I am pursuing research projects here in southern New Mexico and in the Cascade range of the pacific northwest. I am looking for students who would be interested in projects in the fields of volcanology and igneous petrology – please contact me if these projects, or others that we could develop, would be of interest!
1. Volatile contents and storage of rhyolitic magmas from the Organ Caldera, NM
The Organ Mountains, just east of Las Cruces, expose the plutonic and volcanic portions of the Organ Caldera. Caldera collapse occurred during large volume, explosive eruptions ~35 million years ago. Several thick ignimbrites are preserved in the southern Organ Mountains. Through analysis of quartz-hosted melt inclusions, we are investigating the volatile contents of these explosive eruptions, and when they can tell us about magmatic storage conditions (pressures, and thus depths). Additionally, the melt inclusions track changes in the melt composition over time, revealing magma chamber processes (convection, stratification, influxes of new magma) prior to eruption. My MS student just completed her research focused on the first- and last-erupted tuffs from the caldera. She found high volatile contents (<6.5 wt%) in melt inclusions from the first-erupted tuff and determined that the magma chamber was stored at upper crustal depths of ~4-9 km. Additionally, the chamber was convecting and well-mixed prior to eruption. My research group will continue working in the Organ caldera; and I will be looking for an MS student to start in the fall of 2018.
2. Along-arc trends in mafic magma geochemistry and the role of sediment subduction in the southern Cascades
This project, submitted by myself and Dr. Frank Ramos, recently received 3 years of NSF funding (starting July, 2015) to investigate along-arc trends in the compositions of primitive mafic magmas of the Cascade arc as well as the importance of subducted seafloor sediments to the magmas that are formed and erupted in the southern Cascades. Along-arc variations in trace elements and isotopes in primitive (>7 wt% MgO) mafic magmas illustrate a variable contribution of a subduction component (fluid +/- melt) along the arc. Further, the compositions of magmas erupted in the southern arc are indicative of perhaps an increased sediment contribution as well as a larger slab-melt component. Currently, the contribution of sediments in the southern subduction zone is not well known. Comparison of the geochemical compositions (particularly isotopes and trace elements) of primitive mafic magmas erupted in the southern arc to the seafloor sediments from the Gorda Plate will reveal the contribution of sediments to the sub-arc mantle wedge.
3. Blue Lake maar – a young phreatomagmatic eruption in the Oregon Cascades
I have been studying the deposits from a young mafic eruptive center in the Oregon High Cascades. This eruption began as a phreatomagmatic eruption; producing small surge deposits and ejecting large lithic blocks. The eruption than transitioned to a more typical magmatic phase, with abundant vesicular scoria deposited. I am working to map the deposits (isopach maps) and assess the componentry of the eruptive products in order to better understand this type of eruption and the potential hazards posed by future phreatomagmatic eruptions in the Cascades.
4. Monogenetic volcanism in the Potrillo Volcanic Field, NM
The Potrillo Volcanic Field contains numerous monogenetic volcanoes (cinder cones, shields, tuff rings and maars) that are relatively young (~17,000-80,000 ybp). I am interested in looking at the composition of magmas erupted at these centers, as even small monogenetic volcanoes often erupt multiple magma batches, or the magmas evolve during the eruption. I am also interested in the ascent rates of the magmas, as some of the deposits, like those at Kilbourne Hole, contain mantle xenoliths. Zoning of crystals can provide estimations of magma ascent rates.