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Full-Text Articles in Physical Sciences and Mathematics
Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson
Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson
Dissertations and Theses
Glass Buttes, a Pliocene silicic volcanic complex within the High Lava Plains province of Oregon, was erupted approximately 5.0 to 5.8 million years ago. Geologic mapping revealed that the eastern portion of the complex is underlain by rhyolitic glass domes, flows and rare pyroclastic flows. Basalt flows are interlayered with and onlap the silicic glass. Younger basalt flows, erupted from local vents, overlie silicic glass and onlapping basalts.
The eastern end of Glass Buttes is hydrothermally altered at the surface; a weak geothermal anomaly coincides with the altered areas. Alteration, localized by northwest trending normal faults, occurs primarily as opalite …
Tiltmeter Analysis Of Mount St. Helens, Skamania County, Washington, Edward Charles Brown
Tiltmeter Analysis Of Mount St. Helens, Skamania County, Washington, Edward Charles Brown
Dissertations and Theses
Mount St. Helens returned to an active eruptive state March 20, 1980. Since then explosive and dome building eruptions have caused major topographic changes to the mountain and surrounding drainages. Monitoring of the southern side of the mountain by six tiltmeters at distances between 6 km and 12 km was conducted during the period of July 1, 1980 to December 31, 1980. Records obtained from the tiltmeters were analyzed and compared to data from precision geodetic surveys.
Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters
Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters
Dissertations and Theses
Over 1150 m of middle to late Eocene nonmarine arkose, lithic arkose, mudstone, and siltstone, referred to here as the Chambers Creek beds, are int~r.stratified with, and overlain by over 1600 m of late Eocene-Oligocsne(?) andesitic volcaniclastic and subordinate volcanic rocks assigned to the Ohanapecosh Formation, in a dissected structural high in the southern Washington Cascade Range, about 18 km south-southeast of the town of Packwood.
Quaternary Volcanology Of The West Crater-Soda Peaks Area, Southern Washington Cascade Range, David R. Polivka
Quaternary Volcanology Of The West Crater-Soda Peaks Area, Southern Washington Cascade Range, David R. Polivka
Dissertations and Theses
The West Crater-Soda Peaks area covering about 100 km is located 35 km southeast of Mount St. Helens in southern Washington State. It is one of several Quaternary monogenetic High Cascade volcanic centers overlying the Ohaaapecosh Formation of the Western Cascade Group and interstratified glacial till.These volcanic centers are the most westerly of the range.