The southeastern Cuyama Valley is located in the southern Coast
Ranges, west of Bakersfield, California. Subsurface geologic mapping
using data from 62 prospect wells was integrated with surface mapping
to determine the depositional and deformational history of this part
of the Neogene Cuyama basin.
The northwest-trending Russell fault system was...
The significance of geology is commonly overlooked by the general public and underrepresented in free-choice learning environments including national parks that exhibit spectacular examples of geological features and processes. Parks are a major contributor to public learning, and a key way to teach how geology influences many aspects of our...
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Robert J. Lillie
The significance of geology is commonly overlooked by the general
Andesitic and rhyolitic magmatism was active during the mid-
Tertiary (Early Miocene) of the Ash Peak area, southeastern Arizona.
Andesitic magmas of similar composition both preceded and followed the
low- and high-silica rhyolitic magmas. The changes from andesitic to
rhyolitic and back to andesitic volcanism is postulated to be the...
Inheritance from pre-existing mantle domains and fluid and melt contributions from active subduction together produce the geochemical signatures of mantle-derived arc basalts. In this context, this work evaluates the evolution of Cascadia mantle sources by documenting the isotopic and compositional characteristics of primitive basalts along a transect across the Eocene-Oligocene...
The 2-ka eruption of Misti volcano produced voluminous flowage deposits and a wide-spread tephra-fall deposit. The flowage deposits form large terraces within channels draining the south side of the volcano. All the channels drain into the city of Arequipa. Arequipa's city center is ~16 km from the summit of the...
The eruptive history of the Quaternary Cascades arc has been relatively well characterized. However, much less is known about the frequency and sizes of explosive eruptions produced by earlier stages of the arc. The Late Neogene Deschutes Formation of Central Oregon preserves a remarkable record of heightened pyroclastic activity during...
Three broadly interrelated problems of critical significance to the proper interpretation of melt inclusion (MI) data are addressed in this thesis. The first issue, the petrogenesis of anorthitic plagioclase phenocrysts in MORB lavas, has relevance due to the presence of numerous MI in many high-An feldspars. This problem was addressed...
Decades of experimental work has illustrated the high degree to which the partitioning of most elements is dependent on phase composition, temperature and pressure. In order to quantitatively describe clinopyroxene partitioning it is required to derive expressions using theoretical constraints calibrated with experimental data.
The experimental database available for such...