Compilation of lithogeochemistry - Abitibi greenstone belt - Ontario portion

The Ontario Geological Survey (OGS) has collected and analysed thousands of rock samples in the Abitibi area over the past 50 years. The field samples were analysed using a wide range of sample preparation and analytical methods. The resulting data were managed and catalogued in an ad hoc manner, often without the metadata that provide the necessary context for interpretation and data integration requirements. Over time, this resulted in confusion and the loss of essential information for effective geochemical data interpretation and archival purposes. This CD presents an Access database that compiles the data from OGS's Lithogeochemistry database (LGC, accessible from http://www.mndm.gov.on.ca/mndm/mines/geologyontario/default_e.asp, which was formerly the PETROCH database of Haus and Pauk, 1993) and 3 more recent MRDs (Miscellaneous Release Data, listed below) in a single database (Abitibi_geochem.mdb). A simpler version of this database, extracted as flat files with location and analytical results (Excel files), is also included. The Access database is presented in ArcGIS format with a detailed geology basemap from Ayer et al, 2004, as well as a regional geology basemap for the periphery of the Abitibi area, modified from Hulbert and Vaillancourt, 2002. Access Database Model In order to better manage the data, a strategy was adopted that focused on the development of a single model for storing geochemical data. The model is based on a conventional relational database model system (RDBMS). The core of the model consists of 10 tables which contain entities that are clearly recognizable by a geochemist (surveys, sites, samples...). The core tables are supported by about 60 peripheral tables. Look-up tables contain unique lists of identifiers for sample type, method of preparation, size fraction, and other characteristic properties for any given survey. The look-up tables define a consistent scientific terminology for describing geochemical surveys. Derived tables contain "flat file" views of the data that are used by other processes, such as internet map servers, which require information for viewing geochemical data in a geographic context as well as simple views of the analytical results for visual browsing by geochemists. The model has been implemented on several relational database management systems, including MS Access, SQL Server and Oracle. It is fully compatible with the metadata standard adopted by the Canadian Geoscience Knowledge Network. To date, the model has been used primarily for storing high-level metadata about geochemical surveys (publicly accessible via http://gdr.nrcan.gc.ca/geochem ). Several initiatives are currently underway, including the Abitibi bedrock geochemistry compilation, to test the model using large amounts of legacy geochemical analytical data. For additional information on the model, contact Steve Adcock at the GSC (adcock@nrcan.gc.ca ).