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| Title | 3D hydrostatigraphic model of the Southeastern Quebec fractured aquifer system (AFSOQ) | ||||||||||||||||
| Date | 2004-01-01 ( publication)
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| Date | 2004-01-01 ( creation)
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| Presentation form | modelDigital |
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| Type | place |
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| Term | Southwestern Quebec | ||||||||||||||||||||||
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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 | fra; CAN |
| Character encoding | utf8 |
| Thematic category | geoscientificInformation |
| Extent | -74.667000000,45.417000000;-73.667000000,45.917000000 |
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| Format | |
| Name | GOCAD Model |
| 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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| The units that were modeled in the 3D models are: At: Low terrace alluvial sediments, sand, upper aquifer. Ax: High terrace alluvial sediments, sand, upper aquifer. Lb: Lacustrine littoral sediments, sand, upper aquifer. Mb: Marine sublittoral and littoral sediments, sand, upper aquifer. Ma: Fine-grained marine offshore sediments, Champlain Sea silt and clay, aquiclude. Gx: Glaciofluvial ice-contact sediments, aquifer. T: Late Wisconsinian regional undifferentiated till, aquitard. Q: Undifferentiated Pleistocene sediments underlying the regional till, small buried aquifers. R: Undifferentiated bedrock, regional aquifer. |
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| Prior to the construction of the3D model surfaces, one of the most challenging aspects of the modeling task was to adequately correlate borehole attributes to a given stratigraphic unit. Since the known composite stratigraphic sequence is usually incomplete at most sites, correlations must be made carefully. More than 40 cross sections were built to form the basis of the 3D framework. A discrete modeling approach was chosen to construct the geologic model. The 3D geomodeling system Gocad® was used to carry out this part of the work. The surfaces can be built first with non-standardized borehole data to provide quick maps in support of decision-making in the early stages of an investigation and be modified as validation results and new data become available. As more data are added, evaluated and corrected, the surfaces are better constrained and become increasingly accurate. Cross section and geological map contacts are used here as the main expert knowledge constraints, but other constraints were also applied to take into account reliable data between cross sections in order to increase the accuracy of interpolated surfaces. These include topographic data, small outcrops, curves from interpreted seismic profiles, and contacts from boreholes. Since building surfaces separately does not ensure that they are consistently in the correct stratigraphic order away from cross sections, increased mesh density and minimum thickness constraints were applied locally to remove most crossovers. The remaining crossovers were removed manually by adjusting triangle nodes but in many cases, discontinuities were created. Therefore, surfaces are not regionally modified on the basis of a reference layer. The interlocked surfaces are intended to form closed volumes representing geologic bodies. The surfaces thus act as ""dividing walls"" isolating 3D regions (Mallet 2002). In order to achieve this, many improvements were applied along surface intersections. Further discretization was also applied using advanced gridding tools that allow the construction of curvilinear regular 3D grids which conform to the stratigraphic architecture. |
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| File identifier | 59814394-1ae3-3ace-c829-ea4db4064848 |
| 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:26918 |
| 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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