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| Title | 3D hydrostatigraphic model of the Spiritwood Buried Valley | ||||||||||||||||
| Date | 2015-01-01 ( publication)
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| Date | 2015-01-01 ( creation)
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| Presentation form | modelDigital |
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| Series | Open File7866 | ||||||||||||||||
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| Type | place |
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| Term | Spiritwood Buried Valley | ||||||||||||||||||||||
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| Type | theme |
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| Term | Quaternary | ||||||||||||||||||||||
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| Type | product |
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| Term | 3D Model | ||||||||||||||||||||||
| Spatial representation | vector |
| Language | eng; CAN |
| Character encoding | utf8 |
| Thematic category | geoscientificInformation |
| Extent | -100.101721000,48.805759000;-98.955107000,49.501807000 |
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| Format | |
| Name | DXF |
| Version | not applicable |
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dataset
Date lineage
Lineage is the description of the sources and steps used to create the current dataset.
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| Leapfrog® Hydro is designed to simplify the model-building process by providing a clear workflow from 3D model extents setup, data input, stratigraphy building, editing and rendering to conversion and export to hydrogeological flow modelling formats (e.g. FEFLOW, MODFLOW). The topographic DEM was imported and set as the model topography. Stratigraphic code contacts found in the boreholes dataset are scanned, tabulated and used by the software to semi-automatically build stratigraphic layers of the model. The bedrock channel points developed from HRSR profiles were used to augment the bedrock surface. A 3D volume model is created in Leapfrog® Hydro by developing a series of stratigraphic layers based on contacts within boreholes, layer surface points, lines and/or raster grids (Alcaraz et al., 2011). The type of layer selected determines how Leapfrog® Hydro solves ambiguous data geometries to produce an appropriate volume conforming to the geological features present. Leapfrog® Hydro first interpolates each stratigraphic layer surface independently using Radial Basis Functions (RBF) then rationalizes overlaps based on age relationships and type of layer. Because the numerous inter-till aquifer deposits are generally enclosed within the upper regional aquitard, the intrusive layer type was used to simplify the model-building process. With a preliminary model developed from borehole stratigraphic contacts and HRSR bedrock surface points, additional control on layer geometries was introduced through iterative polyline editing. Several iterations of model inspection and stratigraphic code assignment checking were undertaken throughout the modelling process. Coding revisions and/or surface edits were made for each iteration until model geometries and unit interrelationships conformed adequately to expert knowledge. Leapfrog® Hydro's workflow process automatically re-interpolates surfaces and rebuilds the model as a result of adding new data, editing existing borehole data or editing the model itself. This greatly simplified making iterative revisions to the model. |
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| A model stratigraphy has been adopted that tries to capture the key hydrostratigraphic elements of the conceptual geologic model and deals with the limitations of the stratigraphic information content within the water well records and the pragmatic requirements of geological modelling software. Because the water well records cannot distinguish between different tills nor capture all the numerous unconformities caused by erosion of bedrock valleys and channels within the till, the model stratigraphy does not attempt to honor a detailed geological stratigraphy or chronostratigraphy. Rather, it tries to represent the continuity of hydrostratigraphic units, even if these include different geological units. From deepest to surface, the following 13 hydrostratigraphic units are modelled: 1) Shale bedrock (100): Below the jointed and fractured surface of the Pierre Formation, all members are grouped together as a lower permeability shale unit. 2) Fractured shale bedrock (100_A): The upper surface of the shale is usually jointed and more highly fractured as a result of weathering and unloading and therefore may be more permeable than the underlying intact shale. 3) Sandstone bedrock (101): Although the Boissevain Formation sandstone is likely the more permeable of the two, both the Turtle Mountain and Boissevain Formations are likely more permeable than the Pierre Formation and so are combined here and modelled as a single low yield aquifer (Betcher et al., 1995). The Boissevain Formation is equivalent to the Fox Hills Formation in North Dakota whereas the two members of the Turtle Mountain Formation are equivalent to the Hell Creek Formation and Fort Union Group (Bamburak, 1978; Randich and Kuzniar, 1984a; Grasby et al., 2014). 4) β valley aquitard (200): This low permeability unit, consisting of glacial till or glaciolacustrine clay, occurs at the base of the β valley primarily in North Dakota where it has been observed in borehole logs. 5) β valley aquifer (300): Based on the HTEM and HRSR results and the borehole logs, permeable sand and gravel appears to partially fill the eastern β valley whereas it may fill the western β valley and even have extended into the broader α valley in some areas. 6) Lower regional aquitard (401): Discontinuous basal till occurs both within and outside the α valley. Outside the β valley, it is on bedrock. Although till within or overlying the β valleys may be younger and belong to a different till unit, the lower regional aquitard is nonetheless modelled as a single, continuous unit across the β valleys where till is present in the borehole logs. 7) Lower regional aquifer (501): This permeable sand and gravel unit is based predominantly on depth rather than origin. It is typically encountered at depths greater than 30 m. Similar to the lower regional aquitard, the lower regional aquifer is also modelled as a single, continuous unit across the β valleys. 8) Upper regional aquitard (402): Although more than two regional tills may be present, this unit represents the main till aquitard that extends from the deep regional sand and gravel to near ground surface. 9) Inter-till aquifer (502): This unit represents the majority of permeable sediment above the deep regional sand and gravel unit. These are typically inter-till sands and gravels that are associated with γ valley channel or fan deposits. Many boreholes record more than one inter-till sand and gravel interval. This unit generally lies within the upper regional aquitard but extends up to surface in some areas and down to shallow bedrock in others. 10) Fractured upper regional till (402_A): Where the till of the upper regional aquitard extends to surface, it is usually oxidized and fractured. The enhanced permeability of this unit may be important for groundwater recharge and the development of localized shallow groundwater flow systems. 11) Upper glaciofluvial (700): A thin, permeable glaciofluvial sand and gravel unit either near or at the ground surface. This unit appears on surficial geological maps. 12) Upper glaciolacustrine (800): A thin, lower permeability glaciocustrine silt and clay unit either near or at the ground surface. This unit appears on surficial geological maps. 13) Recent (900): Various recent units including organic deposits in wetlands, alluvial sediments and colluvium predominantly in the Pembina Valley. |
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| File identifier | 81740652-e09a-803d-7f67-d4d0be686b28 |
| Language | eng; CAN |
| Character encoding | utf8 |
| Hierarchical classification | dataset |
| Date | 2017-03-24 |
| Metadata standard | North American Profile of ISO 19115:2003 - Geographic information - Metadata |
| Version | CAN/CGSB-171.100-2009 |
| Constraints | |
| Update frequency | asNeeded |
| Reference System code | EPSG:26914 |
| Register | http://www.epsg-registry.org/ |
| Version | 6.14 |
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| Name | Francois Letourneau | ||||||
| Organisation | Government of Canada; Natural Resources Canada; Geological Survey of Canada - GSC Quebec | ||||||
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| Organisation | Government of Canada; Natural Resources Canada; Geological Survey of Canada | ||||||
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