About 7,000 years ago two major tephra-falls blanketed the
Pacific Northwest in volcanic ash. These two tephra-falls, identified
as the Llao and climatic tephra-falls, were a part of the eruptive
events that led up to the collapse of Mount Mazama to form Crater Lake
in the southern Oregon Cascades.
The...
Crater Lake, located in the southern Cascade mountains of Oregon, is the seventh deepest lake in the world. Unlike a majority of the deepest lakes in the world, found in continental rift valleys, Crater Lake is in the caldera of a volcano. For the young at heart and mind, those...
During the Pleistocene, an andesitic volcano named Mount
Mazama grew to a probable elevation of 3000 meters in south-
central Oregon. Near the end of the Pleistocene, three diverse
magma types appeared in the eruptive products associated with Mount
Mazama: l)High-alumina basaltic andesite magma associated with an
early plateau and...
This study is an effort to characterize the magma sources, plumbing system, and eruptive behavior of Mount Hood, a low-explosivity recharge-dominated volcano in the Oregon Cascades. The three manuscripts in this dissertation make use of melt inclusion data, phenocryst compositions, and whole rock petrology and geochemistry to build a schematic...