Summary of field activities in the western Liard Basin, British Columbia

Abstract

International audienceThe second and final year of a regional bedrock mapping program within the Toad River map area (NTS 094N) was completed in 2012. The program will result in three-100 000 scale maps of the northwest, northeast and southeast quadrants of 094N and with four 1:50 000 scale maps covering the southwest quadrant. Surface samples were also collected for Rock Eval™, reflective light thermal maturity and apatite fission-track analysis. Cuttings from several petroleum wells in the map area were also sampled for Rock Eval analysis and vitrinite reflectance. Composite sections of the Besa River Formation were measured in the southern Caribou Range and along the Alaska Highway, south of Stone Mountain. Approximately 170 m of the Besa River Formation were measured in three separate sections in the southern Caribou Range. Lithological, gamma-ray spectrometry and lithogeochemical data are similar to those observed in other sections of the formation, suggesting similar depositional conditions within the western Liard Basin. Changes in abundances of several trace elements, particularly, V, Mo, Ba and P, suggest variations in redox conditions during the deposition of the formation. Radiolarian and conodont fragments from the upper part of the section in the Caribou Range indicate a mid-Tournaisian age. Characteristics of the lower Besa River Formation observed along the Alaska Highway south of Stone Mountain are similar to the Evie member of the Horn River Formation