Mapping groundwater storage variations with GRACE: a case study in Alberta,Canada

The applicability of the Gravity Recovery and Climate Experiment (GRACE) to adequately represent broad-scale patterns of groundwater storage (GWS) variations and observed trends in groundwater-monitoring well levels (GWWL) is examined in the Canadian province of Alberta. GWS variations are derived over Alberta for the period 2002–2014 using the Release 05 (RL05) monthly GRACE gravity models and the Global Land Data Assimilation System (GLDAS) land-surface models. Twelve mean monthly GWS variation maps are generated from the 139 monthly GWS variation grids to characterize the annual GWS variation pattern. These maps show that, overall, GWS increases from February to June, and decreases from July to October, and slightly increases from November to December. For 2002–2014, the GWS showed a positive trend which increases from west to east with a mean value of 12 mm/year over the province. The resulting GWS variations are validated using GWWLs in the province. For the purpose of validation, a GRACE total water storage (TWS)-based correlation criterion is introduced to identify groundwater wells which adequately represent the regional GWS variations. GWWLs at 36 wells were found to correlate with both the GRACE TWS and GWS variations. A factor f is defined to up-scale the GWWL variations at the identified wells to the GRACE-scale GWS variations. It is concluded that the GWS variations can be mapped by GRACE and the GLDAS models in some situations, thus demonstrating the conditions where GWS variations can be detected by GRACE in Alberta.     

The variability of heat flow both regional and with depth in southern Alberta, Canada: Effect of groundwater flow?

Detailed studies of terrestrial heat flow in southern and central Alberta estimated on the basis of an order of magnitude larger data base than ever used before (33653 bottom-hole temperature data from 18711 wells) and thermal conductivity values based on detailed rock studies and measured rock conductivities show significant regional and local variations and variations with depth. Heat flow values were estimated for each 3 × 3 township/range area (28.8 × 28.8 km). A difference in heat flow exists between Paleozoic and Mesozoic strata. Generally lower heat flow values are observed in the strata above the Paleozoic erosional surface (20–75 mW m⁻²). Much higher values are estimated for the Younger Paleozoic formations, with large local and regional variations between 40 and 100 mW m⁻².Average heat flow values based on heat flow determinations below and above the Paleozoic surface that agree within 20% show an increase from values less than 40 mW m⁻² in southern and southwestern Alberta to values as high as 70 mW m⁻² in central Alberta. The predominance of regional downward groundwater flows in Mesozoic strata seem to be responsible for the generally observed heat flow increase with depth.The results show that the basin heat flow pattern is influenced by water movement and even careful detailed heat flow measurements will not give correct values of background steady-state heat flow within the sedimentary strata.     

An experimental study of a minette from the Milk River area, southern Alberta, Canada

Buhlmann et al. (Can J Earth Sci 37: 1629–1650, 2000) studied the minettes and xenoliths from the Milk River area of southern Alberta, Canada. Based on previous work, they hypothesized that the minettes were derived from a source containing phlogopite?+?clinopyroxene?±?olivine, at pressures ≥1.7?GPa. To test this hypothesis, liquidus experiments were performed on a primitive minette between 1.33 and 2.21?GPa and between 1,300 and 1,400?°C to constrain the mineralogy of its source region. We found a multiple saturation point along the liquidus at 1.77 GPa and 1,350?°C, where the liquid coexists with orthopyroxene and olivine. Neither phlogopite nor clinopyroxene were found to be liquidus phases, which is inconsistent with Buhlmann et al.’s hypothesis. We suggest that our minette is not primary, but had re-equilibrated with harzburgitic mantle subsequent to formation. In such a scenario, partial melting of a veined source containing mica and clinopyroxene occurred at or near the base of the Wyoming craton (~200?km). Minimal heating or the introduction of hydrous fluids into the source would be required to induce partial melting. Rapid ascent rates, coupled with slow cooling rates, of the “primary minette magma” would preserve the high temperature observed in our experiments. At ~58?km, our “primary minette magma” likely stalled and re-equilibrated with the harzburgite surroundings.     

