Research
Understanding the behavior of volcanic systems is key to mitigating and predicting risks associated with future volcanic eruptions. My research aims to better our understanding of fundamental aspects of magmatic systems by combining detailed field observations, small-scale textural observations, and geochemical information measured on the eruptive products of subduction-related volcanoes. In my research, I study volcanoes with a holistic approach to better understand the various components of magmatic systems from melt generation, magma storage system, eruption processes, and the eruption records. Outlined below are are a few examples of my current interests.
Magma Storage Systems
The characterization of volcanic reservoirs location at depth and the properties of the reservoirs (geochemistry, thermal state, oxygen fugacity, etc.) and the connectivity with other intracrustal storage systems is of major importance in understanding historic patterns in eruptive behavior at arc volcanoes. Crustal reservoirs are a fundamental component of magmatic systems and understanding how magmas are stored within reservoirs located within different parts of the magmatic plumbing system, the nature of their interaction, and the timescales over which these processes operate are crucial for understanding the complex processes occurring during volcanic unrest leading up to passive or explosive eruptions. I currently study magmatic storage systems at Miyakejima volcano in the Izu-Bonin Arc of Japan and at Mentolat volcano of the Andean Southern Volcanic Zone of Chile.
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Petrogenesis of the southernmost Andean Southern Volcanic Zone, Chile
Understanding the cause of small-scale geochemical variability observed in the eruptive products of the four arc-front volcanoes of the southernmost Andean SVZ requires knowledge of primitive parental magmas being generated above the subducting and dehydraiting Nazca oceanic plate. To estimate the composition of primitive magmas of these four arc front volcanoes, olivine-hosted melt inclusion from explosively derived terpha are used to back calculate the composition of the primitive mamgas from these centers and to use those compositions to estimate melting parameters such as percent of mantle melting and mantle water content to better understand and compare these processes between these four arc-front volcanoes.
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Hudson Volcano, southern Chile
Hudson volcano is the southernmost center of the Andean SVZ and sits approximately 280 km to the east of the landward projection of the Chile Rise-Trench Triple Junction (CTJ). The CTJ is the point where the active spreading center, the Chile Rise, is currently being subducted beneath the South American Continent. Hudson was historically active in 1991 producing a large plinian eruption and previous work identified two large explosive eruptions of Hudson dated at ~4000 cal years BP (H2 event), and ~7,430 cal years BP (H1 event). My research led to the identification of a very large late-glacial eruption of Hudson volcano termed the Ho event. Comparison with the three previously documented large explosive Holocene Hudson eruptions (H1, H2, H1991 AD) suggests that Ho was larger, with an estimated tephra volume of >20 km3. This indicates that Hudson has generated ≥45 km3 of pyroclastic material in the last ~17,500 years, making it the most productive volcano in the southern Andes in terms of the total volume erupted since the beginning of deglaciation in the region.
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Tephrochronology of the southernmost Andean Southern Volcanic Zone
A portion of my research involves the identification and reconstruction of eruptive histories for a group of volcanic centers in the southernmost Andean Southern Volcanic Zone. The rates and magnitude of eruptions from this region was poorly understood due to large glaciers that inhibited the preservation of proximal outcrops shortly after and during deglaciation. However, lucustrine sediment cores ~100 km downwind of the volcanic arc preserve both large and small volcanic eruptions with exceptional stratigraphic control unrivaled by tephra outcrops and extend the record of volcanism from this region back into the late-Pleistocene. This research involves the identification, lithostratigraphic (terpha grain sizes and layer thickness) and petrographic description, and geochemical characterization to identify source volcanoes for tephras preserved in the lucustrine records and to estimate eruption magnitude, volume, and to construct a tepho-chrono-stratigraphic framework that can be utilized in other disciplines including paleoclimatologists, paleoecologiest and archeologists studying the region.
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Bentonite Tephrochronology of the basal Mancos Shale and Niobrara Formation, Colorado
The Niobrara Formation in the Denver Basin and the Niobrara age equivalent Mancos Shale in the Piceance Basin are important targets for unconventional oil and gas exploration and development. In the Denver Basin, the Niobrara is approximately 300 feet thick and consists of alternating zones of chalk-rich and marl-rich facies. In the Piceance Basin, the Niobrara age equivalent Mancos Shale ranges from 700 to 2500 feet thick and consists predominantly of clay-rich, silty shale with relatively thin, 20-40-foot intervals of marls and marly chalks , that have been the targets for recent horizontal drilling. However, except for highly diagrammatic cross sections showing a facies change from carbonate-rich strata in the east into silty shale in the west , no attempt has been made to correlate the Niobrara Formation in the Denver Basin to the Mancos Shale in the Piceance Basin. Although lithostratigraphic markers cannot be correlated with certainty from east to west, the Niobrara Formation in the Denver Basin and the Niobrara age equivalent Mancos Shale contain numerous bentonite beds that represent diagenetically altered ash deposits, or tephras, derived from large explosive volcanic eruptions. This project aims to geochemically fingerprint and correlate these ash deposits using the geochemistry of apatite and zircon phenocrysts from the Denver Basin to the Piceance Basin and, consequently, establish a chronostratigraphic framework for the Niobrara Formation and the age equivalent strata across the state of Colorado.
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