Oxidized hydrous intermediate composition magmas are responsible for porphyry copper (Cu ±Mo ±Au) deposits and epithermal Au ore deposits formed globally in the shallow crust (Sillitoe, 2010; Seedorff et al., 2005). Recently, zircon geochemistry has been used to characterize both productive and barren intrusions associated with porphyry Cu-Au ore deposits....
The sheeted complex of the ~92 Ma Tenpeak pluton, in the Northern Washington Cascades crystalline core, forms a <1.5-km wide zone with a moderate, NE-dip at the SW margin of the pluton. Sheeted magmatic complexes, such as the one in the Tenpeak pluton, are common in plutons and represent examples...
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...
Motivated by observations of locally enhanced sea level variability near steep
topographic slopes in regions of strong time-mean flows, effects of zonal ridge topography
on zonal oceanic jet flow are investigated. Unstable wave properties and the
dynamics of eddy-mean flow interaction are evaluated as a function of topographic
geometry using...
Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their plutonic underpinnings, and the development of the continental crust.
The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is...
Distributed deformation in the backarc of Cascadia is complex. Off the west coast lies the Cascadia convergent margin. East of the plate boundary, clockwise rotation of the Oregon Coast Range block with respect to stable North America influences backarc deformation, causing extensional faults in southeast Oregon, contraction folding in southeast...
At least 105% nearly east-west extension of late Cenozoic age has been accommodated by down-to-the-east normal and oblique-slip faults in the central Wassuk Range. One northwest striking, right-lateral strike-slip fault probably contributes an additional component of WNW-ESE slip. Movement on the normal and oblique-slip faults in this area tilt the...
Magmatic sulfides from Yerington, Nevada, and Yanacocha, Peru, were analyzed by laser ablation-inductively coupled mass spectrometry (LA-ICPMS) and electron microprobe to determine copper, gold, and silver concentrations and ratios in order to examine the relationship to the metal content of related magmatic-hydrothermal ores. The magmatic sulfides occur in plutonic rocks...