherry G. W. Rehm G.H. Groenewold

Three potential hydrologic impacts of surface mining, (1) transient water-level drawdown in wells outside the mining area, (2) development of a post-mining water supply, and (3) impact of mining and reclamation on water quality, have been evaluated in western North Dakota. Limited observational evidence confirms analytical projections of potential drawdown at two sites, which suggest that transient water-level declines adjacent to mine areas will be minor. Water-level declines of as much as 1 m are expected to be extremely unlikely beyond 2 km from active excavations. The presence of the major, regionally extensive Fox Hills-lower Hell Creek aquifer at depths ranging from 350 to 500 m provide a potential post-mining water supply for large users. Other coal and sand aquifers that are capable of providing smaller but adequate rural water supplies underlie most sites within 50 to 100 m of mineable coal beds. Although groundwater chemistry in cast overburden at some sites is little different from that prior to mining, solution of salts and acceleration of natural weathering at most sites produces calcium sulfate type groundwater with TDS values as much as 5 times as great as prior to mining. On the basis of preliminary analyses it appears that highlymore » saline water in cast overburden can produce a significant deterioration of water quality in surface streams in the vicinity of mine areas.« less

Overburden

Surface mining

Drawdown (hydrology)

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Citations (2)

The hydrologic response of aquifers at surface-mine sites in western North Dakota

Canadian Geotechnical Journal (1981)

Stephen R. Moran John A. Cherry

The excavation of mine pits in western North Dakota causes groundwater to flow laterally through the moderately to highly permeable fractured coal beds into the pits. Because of the low fracture-controlled storativity of the coal, the lateral flow results in rapid spread of a dewatered zone in the coal. The coal is generally overlain by saturated silty or clayey aquitards or fine sand that provide downward leakage to the coal. Existing analytical solutions for analysis of the problem of water-level decline and seepage flux are based on such extensive simplifying assumptions that they are a poor approximation of the field conditions. Numerical models for layered systems with transient saturated and unsaturated zones require efforts in analysis that are generally unwarranted relative to the nature of the field information. As an alternative to these approaches we applied a method based on existing analytical solutions with empirical adjustments to account for the effect of leakage. Results obtained using a programable pocket calculator indicating that, for areas for which mining is proposed, steady-state water levels in the coal will be rapidly attained as downward leakage through the overlying beds supplies all of the water maintaining the lateral flow regime in the coal.Predictions from analyses using representative values of hydraulic parameters for two mine sites indicate that significant declines in water levels adjacent to the mines will likely be restricted to within about 3 km of the highwall.

10.1139/t81-065

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Citations (4)

Chronology of late wisconsinan glaciation in middle North America

Quaternary Science Reviews (1984)

Stephen R. Moran Lee Clayton

Chronology

Wisconsin glaciation

10.1016/0277-3791(84)90018-0

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Citations (11)

Glacier-Bed Landforms of the Prairie Region of North America

Journal of Glaciology (1979)

Stephen R. Moran Lee Clayton R. Leb Hooke M.M. Fenton L.D. Andriashek

Abstract Two major types of terrain that formed at or near the bed of Pleistocene continental ice sheets are widespread throughout the prairie region of Canada and the United States. These are (1) glacial-thrust blocks and source depressions and (2) streamlined terrain. Glacial-thrust terrain formed where the glacier was frozen to the substrate and where elevated pore-water pressure decreased the shear strength of the substrate to a value less than that applied by the glacier. The marginal zone of ice sheets consisted of a frozen-bed zone, no more than 2 to 3 km wide in places, within which glacial-thrust blocks are large and angular. Up-glacier from this zone the thrust blocks are generally smaller and smoothed. Streamlined terrain begins 2 to 3 km behind known ice-margin positions and extends tens of kilometres up-glacier. Streamlined terrain formed in two ways: (1) erosion of the substrate as a consequence of basal sliding in the sub-marginal thawed-bed zone and (2) erosional smoothing accompanied by emplacement of till in the lee of thrust blocks where they were deposited and subsequently exposed to thawed-bed conditions as a result of further advance of the glacier. This paper has been accepted for publication in full in a future issue of the Journal of Glaciology .

Landform

Glacier morphology

10.1017/s0022143000030161

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Citations (128)

Groundwater hydrologic regimes within reclaimed surface coal mined landscapes in Alberta

Reclamation Sciences (1989)

Stephen R. Moran Mark R. Trudell T. M. Macyk

Between 1979 and 1988, the Plains Hydrology and Reclamation Project (PHRP) investigated interactions of groundwater, soils, and geology and successful reclamation of surface coal mines in the plains of Alberta.Among the objectives of the study was to document the processes by which a steady-state hydrologic regime was re-established following reclamation and to determine the rate at which steady-state conditions were attained.Instrumentation was installed in spoil at two study areas: the Battle River area, which included Diplomat, Vesta and Paintearth Mines, and the Wabamun area, which included the Highvale and Whitewood Mines.Our work demonstrated that the processes by which water enters the spoil and the rate at which the post-reclamation steady-state equilibrium hydrologic regime is established differ both within and beb,een mine sites depending on the hydraulic conductivity of the spoil and the landscape setting within the reclaimed terrain.In lowland settings at mines characterized by high penneability spoil, steady-state equilibrium conditions are established within 5 to 10 years of regrading.In upland settings at mines characterized by low penneability spoil, on the other hand, many decades are required to establish steady-state equilibrium conditions.

