A5071616849- Geological and Geochemical Analysis
- Paleontology and Stratigraphy of Fossils
- Geology and Paleoclimatology Research
- High-pressure geophysics and materials
- Marine and environmental studies
- Geochemistry and Geologic Mapping
- Geological Formations and Processes Exploration
- Methane Hydrates and Related Phenomena
- earthquake and tectonic studies
- Geological formations and processes
- Geological Studies and Exploration
- Planetary Science and Exploration
- Minerals Flotation and Separation Techniques
- Geochemistry and Elemental Analysis
- Mineralogy and Gemology Studies
- E-Learning and Knowledge Management
- Metallurgical Processes and Thermodynamics
- Geological and Geophysical Studies
- Geophysics and Gravity Measurements
- Ancient and Medieval Archaeology Studies
- Astro and Planetary Science
- Online Learning and Analytics
- Mining Techniques and Economics
- Maritime and Coastal Archaeology
- Global Maritime and Colonial Histories
Vanderbilt University
2010-2023
Lafayette College
2017-2023
Silicic magma systems are of great scientific interest and societal importance owing to their role in the evolution crust hazards posed by volcanic eruptions. MELTS is a powerful widely used tool study magmatic over wide spectrum compositions conditions. However, current calibration fails correctly predict position quartz + feldspar saturation surface temperature, pressure composition space, making it unsuitable silicic systems. We create modified optimized for systems, dubbed...
Terra Nova, 24, 227–232, 2012 Abstract Petrogenesis of silicic magmas in Iceland has fundamental significance for understanding the relative importance fractional crystallization mantle‐derived basalt and partial melting hydrothermally altered basaltic crust formation earliest continental crust. First results situ oxygen isotope investigation zircons large‐volume eruptive products three volcanoes (Askja, Torfajökull, Hekla) demonstrate diversity disequilibria long U–Th zircon pre‐eruptive...
The Miocene Peach Spring Tuff is a giant (� 640 km 3 dense rock equivalent) pyroclastic deposit that extensively exposed in the southwestern USA. Evidence from geochemical and textural analyses of bulk-rocks, glasses, accessory minerals (zircon, titanite, allanite, chevkinite, magnetite) outflow intra-caldera pumice clasts fiamme, combination with field observations rhyolite-MELTS modeling, suggests magma body was compositionally thermally zoned basal cumulate, it crystallized over...
Volcanic eruptions are driven by bubbles that form when volatile species exsolve from magma. The conditions under which depend mainly on magma composition, concentration, presence of crystals, and decompression rate. These all predicated the mechanism volatiles melt to bubbles. We critically review known or inferred mechanisms bubble formation in magmas: homogeneous nucleation, heterogeneous nucleation crystal surfaces, spontaneous phase separation (spinodal decomposition). propose a general...
Abstract Elucidating the compositions of melts from which Hadean zircons crystallized can provide insight into early crust construction. We calculated model using Ti-calibrated zircon/melt partition coefficients and trace element data for Hadean, Archean, possible analogue environments (e.g., rifts, hotspots, arcs) to constrain petrogenetic relationships. Model oceanic settings (mid-ocean ridges, arcs, Iceland) showed higher heavy rare earth (HREE) contents shallower middle REE (MREE)...
Breiðuvík and Kækjuskörð are two neighboring extinct eruptive centers in the East Fjords of Iceland. Together, they compose second-largest volume silicic rock country (after Torfajökull, an active volcanic system southern Iceland). We use ages compositions detrital zircon collected from rivers, Stóraá Krossá-Kækjudalsá, to investigate origins longevity magmatism at Breiðuvík-Kækjuskörð. Zircon populations catchments have identical median U-Pb dates (12.9 Ma), O isotopes (δ18O Vienna standard...
Iceland exemplifies the potential for generation of abundant silicic magma in absence mature island arc or preexisting continental crust. Zircon ages (U-Th and U-Pb) isotope compositions (Hf O), combined with whole-rock data (Nd, Hf, Pb), provide insight into petrogenesis mantle heritage these magmas. samples represent past 15 Ma Iceland's geologic evolution, geographic extent (marginal fjordlands to neovolcanic zones), modern tectonic settings (on-rift, propagating-rift, off-rift). The...
Stable Ti isotopes have been applied in the detrital sediment record to reconstruct bulk composition of Earth's continental crust due relationship between magmatic differentiation and isotopic compositions. However, no study has systematically evaluated influence provenance, physical, chemical weathering on sediments relative protolith they originated from. To test these processes compositions we investigate isotope 82 surface samples including loess, volcaniclastic rocks, river sediment,...
We have prepared thousands of future STEM faculty around the world to adopt evidence-based instructional practices through their participation in two massive open online courses (MOOCs) and facilitated in-person learning communities. Our novel combination asynchronous coordinated, structured face-to-face community experiences provides flexible options for graduate students postdoctoral fellows pursue teaching professional development. A total 14,977 participants enrolled seven offerings...
Abstract Bubbles in magmas drive explosive volcanic eruptions. The spatial distribution of bubble nucleation sites an ascending, decompressing, and supersaturating magma is one the primary controls on ash morphologies hazards. mechanism formation important because it ultimately determines bubbles fragmenting magma. initial a homogeneous problematical excessive surface tension pressure very small, nascent should exsolved volatiles back into melt. This thermodynamic barrier to viability...
Abstract We examine the morphology and chemistry of Vikrahraun basaltic eruption emplaced at Askja Volcano, Iceland, from Oct. 26–Dec. 17, 1961. The had three eruptive events, initiating with aʻa followed by alternating pahoehoe lava flow emplacement. determine that while is chemically homogenous (Fe/Mg = 1.9–2.2, 47–52 wt.% SiO2), it demonstrates transitions high to low viscosity morphologies. Aʻa flows have a total crystallinity (phenocryst microlite abundance area) ranging 85–100%, which...
The magmato-tectonic environment(s) of origin for Earth’s earliest crust are enigmatic and fiercely debated. Revealing the composition melts from which Hadean (>4.02 Ga) zircons crystallized might clarify conditions initial construction. We calculate model using Ti-calibrated zircon/melt partition coefficients (KdZrc(Ti)) published trace element data Archean zircons. same treatment is applied to possible analogue environments (MORB, Iceland, arcs, lunar), constrain potential petrogenetic...