Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 4 of 4
Full-Text Articles in Geology
Silica Sinter And The Evolution Of Hot Springs In The Alvord/Pueblo Valleys, Southeast Oregon, Usa, Leslie Allen Mowbray, Michael L. Cummings
Silica Sinter And The Evolution Of Hot Springs In The Alvord/Pueblo Valleys, Southeast Oregon, Usa, Leslie Allen Mowbray, Michael L. Cummings
Geology Faculty Publications and Presentations
Hot springs in the Alvord/Pueblo valleys in southeastern Oregon are analogous to Basinand- Range hydrothermal systems where heat source and permeable pathways are met through crustal thinning. Silica sinter deposition at Mickey Springs, Alvord Valley, predates the late Pleistocene high stand of pluvial Lake Alvord. At Borax Lake, Pueblo Valley, sinter deposition occurred during the Holocene. This study examines the evolution of springs at Mickey Springs, where three morphologies of sinter are present: (1) basalt clasts surrounded by sinter in interbedded conglomerate and sandstone, (2) pool-edge and aprons of sinter surrounding depressions (12–32 m diameter), and (3) quaquaversal sinter mounds …
A Simplified, Object-Based Framework For Efficient Landslide Inventorying Using Lidar Digital Elevation Model Derivatives, Michael D. Bunn, Ben A. Leshcinsky, Michael J. Olsen, Adam M. Booth
A Simplified, Object-Based Framework For Efficient Landslide Inventorying Using Lidar Digital Elevation Model Derivatives, Michael D. Bunn, Ben A. Leshcinsky, Michael J. Olsen, Adam M. Booth
Geology Faculty Publications and Presentations
Landslide inventory maps are critical to understand the factors governing landslide occurrence and estimate hazards or sediment delivery to channels. Numerous semi-automated approaches for landslide inventory mapping have been proposed to improve the efficiency and objectivity of the process, but these methods have not been widely adopted by practitioners because of the use of input parameters without physical meaning, a lack of transparency in machine-learning based mapping techniques, and limitations in resulting products, which are not ordinarily designed or tested on a large-scale or in diverse geologic units. To this end, this work presents a new semi-automated method, called the …
The Littlefield Rhyolite And Associated Mafic Lavas: Bimodal Volcanism Of The Columbia River Magmatic Province, With Constraints On Age And Storage Sites Of Grande Ronde Basalt Magmas, Brian Mcculloch Webb, Martin J. Streck, William C. Mcintosh, Mark L. Ferns
The Littlefield Rhyolite And Associated Mafic Lavas: Bimodal Volcanism Of The Columbia River Magmatic Province, With Constraints On Age And Storage Sites Of Grande Ronde Basalt Magmas, Brian Mcculloch Webb, Martin J. Streck, William C. Mcintosh, Mark L. Ferns
Geology Faculty Publications and Presentations
We present data that distinguishes the long-known Littlefield Rhyolite of eastern Oregon (northwestern United States) into two distinct, voluminous, Snake River–type, high-temperature rhyolite lava packages that erupted in short sequence overk.y., with minimum volumes of 100 and 150 km3 respectively, contemporaneous with flood basalt volcanism of the Grande Ronde Basalt phase of the Columbia River Basalt Group. Contemporaneity of rhyolites with flood basalts is exceptionally demonstrated within the Malheur Gorge by intercalated mafic units belonging to the Grande Ronde Basalt that are stratigraphically constrained by underlying and overlying Littlefield Rhyolite flows, and the underlying Dinner Creek Tuff (unit 1). Our …
Temporal And Crustal Effects On Differentiation Of Tholeiite To Calcalkaline And Ferro-Trachytic Suites, High Lava Plains, Oregon, Usa, Martin J. Streck, Anita L. Grunder
Temporal And Crustal Effects On Differentiation Of Tholeiite To Calcalkaline And Ferro-Trachytic Suites, High Lava Plains, Oregon, Usa, Martin J. Streck, Anita L. Grunder
Geology Faculty Publications and Presentations
Strongly bimodal, basalt-rhyolite volcanism of the High Lava Plains Province of Oregon followed the Middle Miocene flood basalts of the Pacific Northwest and extends to recent time. During the 8 m.y. of volcanism recorded in the central High Lava Plains, in western Harney Basin, three distinct mafic magmatic trends originate from primitive high-alumina olivine tholeiites (HAOT); they are tholeiitic, calcalkaline and ferro-trachytic. Tholeiitic basalts occur throughout the history and their compositions are derived by crystal fractionation while traversing the crust and mixing with evolved mafic magmas. Scavenging of apatite from crustal rocks and minor contamination with felsic melts accounts for …