Lithostratigraphy of Devonian basinal mudrocks in frontier areas of northwestern Canada augmented with ED-XRF technique

Abstract

Rock materials from three Arctic wells drilled through Middle-Upper Devonian basinal mudrocks between 1969 and 1973 were surveyed with the energy-dispersive X-ray fluorescence tool (ED-XRF) Bruker Tracer IV-SD™. The logs of major oxides acquired from cuttings of two wells on Banks Island show that lithological signals can be seen through sample contamination, and therefore are capable of significantly increasing litho-chemostratigraphic resolution of old borehole logs. Survey of major and trace elements on a cored section through visually monotonous black shales of the Kugaluk N-02 well in northern mainland N.W.T. reveals new details, which allows for the correlation of this reference section with a better-studied succession in the central Northwest Territories, as well as the interpretation of anoxic horizons which correlate globally as the “Devonian anoxic events”. Despite shortcomings in accuracy, ED-XRF proves to be a rapid non-destructive technique to gain new information from old exploration wells in remote frontier areas.