Electron Microprobe Data for Tephra Attributed to Glacier Peak, Washington
| Autor: | Rose Okazaki, Charles R. Knowles, Henry W. Smith |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
010506 paleontology
geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Mineralogy Glacier Electron microprobe Cummingtonite 01 natural sciences Arts and Humanities (miscellaneous) Volcano Pumice General Earth and Planetary Sciences Phenocryst Tephra Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Quaternary Research. 7:197-206 |
| ISSN: | 1096-0287 0033-5894 |
| DOI: | 10.1016/0033-5894(77)90036-9 |
| Popis: | Reference samples of three prominent pumice units of Glacier Peak tephra collected east of the volcano within a distance of 100 km are similar petrographically to units described by earlier workers. Glass shards isolated from these samples were analyzed by electron microprobe to determine the content of Ca, Fe, and K. Resulting data, plus those published for two other references samples, provide a basis for attributing certain outlying tephra layers from 14 locations in eastern Washington, Idaho, Wyoming, and Montana to eruptions of Glacier Peak. Ten of the samples have properties of both Glacier Peak tephra and Mount St. Helens set J tephra, but proportions of Ca:Fe:K in glass shards indicate that 9 of the 10 outlying samples came from Glacier Peak, whereas one is assigned to Mount St. Helens set J. The remaining six outlying samples, all from southeastern Washington, contain cummingtonite phenocrysts and are chemically similar to some parts of Mount St. Helens tephra sets that are older than 12,000 BP. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|