Research Interests

I have several currently active research projects, some of them funded by NSF. Below is a brief summary of past and currently active research projects. I am looking for students, so if interested please contact me by email about new projects in Central America and East Africa!

Selected current projects

 
 

Degassing from Erebus Volcano Antarctica


Erebus Volcano is a natural laboratory of magmatic processes and the ideal place to investigate magma degassing. Although the degassing processes from the active lava lake have been studied in detail over the past decades, comparatively little work has been done on the processes that affect flank degassing. Erebus is glaciated and is the site of ice towers and caves that are the surface expression of heat and volatiles escaping from the edifice into the atmosphere. Contrary to non-glaciated volcanoes where flank degassing is often diffuse and challenging to identify, the ice caves provide visible clues to the escape of gases and heat. Preliminary gas sampling during the 2012 field season in collaboration with Phil Kyle and Aaron Curtis (NMT), shows that gas compositions are dominated by a fractionated air component, with minor amounts of CO2, CH4 and H2. Significantly, the relative abundance of air-derived gases strongly suggests the presence of an aqueous phase below the surface. Into this liquid, magmatic- and air-derived gases dissolve. As the liquid moves away from the crater area, it cools, eventually freezes and, during this process, releases the gases through the ice caves. The goal of our project is to better characterize the liquid phase in terms of temperatures, gas contents and its effect on CO2 dissolution and degassing. The first field season for this project is in November-December 2015 where Tehnuka Ilanko and Tobias will sample ice cave gas emissions.
 

Volatile Emissions from Western Aleutian Volcanoes


In subduction zones volcanism is ultimately the result of volatile release from the subducting slab and partial melting of the mantle. Volatile concentrations of magmas affect melt density and viscosity, and influence eruption style. Volatile cycling has been studied at several volcanic arcs to date; however, none of which exhibit the complexity of the Aleutian Arc, Alaska. The Aleutian Arc is notable for significant along-strike variations in subduction features including convergence angle and rate, subducted sediment flux, composition of erupted products, and eruption frequency. These features make it an intriguing target for investigating the relationships among volatile cycling, subduction, and volcanic activity. The Aleutian Arc is also the location of over 36 persistently degassing volcanoes, and is one of the most poorly constrained arcs with respect to volatile outgassing. In collaboration with Dr. Taryn Lopez from the University of Alaska, Faibanks and with NSF-PIs from the Smithsonian Institution (Dr. Liz Cottrell) and the University of Rhode Island (Dr. Katie Kelly), as well as USGS-AVO scientists, we have successfully sampled and measured volatile emissions from the Western-most Aleutian volcanoes during the recent NSF-USGS-DCO expedition in September 2016. We are currently analyzing samples and interpreting the results. We also used the Thermo-Finnegan Delta Ray tunable diode laser to measured CO2 contents and carbon isotopes of volcanic plumes.
 

The interaction of magmatic volatiles, faults, and magmatism in the East African Rift Valley: insights from Northern Tanzania and Southern Kenya.


The goal of the project is to develop an integrative approach to understanding incipient and youthful rift zones developing in thick continental lithosphere by investigating a portion of the East African Rift system in northern Tanzania and southern Kenya. The development of these rifts is a fundamental plate tectonic process yet the driving forces behind rift initiation and early evolution are tenuously understood. By combining fieldwork, geophysics, geochemistry, and geochronology, we formulate a model for rift development and evolution that is integrated across disciplines and to capture multiple facets of the rifting processes. The results of the work will be applicable to rift zone development globally and can thus be integrated into existing plate tectonic models to provide a rationale for why continental breakup is possible. We now have completed two field seasons of sampling and diffuse degassing measurements in Kenya and Tanzania. Publications are forthcoming.
 

Volatiles in the groundwater systems of the Nicoya Peninsula, Costa Rica: tracking subduction zone gases from slab to surface.


Fluid flow through subduction zones is a fundamental process on Earth. As oceanic plates get subducted, water and other volatiles (i.e. CO2, N2) are released into the overlying mantle wedge. These fluids are the primary cause for the melting of the mantle and the production of water-rich magmas that cause explosive volcanic eruptions. In addition, volatiles are either efficiently recycled back to the atmosphere through subduction-related volcanoes (as is the case for N2) or are potentially carried into the deep mantle (as may be the case for CO2). The extent of volatile recycling in subduction zones, therefore, has significant bearing on the overall volatile composition of the mantle and the atmosphere. In this project, we are focusing on the Costa Rica subduction zone complex, and hope to produce a dataset of chemical and isotopic compositions of both gases and groundwaters with the aim of understanding details of volatile provenance, flux and temporal variability.