The dataset includes subsurface stratigraphic picks for the top of the Foremost Formation (Belly River Group) in the Alberta Plains (Townships 1 to 52, Ranges 1W4 to 5W5) made from downhole wireline geophysical well logs. The top of the Foremost was picked at the base of a continuous sandstone or siltstone bed (low-gamma-ray) of variable thickness overlying the Taber coal zone. Well data were screened to detect errors resulting from deviated wells, as well as incorrect ground and kelly bushing elevation data. We used statistical methods to identify local and regional statistical outliers, which were examined individually.

The dataset includes subsurface stratigraphic picks of the top of the Belly River Group in the Alberta Plains (Townships 1 to 50, Ranges 1W4 to 2W5) made from wireline, geophysical well logs. The dataset supplements Alberta Geological Survey Open File Report 2010-10, which describes the methodology. We screened the well data to detect errors resulting from deviated wells, as well as incorrect ground and kelly bushing elevation data. We used statistical methods to identify local and regional statistical outliers, which were examined individually.

This GIS dataset is part of a digital compilation of the bedrock geology of NTS areas 72E, 72L, 73D, and 73E. It is one of the datasets used to produce Alberta Geological Survey (AGS) Maps 567, 568, 569, and 570. This dataset represents the compilation of existing geological maps and original geological mapping by AGS staff. Mapping included field observations and creating three-dimensional models of subsurface stratigraphy based on the interpretation of geophysical logs from oil and gas wells. Each three-dimensional formation surface was projected to a model of the bedrock surface, and the intersection formed the first approximation of the position of the geological contact at the base of the surficial deposits. We adjusted these preliminary contacts to honour outcrop data and the interpretation of the bedrock unit immediately below surficial deposits in individual wells. The data were created in file geodatabase format and output for public distribution in shapefile format. AGS Open File Reports 2010-10 and 2011-13 present additional information on data sources related to this dataset.

The dataset includes subsurface stratigraphic picks for the interfingering members that define the transition between the Belly River Group and the Lea Park Formation in east-central Alberta (Townships 1 to 62, Ranges 1W4 to 21W4) made from wireline geophysical well logs. Coarsening upwards, siltstone to sandstone-dominated members of the Belly River Group include (from youngest to oldest) the upper Birch Lake, lower Birch Lake, Ribstone Creek, Victoria, and Brosseau members. Interfingering mudstone-dominated members of the Lea Park Formation include the Mulga, Grizzly Bear, Vanesti, and Shandro members. Where the top and base are present, we calculated isochore values for each member. Well data were screened to detect errors resulting from deviated wells, as well as incorrect ground and kelly bushing elevation data. We used statistical methods to identify local and regional statistical outliers, which were examined individually.

The Upper Colorado River Basin has a drainage area of about 113,500 square miles in western Colorado, eastern Utah, southwestern Wyoming, northeastern Arizona, and northwestern New Mexico. In the 1980’s and 1990’s, the Upper Colorado River Basin was a study area under of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) program (Sun and Johnston, 1994; Sun and Weeks, 1991). The objectives of the RASA program for the Upper Colorado River Basin were to provide regional assessments of major aquifer systems by providing quantitative assessments of the occurrence, movement, and availability of water stored in rock formations that underlie the basin/watershed. These assessments included: (1) the classification of stratigraphic sequences into those intervals that constitute aquifers and those that constitute confining beds; and (2) the generation of maps that portrayed the areal extent of aquifers, aquifer thickness, and overburden thickness. These studies generated a large body of subsurface geologic information as part of the regional aquifer analyses, some of which are captured in this digital data release. Aquifer systems in consolidated rocks in the Upper Colorado River Basin have been grouped into three major subdivisions of sedimentary rocks; in descending order: (1) Tertiary-rock aquifers, (2) Mesozoic-rock aquifers, and (3) Paleozoic-rock aquifers (Taylor and others, 1983; 1986). Within each aquifer group, rocks are further divided into aquifers and confining units on the basis of lithology, depositional environment, and hydrologic characteristics (Glover and others, 1998; Freethy and Cordy, 1991; Geldon, 2003). In a report describing consolidated-rock aquifers of Paleozoic age, 7 hydrostratigraphic units were defined, four aquifers and three confining units (Geldon, 2003). The hydrostratigraphic units of Paleozoic age are locally exposed around the margins of uplifts and in deeply-incised canyon; they occur widely in the subsurface of the Upper Colorado River Basin study area, except in parts of the Uinta, Wind River, and Uncompahgre uplifts where they have been removed by erosion. These hydrostratigraphic units are part of the stratigraphic sequence of Paleozoic rocks that has a total thickness of more than 5,000 ft. This digital dataset contains spatial datasets corresponding to the contoured subsurface maps of Paleozoic rock units produced by the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) of the Upper Colorado River Basin (Geldon, 2003). The data define the thickness, extent, nomenclature, and facies characteristics of principal hydrostratigraphic units of Paleozoic age in the basin. The digital data describe the following hydrostratigraphic units: the Flathead aquifer, the Gros Ventre confining unit, the Bighorn aquifer, the Elbert-Parting confining unit, the Madison aquifer (consisting of two zones, the Redwall-Leadville zone, and the Darwin-Humbug zone), the Four Corners confining unit (consisting of the Belden-Molas subunit and the Paradox-Eagle Valley subunit), and the Canyonlands aquifer (consisting of three zones, the Cutler-Maroon zone, the Weber-de Chelly zone, and the Park City-State Bridge zone). Contoured thickness and lithology data for each unit are contained in line features classes within a geodatabase; unit extents, facies extents, and formation nomenclatural extents are represented as polygon feature classes. Both types of data are also saved as individual shapefiles. Nonspatial tables define the data sources used, terminology, and the stacking hierarchy and component geologic formations of each the of hydrostratigraphic units

