New geochemistry from old drill holes at the Tom property, Macmillan Pass, Yukon

This paper presents new data from historical drill core and outcrop specimens from Macmillan Pass, Yukon. Whole rock lithogeochemical data are presented from analyses of core from three drillholes at the Tom property. The core covers intervals ranging from the Middle Devonian Road River Group (Sapper Formation) to the Upper Devonian Earn Group (Portrait Lake Formation–Fuller Lake Member) and includes the Macmillan Pass volcanic suite that occurs at the Road River–Earn Group contact. Samples were collected to characterize the depositional history of Middle–Upper Devonian fine-grained rocks in the region to aid with paleogeographical reconstructions, depositional models, improve age control and to aid in correlation of thick shale units. Baseline geochemical profiles and sedimentology for all fine-grained units indicate turbidity current deposition in a range of shelf to basinal settings and variable oxic to anoxic conditions. Additionally, eleven existing Middle Devonian conodont collections were re-examined to provide better biozone refinements and a tighter constraint of the contact between the Road River Group (Sapper Formation) and Earn Group (Portrait Lake Formation) to the Late Eifelian australis-ensensis biozones.