Measurements and interpretations of36Cl in groundwater,Milk River aquifer,Alberta, Canada

The³⁶Cl/Cl ratios of 12 groundwater samples from the Milk River aquifer were determined by accelerator mass spectrometry. Using known Cl concentrations,³⁶Cl concentrations were deduced. Approximately linear relations were observed between the logarithm of the³⁶Cl concentration, the Cl concentration, and the distance from the recharge area along two flow paths. The results are discussed in two approaches:

• (1)in an interpretation of the linear relation between logarithm of the³⁶Cl concentration and Cl concentration excluding and includingin situ production of³⁶Cl;
• (2)in a diffusion model. The increase of the Cl concentration with the distance from the recharge area is considered to be due to diffusion of Cl from the underlying confining Colorado shale to the aquifer.

Flow velocities ranging between 0.04 and 0.14 m/a, and ages of the groundwater between 0.6 and 2 Ma are obtained at a distance of 80 km from the recharge area.     

Genesis and evolution of the lithospheric mantle beneath the Buffalo Head Terrane, Alberta (Canada)

Mantle xenoliths and xenocrysts were retrieved from three of the 88–86 Ma Buffalo Hills kimberlites (K6, K11, K14) for a reconnaissance study of the subcontinental lithospheric mantle (SCLM) beneath the Buffalo Head Terrane (Alberta, Canada). The xenoliths include spinel lherzolites, one garnet spinel lherzolite, garnet harzburgites, one sheared garnet lherzolite and pyroxenites. Pyroxenitic and wehrlitic garnet xenocrysts are derived primarily from the shallow mantle and lherzolitic garnet xenocrysts from the deep mantle. Harzburgite with Ca-saturated garnets is concentrated in a layer between 135–165 km depth. Garnet xenocrysts define a model conductive paleogeotherm corresponding to a heat flow of 38–39 mW/m². The sheared garnet lherzolite lies on an inflection of this geotherm and may constrain the depth of the lithosphere–asthenosphere boundary (LAB) beneath this region to ca 180 km depth.

A loss of >20% partial melt is recorded by spinel lherzolites and up to 60% by the garnet harzburgites, which may be related to lithosphere formation. The mantle was subsequently modified during at least two metasomatic events. An older metasomatic event is evident in incompatible-element enrichments in homogeneous equilibrated garnet and clinopyroxene. Silicate melt metasomatism predominated in the deep lithosphere and led to enrichments in the HFSE with minor enrichments in LREE. Metasomatism by small-volume volatile-rich melts, such as carbonatite, appears to have been more important in the shallow lithosphere and led to enrichments in LREE with minor enrichments in HFSE. An intermediate metasomatic style, possibly a signature of volatile-rich silicate melts, is also recognised. These metasomatic styles may be related through modification of a single melt during progressive interaction with the mantle. This metasomatism is suggested to have occurred during Paleoproterozoic rifting of the Buffalo Head Terrane from the neighbouring Rae Province and may be responsible for the evolution of some samples toward unradiogenic Nd and Hf isotopic compositions.

Disturbed Re–Os isotope systematics, evident in implausible model ages, were obtained in situ for sulfides in several spinel lherzolites and suggest that many sulfides are secondary (metasomatic) or mixtures of primary and secondary sulfides. Sulfide in one peridotite has unradiogenic ¹⁸⁷Os/¹⁸⁸Os and gives a model age of 1.89±0.38 Ga. This age coincides with the inferred emplacement of mafic sheets in the crust and suggests that the melts parental to the intrusions interacted with the lithospheric mantle.

A younger metasomatic event is indicated by the occurrence of sulfide-rich melt patches, unequilibrated mineral compositions and overgrowths on spinel that are Ti-, Cr- and Fe-rich but Zn-poor. Subsequent cooling is recorded by fine exsolution lamellae in the pyroxenes and by arrested mineral reactions.

If the lithosphere beneath the Buffalo Head Terrane was formed in the Archaean, any unambiguous signatures of this ancient origin may have been obliterated during these multiple events.     

Zeolite and clay-carbonate assemblages in the Blairmore Group (Cretaceous) southern Alberta Foothills,Canada

