Geochronology is a discipline of geoscience which measures the age of earth materials and provides the temporal framework in which other geoscience data can be interpreted in the context of Earth history. This knowledge helps to answer questions such as when did a volcano last erupt, what is the rate of crustal uplift in a specific area, are rocks at one gold prospect the same age as those at another.Distributed from [GeoYukon](https://yukon.ca/geoyukon) by the [Government of Yukon](https://yukon.ca/maps) . Discover more digital map data and interactive maps from Yukon's digital map data collection.For more information: [geomatics.help@yukon.ca](mailto:geomatics.help@yukon.ca)

A hydrogeological unit is defined as any soil or rock unit or zone that by virtue of its hydraulic properties has a distinct influence on the storage or movement of groundwater. It is considered the main dataset from the GGP point of view. Hydrogeological units are ranked into five levels (from largest to smallest): 1) hydrogeological region, 2) hydrogeological context, 3) aquifer system, 4) hydrostratigraphic unit, and 5) aquifer. Here are formal definitions for these different types of hydrogeologic units. - Hydrogeological region Hydrogeological regions are areas in which the properties of sub-surface water, or groundwater, are broadly similar in geology, climate and topography. There are 9 such regions identified in Canada (ref?). - Hydrogeological context Hydrogeological contexts are units of reporting, conceptually narrower than regions, and are additionally delineated by physiographic and hydrogeological aspects. - Aquifer system ""A heterogeneous body of intercalated permeable and poorly permeable material that functions regionally as a water-yielding hydraulic unit; it comprises two or more permeable beds [aquifers] separated at least locally by aquitards [confining units] that impede groundwater movement but do not greatly affect the regional hydraulic continuity of the system"" (Poland et al., 1972). - Hydrostratigraphic unit (HSU) ""Body of sediment and/or rock characterized by ground water flow that can be demonstrated to be distinct under both unstressed (natural) and stressed (pumping) conditions, and is distinguishable from flow in other HSUs"" (Noyes et al.) - Aquifer ""A formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs"" (Lohman et al, 1972, p. 21). The rank attribute is used to specify the scope of the described unit. The general principle behind this specification is to allow the same data structure to apply to various types of hydrogeological units, from the local aquifer to the almost continental hydrogeological region. The dataset includes properties such as identification, physiography, geology, aquifer description and properties, water balance, groundwater use and risk. It features numerical values or a general description when no values are available. The description can also be used to add context to the numerical values. For each property, metadata identifying the source of the original data, links to similar data in GIN, and description of the processes, algorithms or methodology used to obtain these datasets will be available to complement the data. This dataset is designed to capture and represent a set of synthesized information pertaining to hydrogeological units through maps and succinct table reports. Some attributes (or properties) of the dataset are irrelevant depending of the rank of the unit. In general, this dataset is organised to include multiple properties associated with aquifers and larger hydrogeologic units. These properties are grouped into categories, which include identification, physiography, geology, aquifer description, water balance, groundwater use and risk. The numerical values associated with each of the properties can be used to create thematic maps; hence, the importance of using standardized units of measurement and definitions for these properties. When numerical values are not available, a general description may be supplied instead. The description can also be used to add context to the numerical values. Because this dataset is the cornerstone of the national view on groundwater, supplemental contextual information (metadata) must be part of the data. Thus, for each property, metadata identifying the source of the original data, links to similar data in GIN, and a description of the processes, algorithms or methodology used to obtain these datasets will be available to complement the data.

Geochronology is a discipline of geoscience which measures the age of earth materials and provides the temporal framework in which other geoscience data can be interpreted in the context of Earth history. This knowledge helps to answer questions such as when did a volcano last erupt, what is the rate of crustal uplift in a specific area, are rocks at one gold prospect the same age as those at another.

British Columbia Digital Geology is the data source used for the seamless province-wide, up-to-date, and detailed bedrock geology. The bedrock geology is standardized with consistent stratigraphic code and geometries, and integrates all details of compilations from 1:50,000 to 1:250,000. The latest release (Open File 2017-8) is maintained by a geospatial frame data model, which consists of attributed geological contacts and faults as linework, and outcrops or centroids as points attributed with bedrock information. Techniques are used to simplify the integration process and shorten the timeframe from field mapping, compilation, integration, to data delivery. The release also contains: tables for geological units and colours; ESRI layer files containing bedrock colour symbols; and a map of British Columbia illustrating the suggested colour theme for the bedrock polygons. Related data sets are Geology Faults and Quaternary Alluvium and Cover. Bedrock Geology is interactive with other geoscience data on MapPlace and MapPlace 2 and is available for download in shapefile format.

