Bracketing ages for the formation of the Ring Creek lava flow, Mount Garibaldi volcanic field, southwestern British Columbia

Abstract

The Ring Creek lava flow, extending from Opal Cone, generally is considered to be the youngest volcanic feature in the southern section of the Mount Garibaldi volcanic field, southwestern British Columbia. An in situ stump dated 10 650 ± 70 BP (Beta 43865) obtained from a raised delta partially overridden by the lava flow indicates that the lava was extruded after ca. 10.7 ka. At the Skookum Creek and Mamquam River confluence, sediments eroded from the Ring Creek lava flow form an alluvial fan that contains charcoal dated 9360 ± 160 BP (Beta 38914), which indicates that the extrusion probably occurred before ca. 9.3 ka. Thus these radiocarbon ages bracket the age of the Ring Creek lava flow and indicate that volcanic activity in the southern section of the Mount Garibaldi volcanic field has been dormant since at least ca. 9.3 ka.