Refining Late Pleistocene tephrostratigraphy in South-Central British Columbia with evidence of Mount St. Helens Set C correlations
Date
2025
Authors
Senilov, Nikolay
Bolton, Matthew
Huscroft, Crystal A.
Krezoski, Gillian M.
Norris, Sophie L.
Journal Title
Journal ISSN
Volume Title
Publisher
University Of Victoria
Abstract
South-central British Columbia (BC) hosts a rich archive of Late Pleistocene glacial and interglacial deposits, where multiple volcanic ash layers (tephra) serve as important chronological markers. Although the source volcanoes for most of these tephra remain unknown, previous studies have identified Mount St. Helens as a potential contributor. This work compiles and synthesizes existing geochemical, stratigraphic, and chronological data on Late Pleistocene tephra in south-central BC to refine current tephra descriptions and evaluate possible correlations with Mount St. Helens Set C. Qualitative comparisons of major oxide glass geochemistry show that several BC tephra (Okanagan Centre, Cherryville, Riggins Road, and Mission Flats) share compositional similarities with Mount St. Helens Set C. Additionally, mineralogical and chronological comparisons further support these correlations. Recent studies have also confirmed the presence of Mount St. Helens Set C tephra in the region, extending its known dispersal range into BC (Lesemann et al., 2013). By bridging local tephrostratigraphic records with the broader volcanic history of Mount St. Helens, this work helps support a more robust chronological framework for future studies of Late Pleistocene sediments in the region, thereby enhancing our understanding of glacial and interglacial dynamics and wider environmental change.
Description
Keywords
tephrochronology, Mount St. Helens Set C, quaternary geochronology, South-Central British Columbia