Zeolites, calcite, quartz, kaolinite, chlorite and other authigenic minerals occur in the non-marine sandstones of the Lower Cretaceous Blairmore Group of the southern Alberta Foothills, Canada. Zeolites are restricted to plagioclase-rich sandstones and do not occur with kaolinite. Laumontite and barian-strontian heulandite (containing up to 6.9 weight percent BaO and 4.1 weight percent SrO) generally occur as pore fillings, but laumontite also occurs within albitized plagioclase. About 80 percent of plagioclase grains examined by electron microprobe are partly to completely albitized. A structural-stratigraphic reconstruction of the areas sampled indicate maximum burial depths, including tectonic thickening, in the range 4.7 to 7.8 Km, with P load ～1 to ～2 Kb, respectively. A comparison of mineral assemblages in Blairmore rocks with published experimental data suggest T did not exceed ～250°–280°C, depending on the load pressure. If P _H2O∶P load, the presence of laumontite and albite suggest minimum T on the order of 150°–180°C. The lack of lawsonite suggests P-load <3Kb, which is compatible with structural-stratigraphic data. The occurrence of the alternative assemblages calcite-kaolinite-quartz and laumontite implies gradients in f _CO2/f _HO2. Assemblages containing laumontite presumably equilibrated with fluids having X _CO2a Mg⁺⁺/a (H⁺)². X-ray diffraction studies on disordered graphitic material indicate a comparable degree of graphitization between Blairmore graphitic material and that found in zeolite facies assemblages elsewhere. If log f _O2 were at least as low as that defined by quartz-magnetite-fayalite buffer, disordered graphite could not have equilibrated with fluids of the same composition as those equilibrated with laumontite or kaolinite.     

Origin and significance of mud-filled incised valleys (Upper Cretaceous) in southern Alberta, Canada

Seven mud-filled incised valleys (MFIVs) in the paralic facies of the Dinosaur Park and Horseshoe Canyon formations (Upper Cretaceous) of southern Alberta were studied to better understand their morphology, geometry and depositional histories in an estuarine context. Two preservational geometries occur: simple, U-shaped forms; and internally complex forms. Both types of MFIV record deposition in the central zone of low energy (turbidity) in an estuarine setting. Simple, U-shaped MFIVs have sharp basal erosional surfaces and consist of mudstone-dominated heterolithic fills of channel-wide, concave-up laminae. Associated fossil assemblages are marine to brackish. Each simple MFIV records a cut-and-fill history associated with a cycle of relative sea-level drop and rise. Low-energy depositional settings, loss of channel form during infilling, and associated shoreface deposits, as well as the absence of clear tidal indicators suggest a coastal plain estuarine setting, along a wave-dominated, barred coastline. Complex MFIVs are rarer, and consist of imbricated, wedge-shaped sets of inclined-to-horizontal heterolithic strata. Tidal deposits and/or nonmarine-to-marine macrofossils occur locally. Complex MFIVs were infilled in meandering reaches of the central zone of low energy in tide-dominated estuaries. Their rarity compared to simple MFIVs and their freshwater palaeontological content suggest that they were contiguous landward with extensive fluvial channels. A complex MFIV near Onefour comprises three in-channel depositional cycles. Each cycle consists of an erosional surface overlain by lateral accretion bedding and a conformable transition to vertically aggraded strata. Each cycle reflects a cut-and-fill event under the control of changes in relative sea-level that culminated in overbank flooding. All MFIVs formed in low-gradient settings (≤0.03%) where estuarine zones were stretched out over many tens of kilometres. Tide-dominated estuaries apparently exhibited simple, straight-to-meandering upstream transitions and extensive landward penetration (≥200 km) of tidal backwater effects. Few modern estuaries serve as adequate modern analogues to these ancient, tide-dominated estuaries. Radiometric data indicate that MFIV cut-and-fill cycles were 100 000-400 000 years in maximum duration and thus, equivalent to 4th order sea-level cycles. However, negative evidence tentatively suggests that these cycles took place over time intervals 1-2 orders of magnitude smaller (5th order or higher sea-level cycles).     

Genesis of the Woodstock drumlin field, southern Ontario, Canada

The Woodstock drumlin field was formed about 15,000 years ago during the Port Bruce Stadial of the Late Wisconsinan. It consists of three sections, each composed of texturally different till sheets (Tavistock A, B and C Tills) deposited during marginal oscillations of the Huron ice lobe advancing from the Lake Huron depression. A statistically significant relation between till texture and drumlin morphometry has been determined. Features composed of clayey-silt Tavistock A Till are smaller and more elongate than those built up of sandy-silt Tavistock C Till, which reflects a different susceptibility of the drumlin deposits to the moulding action of the glacier. Based on the field data it is suggested that the drumlinizing glacier was temperate all the way up to its margin and basal sliding occurred also at its outermost peripheries. In the drumlin region immediately behind end moraines the shear strength/shear stress ratio was around I and increased progressively in the upstream direction. In the proposed mechanism of drumlin formation the key factor is pore water dissipation (1) through the permeable substratum and (2) into dilatantly expanding granular deposits, both resulting in the necessary increase of the basal till strength.     

