A MAZAMA TEPHRA MARKER BED IN THE FRASER LOWLAND, BRITISH-COLUMBIA

Drill cores from the Fraser River delta and western Fraser River floodplain, British Columbia, reveal a widespread tephra marker bed within silty floodplain deposits. Isolated tephra layers have been noted in previous studies in the Fraser Lowland and have been assumed to be Mazama tephra (ca. 6800 BP). This note presents the results of the first attempt to systematically identify a number of tephra samples from this area, based on X-ray energy spectroscopic analysis of their chemical compositions and bracketing radiocarbon ages. The results confirm that the tephra bed is Mazama, a finding of considerable utility to future studies in this area.