Sample: 90ADg-4


Sample ID: 90ADg-4 [1]
Station ID: 90ADg-4
AT Num:
Volcano: Churchill, Mt
Possible source: Churchill, Mt
Eruption: Mt Churchill White River East Lobe
Collector: McGimsey, R. G.
Date sampled: 1990-00-00
Sample type 1: Tephra Fall
Color:
Final unit:
Text Description: Summit pumice; loose accumulation of light-colored pumice, ranging in size from lapilli to blocks as much as 50 cm in diameter. Scattered throughout these tephra deposits, and locally abundant, are angular to subangular clasts of a variety of volcanic rocks, chiefly dark-colored, porphyritic and aphyric andesitic lava, and an occasional block of granitic rock and chlorite-rich amygdaloidal lava. The lithic fragments are similar in size to the pumice fragments and are interpreted to be rock ripped from the vent conduit walls during the explosive eruption(s). Also scattered throughout the tephra are clasts of yellow-orange pumice and lithics that apparently have been hydrothermally altered. Underlying this loose surface layer of pumice and lithic debris is a frozen zone of bedded tephra, consisting of pumice lapilli and blocks and exotic rock fragments disseminated in an ash matrix. White River Ash.
Sample Location:

References Cited

[1] Mount Churchill, Alaska: source of the late Holocene White River Ash, 1995

Richter, D. H., Preece, S. J., McGimsey, R. G., and Westgate, J. A., 1995, Mount Churchill, Alaska: source of the late Holocene White River Ash: Canadian Journal of Earth Sciences [Journal Canadien des Sciences de la Terre], v. 32, n. 6, p. 741-748.