10.21000/jasmr89010209

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Citations (0)

Glacier-Bed Landforms of The Prairie Region of North America

Journal of Glaciology (1980)

Stephen R. Moran Lee Clayton R. Leb Hooke M.M. Fenton L.D. Andriashek

Abstract Two major types of terrain that formed at or near the bed of Pleistocene continental ice sheets are widespread throughout the prairie region of Canada and the United States. These are (1) glacial-thrust blocks and source depressions, and (2) streamlined terrain. Glacial-thrust terrain formed where the glacier was frozen to the substrate and where elevated pore-pressure decreased the shear strength of the substrate to a value less than that applied by the glacier. The marginal zone of ice sheets consisted of a frozen-bed zone, no more than 2–3 km wide in places, within which glacial-thrust blocks are large and angular. Up-glacier from this zone, the thrust blocks are generally smaller and smoothed. Streamlined terrain begins 2–3 km behind known ice-margin positions and extends tens of kilometres up-glacier Streamlined terrain formed in two ways: (1) erosion of the substrate as a consequence of basal sliding in the sub-marginal thawed-bed zone, and (2) erosional smoothing accompanied by emplacement of till in the lee of thrust blocks where they were deposited and subsequently exposed to thawed-bed conditions as a result of further advance of the glacier.

Landform

Glacier morphology

10.3189/s0022143000015306

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Citations (34)

The Wisconsinan deglaciation of southern Saskatchewan and adjacent areas: Discussion

Canadian Journal of Earth Sciences (1980)

James T. Teller Stephen R. Moran Lee Clayton

In his recently published paper summarizing the stratigraphic and morphologic record of southern Saskatchewan and adjacent areas, Christiansen (1979) proposed a chronology of deglaciation that is in error because it fails to integrate relevant data from outside of Saskatchewan. Christiansen's interpretation shows a progressive northward retreat of the glacial margin from Montana and North Dakota beginning before 16 000 years BP. By 15 500 years ago, the ice is shown to have retreated north of the Missouri River watershed (which previously had channelled all meltwater well south of the glaciated region) with runoff discharging eastward into Manitoba via the Souris and Pembina channels (Phase 3, Fig. 12 in Christiansen). At 14 000 years BP (Phase 4, Fig. 13), the glacial margin of Christiansen has retreated still farther north, with icefree conditions having developed over most of southern Saskatchewan; all rivers of the deglaciated region of Saskatchewan and Alberta are shown draining eastward into Lake Agassiz in Manitoba. The 14 000 year BP margin of Christiansen (1979) brings his interpretation, as well as that of Klassen (1972), into apparently irresolvable conflict with evidence to the south and east of Saskatchewan. In one of the most closely and certainly dated events in the glacial chronology of central North America, ice advanced southward over a forest bed near Des Moines, Iowa, at 14 000 years BP to deposit the Bemis Moraine (Ruhe 1969). Radiocarbon dates from six samples of wood, including two trees in growth position in loess beneath till, three trees rooted in the top of the loess and pushed over by the advancing ice, and one log incorporated in till, record this advance (Table 1). Lobate patterns and flow indicators confirm that, to reach Iowa, this ice must have flowed through the Lake Agassiz basin (Fig. 1) and over the only southern outlet from this basin, the Minnesota River Valley. In short, it does not seem possible to have water discharging eastward into the Lake Agassiz basin at 14 000 years BP, nor probably at 15 500 years BP, as Christiansen (1979) has shown because the basin was filled with ice, making eastward and southeastward drainage impossible. This point also has been made by Teller (1976) and Teller and Fenton (1980). On the basis of the evidence available in North Dakota, South Dakota, and Iowa, the last major glacial advance across the region reached its maximum western position about 14000 years ago (Clayton et al., in press). We suggest that Christiansen's Phase 2 (16 500 years BP) glacial boundary (Fig. 11) may more closely reflect conditions at 14 000 years BP. While the pattern of deglaciation in southwestern Saskatchewan and Alberta may have occurred as depicted by Christiansen, drainage from these western regions must have been southward into the Missouri River system until sometime after 14 000 years BP, rather than eastward through Lake Agassiz and into the upper Mississippi River system. Although it is not the main purpose of this discussion to explore the reason for Christiansen's unacceptably early chronology of deglaciation, we feel that a comment about the radiocarbon dates he used is pertinent. Nearly all of the dates that are used to document the deglaciation of southern Saskatchewan before 14 000 years BP are from finelydisseminated organic matter in fine-grained sediment (S-522 to S-526, GSC-1369, and S-

Deglaciation

10.1139/e80-051

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Citations (25)

A technique for the rapid determination of the light minerals of detrital sands

Journal of Sedimentary Research (1970)

D. L. Gross Stephen R. Moran

ABSTRACT Determination of light minerals of detrital sands by etching and staining procedures is greatly facilitated with the use of a black roofing tar mounting medium. This medium is unaffected by hydrofluoric acid etching and provides a convenient dark background for counting stained grains with reflected light. The technique is particularly suited for the determination of quartz, chore, and feldspar percentages of large numbers of samples.

10.1306/74d72045-2b21-11d7-8648000102c1865d

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Citations (4)

Smectitic clays and post-reclamation differential subsidence of strip mined areas

Applied Clay Science (1985)

Maurice B. Dusseault J. D. Scott Stephen R. Moran

Overburden

Dewatering

Levelling

10.1016/0169-1317(85)90571-x

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Citations (4)