Watershed-scale response of groundwater recharge to inter-annual and inter-decadal variability in precipitation (Alberta,Canada)

Groundwater recharge sets a constraint on aquifer water balance in the context of water management. Historical data on groundwater and other relevant hydrological processes can be used to understand the effects of climatic variability on recharge, but such data sets are rare. The climate of the Canadian prairies is characterized by large inter-annual and inter-decadal variability in precipitation, which provides opportunities to examine the response of groundwater recharge to changes in meteorological conditions. A decadal study was conducted in a small (250 km²) prairie watershed in Alberta, Canada. Relative magnitude of annual recharge, indicated by water-level rise, was significantly correlated with a combination of growing-season precipitation and snowmelt runoff, which drives depression-focussed infiltration of meltwater. Annual precipitation was greater than vapour flux at an experimental site in some years and smaller in other years. On average precipitation minus vapour flux was 10 mm y^?1, which was comparable to the magnitude of watershed-scale groundwater recharge estimated from creek baseflow. Average baseflow showed a distinct shift from a low value (4 mm y^?1) in 1982–1995 to a high value (15 mm y^?1) in 2003–2013, indicating the sensitivity of groundwater recharge to a decadal-scale variability of meteorological conditions.     

Fluorine in formation waters,Alberta Basin,Canada

Fluorine is a common minor constituent of formation waters throughout the Alberta Basin, and it was detected in each of the 469 samples analyzed for it. Contents range up to 22 mg/l, with an arithmetic mean of 1.83 mg/l and a median value of 1.20 mg/I. There is a trend toward increased mean and median contents of F from the shallower, cooler, less saline formation waters to the deeper, hotter, more saline formation waters. This trend parallels a trend of increasing saturation with respect to fluorite, with most of the less saline formation waters being undersaturated with respect to fluorite. At the same time, the major portion of F occurs as F⁻ in the less saline formation waters, with increasing amounts held as MgF⁺ as the Ca content, ionic strength and temperature increase. Complexes between Al and F, and VO and F account for only a relatively minor portion of the complexed F. A significant portion of the F in high-salinity formation waters from marine strata could well have originated from the initial seawater. However, it is speculated that water-rock reactions with bentonite or bentonitic shales may have to be invoked to account for the very high contents of F in the less saline formation waters from some of the shallow, cooler, non-marine aquifers of the Upper Cretaceous post-Colorado aquifer-aquitard system. Finally, it is possible to use knowledge of the distribution of F in formation waters from individual aquifers to check on the “correctness” of F determinations (primarily when formation waters of similar composition show saturation with respect to fluorite), and in the same case to predict the F content of formation waters in the Alberta Basin for which only the appropriate major ions have been determined.     

Subglacial Lake McGregor, south-central Alberta, Canada

It is proposed that a lake, here named “Subglacial Lake McGregor”, existed beneath the Laurentide Ice Sheet at, or near, the last glacial maximum. The lake resided in the ancient buried McGregor and Tee Pee preglacial valleys, which are now mostly filled with glacigenic deposits. The greatest thickness of sediment in the valleys is in the form of chaotically deposited lake beds that were laid down in a subaqueous environment by a number of process: gravity flow, water transport, and suspension settling. Topographic, sedimentary, and stratigraphic evidence point to a subglacial, not a proglacial, origin for the beds. During the early stages of lake existence, ice movement was significant as there are numerous sets of shear planes in the sedimentary beds. This indicates that the lake filled (lake sedimentation) and drained (shearing of the beds by overlying ice when ice contacted the bed) often. Thus, early in its history, the lake(s) was/were ephemeral. During the later stages of lake existence, the lake was relatively stable with no rapid draining or influx of sediment. Gradual drainage of the lake resulted in lowering of the ice onto the lake beds resulting in subglacial till deposition. Drainage was not a single continuous event. Rather it was characterized by multiple phases of near total drainage (till deposition), followed by water accumulation (lake sedimentation). Water accumulation events became successively less significant reflected by thinning of lake beds and thickening of till beds higher in the stratigraphic sequence. Since subglacial lake sedimentation appears to be restricted to the subglacial valleys, it is suggested that the valleys acted as a large-scale interconnected cavity system that both stored and transported water. It is also suggested that these acted as the main routes of water flow beneath the Laurentide Ice Sheet.     

