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Spatial And Temporal Evolution Of The Volcanics And Sediments Of The Kenya Rift, Alexandria L. Guth
Spatial And Temporal Evolution Of The Volcanics And Sediments Of The Kenya Rift, Alexandria L. Guth
Dissertations, Master's Theses and Master's Reports - Open
New volumetric and mass flux estimates have been calculated for the Kenya Rift. Spatial and temporal histories for volcanic eruptions, lacustrine deposition, and hominin fossil sites are presented, aided by the compilation of a new digital geologic map. Distribution of volcanism over time indicates several periods of southward expansion followed by relative positional stasis. Volcanism occurs throughout the activated rift length, with no obvious abandonment as the rift system migrated. The main exception is a period of volcanic concentration around 10 Ma, when activity was constrained within 2° of the equator.
Volumes derived from seismic data indicate a total volume …
A Petrologic Study Of The Teanaway Basalt: Eocene Slab Window Volcanism In Central Wa, Liz Roepke
A Petrologic Study Of The Teanaway Basalt: Eocene Slab Window Volcanism In Central Wa, Liz Roepke
Summer Research
The Teanaway Basalt (TB) includes subaerial basalt to andesite flows, mafic to felsic tuffs, and rhyolite domes in the Central Cascades of Washington State. These volcanics overlie the extensive ~47 Ma Teanaway Dike Swarm (TDS) that cuts the underlying Swauk Formation. Samples were collected from 3 main localities: Easton Ridge (ER) in the west, Liberty Ridge (LR) in the east, and the Middle Fork of the Teanaway River (MF) in the center.
The bimodal TB consists predominantly of basaltic andesite and andesite (45.3–63.1 wt% SiO2) with subordinate rhyolite (75.9–79.4 wt% SiO2). The mafic rocks classify as …