Event Name : Augustine Tephra M
|Start: 1000 (± 100 Years) || Years BP C-14 (raw) || |Description:
From Waitt and Beget (1996): "Exposed on the steeply eroded sides of three south-side inlier kipukas at altitudes 250-700 m are 8-10-m sections comprising several beds of pumiceous and lithic pyroclastic-fiow deposits interbedded with many beds of loose, sorted pumiceous fall deposit. The uppermost pumiceous fall beds probably correlate with tephras M, C, and perhaps with other tephra beds of the coastal sections, though ambiguous field character and ambiguous chemical data make such correlations tenuous. Yet a radiocarbon age of about 2160 yr B.P. (table 2 [in original text]) from the upper midsection (below the upmost few tephra layers) at the eastmost such section supports the tenuous correlation."
From Waitt and Beget (2009): "Of the two youngest coarse tephras, M drifted south and B strongly northeast (fig. 7 [in original text])."
"Glass separates of tephras C and M are chemically nearly identical-as close as replicate microprobe analyses of either tephra C or tephra M alone. Correlation of tephras between separated localities is thus mainly by field stratigraphy, in some places strengthened or augmented by the microprobe data."
"On the south and west, tephra M seems everywhere much thicker than tephra B."