This dataset is part of the 3D hydrostratigraphic model of the Calgary-Lethbridge Corridor (CLC), southwestern Alberta. It represents the structure top of the Scollard / Willow Creek hydrostratigraphic unit (HSU) in the CLC. Bedrock units included in the CLC model are derived from the Geological Framework of Alberta, a regional geological model of the province. The top of the Scollard / Willow Creek HSU, provided by the Geological Framework of Alberta, was clipped to the CLC model domain for integration into a multi-layer hydrostratigraphic model.
Alberta Geological Survey (AGS) Report 91 includes a full description of the process used to produce this structure grid.
The methodology to create this grid dataset is fully documented in AGS Report 91.
Modelling software used to create grid: Petrel and ArcMap (grid interpolation) and RockWorks16 (deterministic alterations)
The picks detailed below were created and compiled by other authors and reported in this metadata record for user convenience.
Number of data points used: 3196
This includes all Scollard / Willow Creek HSU subsurface stratigraphic picks needed to reproduce the lateral extent of the Scollard / Willow Creek HSU in Alberta, including points that extend outside the CLC model domain.
Data type: Stratigraphic picks from published and unpublished AGS sources and the Alberta Energy Regulator corporate database.
Grid Interpolation Information:
The Geostatistical Analyst ArcMap extension was used to interpolate the elevation value for the top of the Scollard / Willow Creek HSU in Alberta. The following Method Report and Prediction Errors are reproduced in this metadata record for convenience to provide information about the parameters used to create the source grid, as well as the errors associated with the gridding process.
Method Report:
Method: Kriging
Type: Ordinary
Output type: Prediction
Variogram
Number of lags: 12
Lag size: 950
Nugget: 50
Measurement error percentage: 100
Model type: Exponential
Range: 8264
Anisotropy: Yes
Minor range: 5808
Direction: 57.66
Partial sill: 361.96
Prediction Errors
Total points: 3083 (113 of the original inputs point were collocated)
Mean: -0.25
Root mean square error: 21.52
Mean standardized: -0.01
Root mean square error, standardized: 1.23
Average standard error: 16.38
Deterministic Grid Alteration Information:
The grid of the top of the Scollard / Willow Creek HSU in Alberta (500 m cell-size) was exported from Petrel as geographic coordinates (X, Y) as well as elevation data (Z) sampled at each evenly-spaced grid node. The data was then imported into ArcMap and clipped to the CLC model domain. The X,Y,Z data were re-interpolated using closest-point in ArcMap at a 400 m cell-size node spacing, where grid nodes are set equal to the value of the nearest point.
The grid of the top of the Scollard / Willow Creek HSU in the CLC was exported to ESRI ascii format and imported into RockWorks16 for integration into the full hydrostratigraphic model.
Modelling constraints applied:The grid of the top of the Scollard / Willow Creek HSU was constrained to the CLC bedrock topography where the two grids intersected.