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Full-Text Articles in Physical Sciences and Mathematics
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 …
Variability In The Mass Flux Of The Ross Sea Ice Streams, Antarctica, Over The Last Millennium, Ginny Catania, Christina L. Hulbe, Howard Conway, Ted A. Scambos, C. F. Raymond
Variability In The Mass Flux Of The Ross Sea Ice Streams, Antarctica, Over The Last Millennium, Ginny Catania, Christina L. Hulbe, Howard Conway, Ted A. Scambos, C. F. Raymond
Geology Faculty Publications and Presentations
We synthesize previously published remote-sensing observations, radar data and model output to obtain a ~1000 year ice flow history for the Siple Coast ice-stream system in West Antarctica to investigate the timing and magnitude of changes in mass flux. The synthesized history shows significant short-term variability in ice-stream shear margin and grounding line position due to internal variability of the coupled system. The chronology highlights the interplay between adjacent ice streams, which implies that the behavior of any individual ice stream should not be examined in isolation. Furthermore, individual events cannot be fully interpreted without an understanding of the broad-scale, …