Topics of current interest to me are the petrology and volcanology of the bimodal (basalt-rhyolite) suite in the western Snake River Plain, the petrology of differentiated mafic intrusions, and the geology of the Western Cascade Range in Oregon. Ongoing projects in these areas are described below; send me an e-mail if you would like more information about igneous petrology or volcanology at Boise State.
Phreato-magmatic Volcanism in the Western Snake River Plain: Between about 10 and 2 million years ago, at least two large fresh water lakes occupied much of the central and western Snake River Plain in Idaho and eastern Oregon. Both rhyolitic and basaltic magmas flowed into these lakes or erupted beneath them. During and after the draining of the most recent lake, rising basaltic magmas interacted with water saturated sediments resulting in a wide variety of phreatomagmatic structures and deposits. As a result, the central and western Snake River Plain contains one of the largest concentrations of hydrovolcanic and phreato-magmatic features in the United States. Scores of basaltic maars and tuff cones are well exposed along the Snake River Canyon, and several large rhyolitic lava flows show striking evidence for having flowed into standing water. Only a few of these hydrovolcanic centers have been mapped and studied in detail. Students interested in volcanological problems, particularly those involving magma-water interactions, are encouraged to inquire about possible thesis topics.
Recent student theses that focused on this topic include:
Intrusion Mechanisms, Magma Transport, and Flow Differentiation in Radial Dikes at Sinker Butte, Western Snake River Plain, Idaho (2007) Boise State MS Thesis by Kimberly Fowler
Stratigraphy and Evolution of the Sinker Butte Emergent Tuff Cone, Western Snake River Plain, Idaho (2004) Boise State MS Thesis by Brittany BrandStratigraphy and Petrography of Tuff Ring Deposits at Con Shea Volcano, Western Snake River Plain, Idaho (2002) Boise State Undergraduate Honors College Thesis by Heather Michaud
The Evolution of the Guffey Butte Tuff Cone Complex, Western Snake River Plain, Idaho (1999) Boise State MS Thesis by Chris Watson
Petrology of Western Snake River Plain Basalts: More than
100 basaltic volcanoes have been recognized in the western
Snake River Plain within 100 km of Boise. We are using the chemical compositions and
isotopic ratios of these basalts to better understand the magmatic evolution of
the western SRP rift system from its inception, around 10 million years ago,
through the most recent episode of volcanism, less than half a million years
ago. Student theses include:
Chemical Compositions and Sr, Nd and Pb Isotopic Ratios of Pleistocene Basalts in the Central Part of the Western Snake River Plain, Idaho (in progress) Boise State MS Thesis by Tiffany Rivera
Western Cascade Range: The Western Cascade province of Oregon contains a diverse assemblage of calcalkaline and tholeiitic volcanic and plutonic rocks ranging in age from Oligocene through Pliocene. The eroded volcanic centers exposed in this region provide some excellent opportunities to study continental arc volcanoes from the inside out. Our recent work here has focused on a complex of Miocene age rhyolitic ignimbrites and lava flows. Students interested in mapping volcanic terrains and working on problems related to magmatic differentiation and the origin of arc magmas are encouraged to inquire about specific thesis topics in this region (and sample fine dining, Western Cascade style). Student theses include:
Geology and Geochemistry of Volcanic Rocks of the Menagerie Wilderness, Western Cascades, Oregon (2002) Boise State MS Thesis by Geoffrey Cook
Graveyard
Point Intrusion: This roughly
sill-like gabbroic intrusion is located about 50 miles west of Boise in the
Sucker Creek area of eastern Oregon.
Although it is only 150 meters thick in its thickest part, the intrusion is remarkably
well differentiated and ranges in composition from olivine gabbro through ferrodiorite to
ferrodacitic granophyre. Our work to date has focused on the chemical and mineralogical
variations through several measured sections, but many questions remain unanswered about
the structure and evolution of this pluton. Potential student thesis projects
include the detailed mapping of structures and rock types throughout the intrusion
and a petrofabric study
to better understand the origin of laminated gabbros in the lower part of the
intrusion.
more about the Graveyard Point intrusion