Project: Late Cretaceous to Eocene Tectonic and Metallogenic Evolution of the Nechako Region, Central British Columbia: Insights from Volcanic Stratigraphy and Structural Framework Reconstructions
Episodic but widespread magmatic activity occurred along the Canadian Cordillera from the Late Cretaceous to the Miocene under a post-accretion, dominantly extensional tectonic setting. As a result, thick, discontinuous sequences of Eocene volcanic rocks cover over 15,000 km2 of the Nechako region of central British Columbia. They unconformably overlie Jura-Cretaceous basin clastic sedimentary rocks and are extensively masked by Neogene subaerial Chilcotin flood basalts and Quaternary glacial sediments. These Eocene volcanic rocks and associated structures record an important chapter of the magmatic and tectonic evolution of the Canadian Cordillera and constitute the focus of this study.
In this project, characterization of the nature, thickness and structural framework of Eocene volcanic rocks will provide new insights into the geology of central British Columbia and into the tectonic evolution of the Canadian Cordillera in the Cenozoic. Field mapping techniques combined with geochemical and geochronological analyses will aim at characterizing lithologies, textures and volcanic facies of Eocene volcanic rocks. An improved stratigraphic model based on the identification of mappable units will be proposed for the Eocene period in the Nechako region. A structural framework together with an Eocene thickness model will clarify controls on the distribution, extent and thickness of Eocene volcanic rocks. This structural framework will facilitate identification of structures like calderas, pull-apart basins, pre-Eocene basement structures and structures reactivated during the Eocene.
Outcomes of this study will help assessing the metallogenic potential of Eocene volcanic rocks in the Nechako region. In particular, there will be a focus at clarifying relationships, differences and structural controls on Eocene versus Late Cretaceous Au-Ag epithermal-style deposits hosted in felsic fragmental volcanic rocks. In addition, Jura-Cretaceous basin rocks have some hydrocarbon potential, but their stratigraphy has been extensively complicated by Eocene thermal and structural overprinting. Structural and tectonic models proposed in this study will allow improved reconstruction of the basin architecture and better identification of pre‐Eocene hydrocarbon bearing features.