This dataset was developed for inclusion in EXTECH IV Athabasca uranium multidisciplinary study project geoscience database.This dataset was developed for inclusion in the EXTECH IV Athabasca uranium multidisciplinary study project geoscience database. It includes the Athabasca Basin paleocurrent directions and was compiled from paper field data sheets. **Please Note – All published Saskatchewan Geological Survey datasets, including those available through the Saskatchewan Mining and Petroleum GeoAtlas, are sourced from the Enterprise GIS Data Warehouse.  They are therefore identical and share the same refresh schedule. 

Location of rock samples collected during Precambrian mapping projects more recent than 1985 in northern Saskatchewan and stored at the Subsurface Laboratory.Location of rock samples collected during Precambrian mapping projects more recent than 1985 in northern Saskatchewan and stored at the Subsurface Laboratory. This is an on-going compilation so not all map projects are present. The data was created as a file geodatabase feature class and output for public distribution. **Please Note – All published Saskatchewan Geological Survey datasets, including those available through the Saskatchewan Mining and Petroleum GeoAtlas, are sourced from the Enterprise GIS Data Warehouse.  They are therefore identical and share the same refresh schedule. 

To support improved groundwater geoscience knowledge for southern Ontario, a regional 3-D model of the surficial geology of southern Ontario has been developed as a part of a collaboration between the Ontario Geological Survey and the Geological Survey of Canada. Covering approximately 66,870 km2 in area, the model is a synthesis of existing geological models, surficial geology mapping, and subsurface data. The model is a simplified 9-layer reclassification of numerous mapped local surficial sediment formations in places over 200 m thick with a total volume of approximately 2,455 km3. The model integrates 1:50,000 scale surficial geology mapping with 90 m bathymetrically corrected topographic digital elevation model (DEM) and 8 existing local 3-D models. Archival subsurface data include 10,237 geotechnical and stratigraphic boreholes, 3,312 picks from geophysical surveys, 15,902 field mapping sites and sections, 537 monitoring and water supply wells and 282,995 water well records. Roughly corresponding to regional aquifer and aquitard layers, primary model layers are (from oldest to youngest): Bedrock, Basal Aquifer, Lower Sediment, Regional Till, Post Regional Till Channel Fill, Glaciofluvial Sediment, Post Regional Till Mud, Glaciolacustrine Sand and Recent Sediment / Organics. Modelling was completed using an implicit modelling application (LeapFrog®) complemented by an expert knowledge approach to data classification and rules-based Expert System procedure for data interpretation and validation. An iterative cycle of automated data coding, intermediate model construction and manual data corrections, expert evaluations, and revisions lead to the final 3-D model. A semi-quantitative confidence assessment has been made for each model layer surface based on data quality, distribution and density. This surficial geology model completes the development of a series of regional 3-D geological and hydrogeological models for southern Ontario.

Hydraulic properties characterize a hydrogeological unit. The hydraulic properties considered for this dataset are the transmissivity, the hydraulic conductivity, the storage coefficient, the specific storage coefficient and the porosity. Hydraulic properties are estimated by performing aquifer tests (pumping tests, slug tests). The hydraulic tests and their duration are managed in this dataset. The methods used to create the dataset are described in the metadata associated with the dataset. The dataset exhibits a general description of hydraulic properties of the hydrogeological unit, including hydraulic test, total test duration, method and date. It includes numbers and/or ranges describing the aquifer tests results. Note that an alternate raster representation could be used in complement to the discrete point-based representation.

Level below which soil or rock is saturated with water, in the well and at the time the level has been measured, expressed in m above the sea level. Groundwater levels measured are interpolated / extrapolated to obtain groundwater level on every cell of the hydrogeological unit raster. Surfer and ArcGis are the software usually used to create groundwater level raster. The dataset designates a raster with a groundwater level, for each cell of the hydrogeological unit.

A measure of the intrinsic susceptibility of an aquifer representing the tendency or likelihood for contaminants to reach a specified position in the groundwater system after introduction at some location above the uppermost aquifer. The method used to create the dataset is described in the metadata associated with the dataset. The dataset is a general assessment of the vulnerability of the hydrogeological unit considered as a whole. It features the local and regional qualifiers in a controlled vocabulary list referring to the extent where the vulnerability value is valid. Because the vulnerability is assessed using contextual indices linked to the regional hydrogeological settings, it is very unlikely to have an homogeneous range of data throughout the various hydrogeologic units across the country for this dataset. Hence, the vulnerability dataset will not qualify as an homogeneous dataset. A more generic reclassification using for examples three vulnerability classes could then be used to solve this problem. Each sub layers used to create the global vulnerability index can be provided along with the final vulnerability index map.