| Text Description: |
A 2-cm thick, medium-grained tephra layer sampled 3 cm from the base of a 106 cm-thick coal bed (the T-seam of Barnes and Cobb, 1959). With the exception of FC11, the coal bed contains no other tephra or detrital material. About 40-50% poorly sorted, altered pumice fragments and bubble-wall shards mixed with organic material. The smaller shards are less altered than the larger pumice fragments. Five to 7% zoned and twinned plagioclase grains with remnants of unaltered glass fringes. Trace zircon, volcanic rock fragments with plagioclase microlites, stubby hornblende, quartz, and apatite. |