A5043063103- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- Glass properties and applications
- earthquake and tectonic studies
- Advanced NMR Techniques and Applications
- Clay minerals and soil interactions
- NMR spectroscopy and applications
- Crystal Structures and Properties
- Solid-state spectroscopy and crystallography
- Diamond and Carbon-based Materials Research
- Zeolite Catalysis and Synthesis
- Mineralogy and Gemology Studies
- Chemical Synthesis and Characterization
- Geochemistry and Geologic Mapping
- X-ray Diffraction in Crystallography
- Building materials and conservation
- CO2 Sequestration and Geologic Interactions
- Astro and Planetary Science
- Material Dynamics and Properties
- Metallurgical Processes and Thermodynamics
- Nuclear materials and radiation effects
- Geological and Geophysical Studies Worldwide
- Hydrocarbon exploration and reservoir analysis
- Advanced ceramic materials synthesis
- Advanced materials and composites
University of Bristol
2015-2024
Imperial College London
2017
Petrol (Poland)
1998-2015
Goethe University Frankfurt
2007
University of Bonn
1996-1998
University of Warwick
1991-1998
Colorado State University
1997
University of Manchester
1987-1994
University of Georgia
1992
Coventry (United Kingdom)
1991
A primary consequence of plate tectonics is that basaltic oceanic crust subducts with lithospheric slabs into the mantle. Seismological studies extend this process to lower mantle, and geochemical observations indicate return upper mantle in plumes. There has been no direct petrologic evidence, however, subducted crustal components from We analyzed superdeep diamonds Juina-5 kimberlite, Brazil, which host inclusions compositions comprising entire phase assemblage expected crystallize basalt...
Magma degassing processes are commonly elucidated by studies of melt inclusions in erupted phenocrysts and measurements gas discharge at volcanic vents, allied to experimentally constrained models volatile solubility. Here we develop an alternative experimental approach aimed directly simulating decompression-driven, closed-system basaltic magma equilibrium with H–C–O–S–Cl fluid under oxidized conditions (fO2 1·0–2·4 log units above the Ni–NiO buffer). Synthetic starting materials were based...
Forty-one diamonds sourced from the Juina-5 kimberlite pipe in Southern Brazil, which contain optically identifiable inclusions, have been studied using an integrated approach. The <20 ppm nitrogen (N) that is fully aggregated as B centres. Internal structures several revealed cathodoluminescence (CL) are unlike those normally observed lithospheric samples. majority of composed isotopically light carbon, and collection has a unimodal distribution heavily skewed towards δ13C ~ −25 ‰....
We performed laser-heated diamond anvil cell experiments on bulk compositions in the systems MgO–SiO2–H2O (MSH) and MgO–Al2O3–SiO2–H2O (MASH) that constrain stability of hydrous phases Earth's lower mantle. Phase identification by synchrotron powder diffraction reveals a consistent set relations for high-pressure, dense silicate D H. In MSH system phase is stable to ~ 50 GPa, independent temperature from 1300 1700 K. H becomes between 35 40 out reaction occurs at 55 GPa 1600 K with negative...
Crystalline silica (mostly cristobalite) was produced by vapor-phase crystallization and devitrification in the andesite lava dome of Soufriere Hills volcano, Montserrat. The sub-10-micrometer fraction ash generated pyroclastic flows formed collapse contains 10 to 24 weight percent crystalline silica, an enrichment 2 5 relative magma caused selective crushing groundmass. explosive eruptions has much lower contents (3 6 percent) silica. High levels cristobalite respirable raise concerns about...
The origin of sulfite (S4+) species in silicate glasses was evaluated using XANES at the S K-edge. Systematic investigations show that presence S4+ is an analytical artifact related to changes sulfur caused by irradiation with electron beam during EMPA or intense focused X-ray synchrotron analysis. data shown here indicate S2- and S6+ are only significant occurring synthesized under geologically relevant conditions.
Abstract Diamond‐hosted majoritic garnet inclusions provide unique insights into the Earth's deep, and otherwise inaccessible, mantle. Compared with other types of mineral found in sub‐lithospheric diamonds, garnets can most accurate estimates diamond formation pressures because laboratory experiments have shown that chemistry varies strongly as a function pressure. However, evaluation using compilation experimental data demonstrates none available empirical barometers are reliable for...
Eight glasses with molar Mg/2Al ≈ 1 in the system MgO-Al2O3-SiO2 have been studied by magic angle spinning (MAS) NMR spectroscopy. Using triple quantum (3Q) techniques we find evidence for significant concentrations of Al coordinated to five O atoms all glasses, proportion increasing decreasing Mg/Al and silica content. In = 1, up 6% is estimated be rather than four atoms. Calculations polymerization state these liquids made assuming that aluminum tetrahedral coordination charge balanced...