The Upper Colorado River Basin has a drainage area of about 113,500 square miles in western Colorado, eastern Utah, southwestern Wyoming, northeastern Arizona, and northwestern New Mexico. In the 1980’s and 1990’s, the Upper Colorado River Basin was a study area under of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) program (Sun and Johnston, 1994; Sun and Weeks, 1991). The objectives of the RASA program for the Upper Colorado River Basin were to provide regional assessments of major aquifer systems by providing quantitative assessments of the occurrence, movement, and availability of water stored in rock formations that underlie the basin/watershed. These assessments included: (1) the classification of stratigraphic sequences into those intervals that constitute aquifers and those that constitute confining beds; and (2) the generation of maps that portrayed the areal extent of aquifers, aquifer thickness, and overburden thickness. These studies generated a large body of subsurface geologic information as part of the regional aquifer analyses, some of which are captured in this digital data release. Aquifer systems in consolidated rocks in the Upper Colorado River Basin have been grouped into three major subdivisions of sedimentary rocks; in descending order: (1) Tertiary-rock aquifers, (2) Mesozoic-rock aquifers, and (3) Paleozoic-rock aquifers (Taylor and others, 1983; 1986). Within each aquifer group, rocks are further divided into aquifers and confining units on the basis of lithology, depositional environment, and hydrologic characteristics (Glover and others, 1998; Freethy and Cordy, 1991; Geldon, 2003). In a report describing consolidated-rock aquifers of Paleozoic age, 7 hydrostratigraphic units were defined, four aquifers and three confining units (Geldon, 2003). The hydrostratigraphic units of Paleozoic age are locally exposed around the margins of uplifts and in deeply-incised canyon; they occur widely in the subsurface of the Upper Colorado River Basin study area, except in parts of the Uinta, Wind River, and Uncompahgre uplifts where they have been removed by erosion. These hydrostratigraphic units are part of the stratigraphic sequence of Paleozoic rocks that has a total thickness of more than 5,000 ft. This digital dataset contains spatial datasets corresponding to the contoured subsurface maps of Paleozoic rock units produced by the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) of the Upper Colorado River Basin (Geldon, 2003). The data define the thickness, extent, nomenclature, and facies characteristics of principal hydrostratigraphic units of Paleozoic age in the basin. The digital data describe the following hydrostratigraphic units: the Flathead aquifer, the Gros Ventre confining unit, the Bighorn aquifer, the Elbert-Parting confining unit, the Madison aquifer (consisting of two zones, the Redwall-Leadville zone, and the Darwin-Humbug zone), the Four Corners confining unit (consisting of the Belden-Molas subunit and the Paradox-Eagle Valley subunit), and the Canyonlands aquifer (consisting of three zones, the Cutler-Maroon zone, the Weber-de Chelly zone, and the Park City-State Bridge zone). Contoured thickness and lithology data for each unit are contained in line features classes within a geodatabase; unit extents, facies extents, and formation nomenclatural extents are represented as polygon feature classes. Both types of data are also saved as individual shapefiles. Nonspatial tables define the data sources used, terminology, and the stacking hierarchy and component geologic formations of each the of hydrostratigraphic units

The dataset includes subsurface stratigraphic picks of the Milk River 'shoulder' in the Alberta Plains (Townships 1 to 73, Ranges 1W4 to 2W6) made from wireline geophysical well logs. The Milk River 'shoulder' is an informal term often used to refer to a distinctive 'shoulder' (deflection) on resistivity, sonic, density, and porosity logs. The Milk River 'shoulder' corresponds to the top of the Milk River Formation in southernmost Alberta, where it represents juxtaposition between paralic deposits of the underlying Deadhorse Coulee Member of the Milk River Formation and overlying marine shale of the Pakowki Formation. It is characterized by a leftward deflection (decreasing resistivity) upwards across the contact, forming the distinctive 'shoulder signature'. To the north, the Milk River 'shoulder' represents the boundary between the Alderson Member (lower Lea Park Formation) and the upper Lea Park Formation (Pakowki equivalent). In these areas, silty sands and mudstones of the Alderson Member are overlain by shales of the upper Lea Park Formation. Well data were screened to detect errors resulting from deviated wells, as well as incorrect ground and kelly bushing elevation data. We used statistical methods to identify local and regional statistical outliers, which we examined individually.

These structure, isopach and zero edge files are part of a series of stratigraphic framework maps for the Saskatchewan Phanerozoic Fluids and Petroleum Systems (SPFPS) project. The series of stratigraphic framework maps for the Saskatchewan Phanerozoic Fluids and Petroleum Systems (SPFPS) project have been produced using 2 km equi-spaced modified grids generated from Golden Software’s Surfer 9 kriging algorithm. The dataset used to produce each of the maps in this series was created using data from several projects completed by the Ministry (Christopher, 2003; Saskatchewan Industry and Resources et al., 2004; Kreis et al., 2004; Marsh and Heinemann, 2006; Saskatchewan Ministry of Energy and Resources et al., 2007; Heinemann and Marsh, 2009); these data were validated and edited as required to facilitate correlations between the various regional projects. In addition, to minimize edge effects during contouring, the senior author also generated stratigraphic data from wells in adjacent jurisdictions.