Mazama Member

The Mazama Member (informally, Mazama ash) is a large geologically recent volcanic ash deposit that covers portions of the U.S. states of California , Oregon, Washington (state) , Idaho, Montana, Nevada, Wyoming and Utah, as well as the Canadian provinces of British Columbia, Alberta and southwestern Saskatchewan. It was created by a massive explosive eruption of Mount Mazama ~6,900 years ago, during which it collapsed to create the caldera of Crater Lake.^{[2][|permanent dead link|dead link}}]}

To the south, the Mazama Ash overlies the older Bishop Tuff. To the north, it is overlain by the 508-year-old Wn Ash and the 3,400-year-old Yn Ash from Mount St. Helens, as well as the 2,400-year-old Bridge River Ash from the Mount Meager massif.^[2]

The ash is found in marine sediments off Oregon and Washington.^[3]

References

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