|Title||Biogeochemical surveys in the Bonaparte Lake area, south-central British Columbia|
|Author||Dunn, C E; Anderson, R G|
|Source||Geological Survey of Canada, Open File 6726, 2011, 42 pages; 1 CD-ROM, https://doi.org/10.4095/288001 (Open Access)|
|Links||Canadian Database of Geochemical Surveys, downloadable
|Links||Banque de données de levés géochimiques du Canada,
|Publisher||Natural Resources Canada|
|Media||CD-ROM; digital; on-line|
|File format||pdf; xls|
|Lat/Long WENS||-121.0000 -120.0000 51.7500 51.5000|
|Subjects||surficial geology/geomorphology; economic geology; geochemistry; biogeochemical surveys; biogeochemistry; vegetation; mineralization; mineral occurrences; mineral potential; glacial deposits; tills;
till samples; till deposits; gold; base metals; geochemical analyses; silver geochemistry; arsenic geochemistry; gold geochemistry; cadmium geochemistry; cesium geochemistry; chromium geochemistry; copper geochemistry; europium; mercury geochemistry;
potassium geochemistry; lutetium geochemistry; molybdenum geochemistry; sodium geochemistry; niobium geochemistry; nickel geochemistry; lead geochemistry; strontium geochemistry; tantalum geochemistry; terbium geochemistry; thorium geochemistry;
uranium geochemistry; zinc geochemistry; Quaternary; Cenozoic|
|Illustrations||location maps; photographs; plots; tables|
|Released||2011 03 18|
|Abstract||Exploration in the Interior Plateau of British Columbia is challenging because of the scarcity of outcrop, poor access, dense forests, and(or) glacial sediment or young basalt cover. Geophysical
signatures provide some guidance, but the ore-bearing lithologies in the survey area may not generate a distinctive geophysical signature or it may be masked by that of cover rocks. An additional exploration tool is needed.|
The chemical analysis
of tree tissues can provide insight to the composition of rocks concealed by overburden. The roots of trees can be perceived as natural drills that penetrate the substrate and extract metals from overburden, groundwater and locally bedrock. These
metals are translocated through the roots into the aerial tissues where they are sequestered in differing proportions according to tolerances to metals and(or) the metabolic requirements of an individual species of tree - in this case outer bark of
lodgepole pine and Engelmann spruce. Chemical signatures are usually subtle and data should be interpreted carefully.
During the course of a mapping programme in the summers of 2007 and 2008, bark and twigs from pine and spruce, and foliage from a
few western redcedar were collected on an opportunistic basis in the eastern Bonaparte Lake map area (NTS 92P 09 and 10). In 2009, a brief visit was made to collect more samples from an area of known PGE enrichments (Dum Lake) and to further
substantiate the elevated levels of REE detected during the earlier surveys.
More than 500 samples were collected and analyzed for 53 elements. A few were analyzed, also, for all the PGEs and REEs. Not all elements were detectable, and some were
too close to the detection limit to be usable as reliable data. However, data with good to excellent precision was obtained for more than 30 elements for all samples. Subtle multi-element trends and associations were sought in the data with the
objective of assisting in mapping the concealed bedrock and for providing focus for more detailed mineral exploration. A conclusion is that in the study area, for most elements, pine bark would be the preferred sample medium, because of its ability
to concentrate many elements to higher levels than spruce bark.
From this study, we conclude that the careful application of biogeochemical methods used in conjunction with other geological and geochemical data and concepts may assist in the
exploration for minerals in this environment by identifying spatially-related multi-element zones of subtle enrichments.