Application of the stable isotope composition of S04 to tracing anomalous TDS in Nose Creek,southern Alberta,Canada

Nose Creek, a tributary of the Bow River, has a TDS load that is significantly higher than the Bow River or its other tributaries. Chemical and stable isotope analyses were used to elucidate the sources of TDS in Nose Creek. Oxygen and H isotopes indicate that water is added to Nose Creek by leaky municipal pipes, via groundwater infiltration, as the creek flows through the cities of Airdrie and Calgary. Upstream of Airdrie, the high δ³⁴S of dissolved S0₄ (+ 17‰), is consistent with derivation from the local sour gas industry. The S0₄ concentration of Nose Creek doubles as the creek flows through agricultural land between Airdrie and Calgary, while the δ³⁴S composition remains a consistent 5‰. This is indicative of S derived from local soils. Within Calgary, S0₄ is derived from oxidation of reduced forms of S in the till, related to the influx of municipal groundwater.     

Mammoth tracks indicate a declining Late Pleistocene population in southwestern Alberta,Canada

Much debate has raged over the role that early humans played in this most recent large extinction. Fossil mammoth (Mammuthus primigenius) footprints were discovered at the St. Mary Reservoir in southwestern Canada (Wally's Beach DhPg-8). They are located in aeolian sediment dated at 11,300–11,000 years BP. By comparing the size distribution of these tracks with those of modern African elephants (Loxodonta africana), the age distribution of this mammoth population was determined. Containing far fewer juveniles than would be expected for an expanding or stable population, these tracks provide the first evidence that a living mammoth population, coexisting with human inhabitants, was in decline. Additionally, the same site provides corroborating evidence of humans hunting megafauna (horse and bovids). This suggests that humans, in addition to climate change, played a role in the end Pleistocene extinctions in North America.     

Localized zones of denitrification in a floodplain aquifer in southern Wisconsin, USA

A floodplain aquifer within an agricultural watershed near Madison, Wisconsin (USA), was studied to determine whether denitrification was occurring below the surface organic layer. Groundwater levels and concentrations of O₂, Cl^?, NO ₃ ^? , SO ₄ ^2? , dissolved organic carbon (DOC), and major cations were monitored over a 1-year period along a 230-m transect between an agricultural field and a stream discharge point. Seventeen groundwater samples were analyzed for δ¹⁵N_NO3 and δ¹⁸O_NO3 composition. Samples in which NO ₃ ^? was too low for stable isotope analysis were analyzed for excess dissolved N₂. Groundwater NO ₃ ^? concentrations declined between the agricultural field and the discharge point. Chloride and δ¹⁵N_NO3/δ¹⁸O_NO3 data indicated that the drop in NO ₃ ^? was caused primarily by dilution of shallow NO ₃ ^? -rich water with deeper, NO ₃ ^? -depleted groundwater. Two localized zones of denitrification were identified in the upland-wetland transition by their δ¹⁵N_NO3 and δ¹⁸O_NO3 signatures, and two in the stream hyporheic zone by the presence of excess dissolved N₂. The combined stratigraphic, hydrologic, and geochemical data in these locations correspond to groundwater mixing zones where NO ₃ ^? is delivered to subsurface layers that support denitrification fueled by dissolved (e.g. DOC or dissolved Fe(II)) and/or solid-phase (e.g. particulate organic carbon, solid-associated Fe(II), or pyrite) electron donors.     

Interpretation of fracture and physiographic patterns in Alberta,Canada

Thousands of linear elements (joint traces, river trends and photolinears) have been identified and statistically analysed in the Province of Alberta, Canada, from the U.S. border to the Fort McMurray area. A statistical evaluation was performed on the data by fitting Dimroth-Watson distributions to groups of them. It is suggested that the joints represent shear surfaces formed in a neotectonic stress field whose maximum compression is oriented normal to the front of the Rocky Mountains, at least in the vicinity of that range. Further to the northeast, the stress trajectories swing to E-W and N-S directions. The river courses in Alberta do not align themselves with the joints and are presumably controlled by the general slope of the land towards Hudson's Bay. The photolineaments are features of uncertain origin and age.     

