TOWARDS A COMPREHENSIVE GLOBAL MID-PROTEROZOIC CHEMOSTRATIGRAPHIC FRAMEWORK: CONTRIBUTIONS FROM NORTHERN BRITISH COLUMBIA

Our understanding of marine geochemical conditions during the early- and mid- Proterozoic suffers from a paucity of well-preserved and well-dated carbonate basins. A continuous carbonate record only reaches back to the early Neoproterozoic, inhibiting our ability to understand the long term evolution of Earth’s global geochemical cycles. It is imperative that to better understand changes in Mid-Proterozoic geochemical and biochemical cycling, we must explore and broaden our selection of basins as well as developed new methods to date and correlate sections. In particular, the development of a chemostratigraphic framework could set the foundations for a continuous carbonate record through the Mid-Proterozoic.

With that goal in mind, we have sampled and explored the Mid-Proterozoic lower Muskwa assemblage. Located in Northeast British Columbia, the basin is composed of over 6 km of generally unmetamorphosed, mixed carbonates and siliciclastics. The Lower Muskwa assemblage is thought to possibly be an equivalent to either the Purcell/Belt Supergroup or the Wernecke Supergroup. However its tectonic context is unknown and its age is poorly constrained to between 0.8 to 1.8 Ga. Our carbon isotope data find a limited range of -1‰ and +1‰, typical of Mid-Proterozoic carbonates. We also present a preliminary Sr chemostratigraphic framework, in addition to trace element and Rare Earth Element data.