Present address: Department of Earth Sciences, Vancouver Island University, 900 Fifth Street, Nanaimo, BC, Canada, V9R 5S5.
A refined understanding of the paleoenvironmental history recorded at the Okanagan Centre section, an MIS 4 stratotype, south-central British Columbia, Canada
Article first published online: 11 DEC 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Journal of Quaternary Science
Volume 28, Issue 8, pages 729–747, November 2013
How to Cite
LESEMANN, J.-E., BRENNAND, T. A., LIAN, O. B. and SANBORN, P. (2013), A refined understanding of the paleoenvironmental history recorded at the Okanagan Centre section, an MIS 4 stratotype, south-central British Columbia, Canada. J. Quaternary Sci., 28: 729–747. doi: 10.1002/jqs.2665
- Issue published online: 11 DEC 2013
- Article first published online: 11 DEC 2013
- Manuscript Accepted: 2 SEP 2013
- Manuscript Revised: 30 AUG 2013
- Manuscript Received: 5 DEC 2012
- Geological Society of America Student Research. Grant Number: J.-E.L.
- Natural Sciences and Engineering Research Council (NSERC) of Canada Discovery. Grant Numbers: T.A.B., O.B.L., P.S. D. G.
- Cordilleran Ice Sheet;
- optical dating;
- Okanagan Valley;
The Okanagan Centre section is the stratotype for marine oxygen isotope stage (MIS) 4 sediments (Okanagan Centre Drift) in the southern interior of British Columbia, Canada. Previous work suggested that these sediments record two glacial and two interglacial cycles. This study reports on detailed sedimentological and geochronological investigations of lithostratigraphic units comprising the Okanagan Centre sequence, revealing successive deposition of subaqueous and subaerial outwash, a subglacial till and glaciolacustrine sediments during MIS 4. A limiting optical age of 113 ± 8 ka defines the base of this sequence. Sedimentological, paleopedological, optical dating and tephrochronological data from sediments near the middle of the sequence reveal soil development (MIS 3) in eolian sediments deposited on a river terrace overlying a deglaciated surface. Within these sediments, identification of Mt. St. Helens set C tephra suggest sedimentation between 50 and 35k 14C a BP. Optical dating corroborates the tephrochronology and suggests that this surface formed after ∼52 ± 7 ka. The record of MIS 2 glaciation is restricted to deglaciation, and overlies MIS 3 sediments above an unconformity possibly related to regional subglacial meltwater erosion. Eolian sediments containing Mt Mazama set O tephra (∼7.62k cal a BP) cap the sequence.