Der Tektonische Stil der Rocky Mountains in Alberta,Canada

Zusammenfassung Die Canadian Rockies bestehen aus westfallenden, relativ über das Prärie-Becken nach E transportierten Abscher-Decken, deren Gefüge an 3 Beispielen aus Süd-Alberta beschrieben wird. In der Tiefe herrscht Transport, Plättung und a-Längung, nahe der ursprünglichen Oberfläche Einengung und b-Längung. Da das transportierte Material die Grenze zwischen beiden Gefüge-Typen überschreitet, entsteht in der oberen Zone ein Überlagerungs-Gefüge, dessen Erklärung als zweiphasige Verformung bestritten und das als ortskonstanter stoffvariabler Formungsraum (Sander) bezeichnet wird.     

Sediment production and transport in a proglacial stream: Hilda Glacier, Alberta, Canada

Hilda Glacier, a small cirque glacier in the Canadian Rocky Mountains, yields two principal types of sediment: ablation till, deficient in fine material and produced by rockfalls and avalanches falling on to the glacier surface, and basal lodgement till, rich in fines and formed mainly by subglacial erosion. Recent recession from its Neoglacial maximum has exposed large areas of basal till with thin veneers of ablation till which, when combined with present subglacial and supraglacial debris, provide abundant material for erosion and transport by the mcltwatcr stream. Sediment transport measurements over two summers (1977–1978) showed that bed load and suspended load occur in approximately equal proportions and that dissolved loads are minor. Local source variations, especially bank slumps, are a major cause of scatter in sediment rating curves. Suspended-sediment concentrations are greater early in the melt season due to availability of loose sediment produced by freezing and thawing. Other contributors to scatter in suspended-sediment rating curves include rain showers and diurnal hysteretic effects. Although the distinction between bed load and suspended load is never sharp, available data suggest that the sand/ gravel grain-size boundary (-1ø) approximates the suspendcd-load/bed-load division for characteristic Hilda flows transporting gravel. This approximation, combined with till grain-size analyses, suspended-sediment measurements, and spatial distributions of till types, leads to the following computations of fluvial sediment sources: for suspended load - 6% supraglacial, 47% subglacial, 47% channel banks; for bed load - 46% supraglacial, 27% each subglacial and channel banks. Supraglacial debris provides only about one-fourth of all fluvial sediment, but nearly half of the bed load.     

A tidal-inlet complex in the Cretaceous epeiric sea of North America: Virgelle Member, Milk River Formation, southern Alberta, Canada

The upper portion of the Virgelle Member (Upper Cretaceous Milk River Formation) at Writing-on-Stone Provincial Park of southern Alberta preserves evidence of tidal processes along an otherwise wave-dominated, progradational shoreline in the Cretaceous Interior Seaway of North America. The upper Virgelle Member is underlain by offshore transition to lower shoreface deposits of the Telegraph Creek Member and the lower Virgelle Member, respectively, and is overlain by the non-marine shales and sandstones of the Deadhorse Coulee Member. The sediments of the upper Virgelle Member were deposited along a prograding shoreline and are interpreted here as those of a tidal-inlet complex. Most inlet sections consist of an erosional base overlain by a shale-pebble conglomerate, followed by cross-bedded sandstones which become finer-grained and decrease in scale upwards. Indicators of tidal processes include palaeocurrent distributions, mud couplets, tidal bundles, re-activation surfaces and herringbone cross-beds. The sequence through the tidal-inlet complex can be differentiated, according to prevalent palaeoflow directions and sedimentary structures, as ebb-dominated, flood-dominated, or mixed-tidal influence. Ebb-dominated sections commonly contain lateral accretion surfaces whereas flood-dominated sections contain tidal-ramp deposits. Back-barrier lagoon deposits are dominated by sandstones of an extensive flood-tidal delta with only thin shales preserved locally at the top of the inlet complex. Deposits of ebb-tidal deltas are absent, presumably due to the effective sediment dispersal by waves and wave-induced longshore currents acting on the regionally wave-dominated shoreline.     

西加拿大盆地油砂储层中的泥夹层特征

西加拿大盆地含有丰富的油砂资源,主要产于阿尔伯达省东北部的下白垩统马克马里组(McMurray Formation)．该组含有不等的砂泥斜互层．这些砂泥斜互层(IHS)在局部很发育．描述其中的泥夹层为建立客观的储层模型提供了的重要数据．试图从6个方面对泥夹层进行描述并简要讨论如何利用这些描述结果去建立客观有效的储层模型．