Halogens in Surface Exploration Geochemistry: Evaluation and Development of Methods for Detecting Buried Mineral Deposits

Key Researcher(s):  C. E. Dunn

Project ID:  2005-008

Key Research Organization(s):  Independent Consultant

Project Location:  Cariboo

Strategic Focus Area:  Minerals


Areas of Focused StudiesA significant part of central British Columbia has yielded few mineral occurrences due to a blanket of younger glacial materials concealing the rocks of interest. Development of an effective geochemical tool to detect concealed deposits would provide significant assistance to mineral exploration within these areas.

Volatile elements, such as the halogens (F, Cl, Br, I), are potential 'pathfinder' elements for locating mineral deposits. Halogens have been little-used in Canadian mineral exploration, partly because of a lack of easily accessible analytical methodologies. Their relationship to mineral deposits was investigated in this study and cost-effective analytical methodologies were developed for detecting low concentrations. The halogen data was examined in context of known deposits and conventional multi-element geochemical signatures. Investigations involved the geochemical response in vegetation and soils at three Cu-Au and Au-Ag deposits in central British Columbia - Mount Polley, QR, and 3Ts. Selected principal outcomes of the project:
  • The levels of labile halogens that can be expected in soils and vegetation from central BC have been defined;
  • Optimum cost-effective digestion and analytical procedures for determining labile components of halogens in soils and vegetation have been established.
  • Halogen signatures vary according to the nature of the mineralization. This indicates that each style of mineralization is likely to generate a different suite of positive halogen responses that have yet to be clearly defined; hence analysis for all four halogens is advisable.
  • Pine bark is the vegetation medium that best concentrates iodine, and gives good contrast for the other halogens.