Integrated Ediacaran chronostratigraphy, Wernecke Mountains, northwestern Canada

Abstract

Terminal Neoproterozoic (Ediacaran, ca. 600–543 Ma) strata of the upper part of the Windermere Supergroup are well-exposed in the Mackenzie Mountains and the Wernecke Mountains of northwestern Canada. Windermere strata in the Mackenzie Mountains contain an exceptional Ediacaran biostratigraphic and isotopic (C and Sr) record, while the sequence stratigraphic record is subtle throughout this predominantly deep-water succession. Coeval strata in the Wernecke Mountains can be correlated with the succession in the Mackenzie Mountains on a formational level. In contrast to the deep-water setting of the Mackenzies succession, the Werneckes succession preserves a predominantly shallow-water succession amenable to detailed sequence stratigraphy. Integrated lithostratigraphy, chemostratigraphy, biostratigraphy and sedimentology partitions the Wernecke Mountains succession into five depositional sequences and constrains correlation with strata in the Mackenzie Mountains. The siliciclastic and carbonate sediments, deposited along the margin of the proto-Pacific Ocean, record accumulation in continental slope, neritic, and terrestrial paleoenvironments. Distinctive temporal chemostratigraphic and biostratigraphic attributes allow these strata to be correlated with other Ediacaran successions worldwide. Integrating sequence stratigraphy with these attributes is a robust, yet under-utilized correlation tool and is a step toward erecting a more detailed working Neoproterozoic chronostratigraphy.