Glacial secrets: clay at the surface gives clues about what's deep underground in central BC
Vancouver, BC - February 23, 2018 -Data from two new Geoscience BC-funded projects provides new insights on how sediment left by glaciers at the surface in central BC can show what may lie deep underground.
Geochemists Pim van Geffen and Britt Bluemel analyzed the chemistry of till (glacial gravels and clays) found at the surface to reveal what may lie deeper underground in Geoscience BC's Targeting Knowledge for Exploration and Knowledge (TREK) project area. The results can guide mineral exploration and land use decisions in the area.
Covering 24,000 km2 from Anahim Lake north and east towards Burns Lake, Vanderhoof and Williams Lake, the thick cover of till in the TREK area means that mineral exploration is difficult. The presence of rich deposits, such as the proposed Blackwater gold-silver mine, indicates there could be more deposits hidden below.
For the first project, called Enhancing Geochemical Precision by Analyzing the Clay Fraction in Till: Cost-Benefit Study from the TREK Project Area, British Columbia, the researchers specifically analyzed the clay-sized particles -- less than 0.002 millimeters -- and compared these results with previous analyses of particles less than 0.063 millimeters in size, to see if investing in additional sample preparation added value to the result.
"It is normally time-consuming and expensive to separate and analyze the clay-sized portion of a sample, but geochemical analysis of this fraction produces more precise assay results, increased trace-element contents, and enhanced anomaly-to-background contrast," said van Geffen.
"Given the demonstrated improvement in data quality, we recommend that analysis of the clay-sized fraction be given serious consideration before budget decisions preclude a potential discovery," added van Geffen.
Called Adding Value to Regional Till Geochemistry Data in Central BC through Exploratory Data Analysis, Bluemel and van Geffen applied exploratory data analysis (EDA) and other methods to the large TREK dataset of almost 3,000 till analyses. Powerful modern computing power is used to find trends in the data that would not have been evident in technologies used since EDA was introduced 50 years ago.
"The most efficient use of resources in mineral exploration is to add value to existing data products," said Bluemel, who identified trends in the new analysis that match to known deposits, such as Blackwater, and highlight new areas to look for buried mineralization.
Both projects used the same archives of till samples collected between 1994 and 2015 by various field teams from the British Columbia Geological Survey, Geological Survey of Canada and Geoscience BC.
To view the reports and maps, visit the project pages or view the information on Geoscience BC's Earth Science Viewer online mapping application.
Enhancing Geochemical Precision by Analyzing the Clay Fraction in Till: Cost-Benefit Study from the TREK Project Area, British Columbia
View 2016-036 project page View 2016-036 in Earth Science Viewer
Adding Value to Regional Till Geochemistry Data in Central BC through Exploratory Data Analysis
View 2016-037 project page View 2016-037 in Earth Science Viewer
About Geoscience BC
Geoscience BC is an independent, non-profit organization that generates earth science information in collaboration with First Nations, local communities, governments, academia and the resource sector. Our independent earth science enables informed resource management decisions. Geoscience BC gratefully acknowledges the financial support of the Province of British Columbia.