A5091454535- Nuclear materials and radiation effects
- Geological and Geochemical Analysis
- Glass properties and applications
- Radioactive element chemistry and processing
- Building materials and conservation
- High-pressure geophysics and materials
- Clay minerals and soil interactions
- CO2 Sequestration and Geologic Interactions
- Geochemistry and Geologic Mapping
- Geology and Paleoclimatology Research
- Calcium Carbonate Crystallization and Inhibition
- Luminescence Properties of Advanced Materials
- Astro and Planetary Science
- Planetary Science and Exploration
- Mineralogy and Gemology Studies
- Pleistocene-Era Hominins and Archaeology
- Nuclear Materials and Properties
- Concrete and Cement Materials Research
- Chemical Synthesis and Characterization
- Cultural Heritage Materials Analysis
- Advanced Condensed Matter Physics
- Mine drainage and remediation techniques
- Inorganic Chemistry and Materials
- Crystal Structures and Properties
- earthquake and tectonic studies
University of Bonn
2015-2024
Johannes Gutenberg University Mainz
2020
Folkwang University of the Arts
2019
University of Siegen
2019
University of Münster
2003-2012
Universität Hamburg
2000-2012
Kumamoto University
2008
Institute for High Pressure Physics
2008
Alexandru Ioan Cuza University
2008
Museum am Rothenbaum
2001-2003
Research Article| February 01, 2007 Re-equilibration of Zircon in Aqueous Fluids and Melts Thorsten Geisler; Geisler 1Institut für Mineralogie, Universität Münster Corrensstr. 24, 48149 Münster, Germany E-mail: tgeisler@nwz.uni-muenster.de Search for other works by this author on: GSW Google Scholar Urs Schaltegger; Schaltegger 2Université de Genève, Section des Sciences la Terre Rue Maraîchers 13, 1205 Switzerland Frank Tomaschek Author Article Information Publisher: Mineralogical...
Nations using borosilicate glass as an immobilization material for radioactive waste have reinforced the importance of scientific collaboration to obtain a consensus on mechanisms controlling long-term dissolution rate glass. This goal is deemed be crucial development reliable performance assessment models geological disposal. The collaborating laboratories all conduct fundamental and/or applied research modern materials science techniques. paper briefly reviews vitrification programs six...
We present the results of a series hydrothermal experiments on grains from two partially metamict zircon samples Sri Lanka in temperature range 350 to 650 °C and with different solutions (2 M AlCl3, 2 CaCl2, pure H2O, multi-cation solution). Under these conditions, sharply bounded reaction fronts penetrated into developed complex lobate rim structures that resemble found natural systems. The zones are characterized by marked increase cathodoluminescence intensity, decrease back-scattered...
Abstract The chemical and structural alteration of metamict zircon crystals from a 619 ±17 (2σ) Ma old, posttectonic granite in the southern part Eastern Desert, Egypt was studied. show simple oscillatory growth zones with metamictization–induced fractures, which provided pathways for fluid infiltration. Electron ion microprobe analyses reveal that metamict, i.e. U Th–rich, areas are heavily enriched Ca, Al, Fe, Mn, LREE , water species, have lost Zr Si as well radiogenic Pb. These changes...
Oligoclase and labradorite crystals have been experimentally replaced by albite in an aqueous sodium silicate solution at 600°C 2 kbars. The replacement is pseudomorphic characterised a sharp chemical interface which progresses through the feldspar while preserving crystallographic orientation. Reaction rims of albite, up to 50 μm thick, can be readily achieved within 14 days. Re-equilibration plagioclase 18O-enriched sodium- silica-bearing results oxygen isotope redistribution framework...
Sponges are probably the earliest branching animals and their fossil record dates back to Precambrian. Identifying skeletal structure composition is thus a crucial step in improving our understanding of early evolution metazoans. Here, we present discovery 505–million-year-old chitin, found exceptionally well preserved Vauxia gracilenta sponges from Middle Cambrian Burgess Shale. Our new findings indicate that, given right fossilization conditions, chitin stable for much longer than...
Significance We document organic matter encapsulated in rock clasts from a oceanic serpentinite mud volcano above the Izu–Bonin–Mariana subduction zone (Pacific Ocean). Although we cannot pinpoint exact origin of matter, chemical analysis constituents resembles molecular signatures that could be produced by microbial life deep within or below volcano. Considering known temperature limit for life, 122 °C, and forearc geotherm where such volcanoes are located, estimate exist as ∼10,000 m...
Research Article| July 01, 2016 Control of silicate weathering by interface-coupled dissolution-precipitation processes at the mineral-solution interface Encarnación Ruiz-Agudo; Ruiz-Agudo * 1Departamento de Mineralogía y Petrología, Universidad Granada, 18071 Spain *E-mail: encaruiz@ugr.es Search for other works this author on: GSW Google Scholar Helen E. King; King 2Department Earth Sciences, Utrecht University, 3584 CD Utrecht, Netherlands Luis D. Patiño-López; Patiño-López 3Centro...
Leucite and analcime have open framework aluminosilicate structures, where ion exchange by cation substitution has been previously used to explain the replacement of one phase another. Using 18O-enriched NaCl solutions in hydrothermal reactions run-product analyses using scanning electron microscopy, infrared Raman spectroscopy, time-of-flight secondary mass spectrometry, we show that leucite is not a solid-state reaction involving volume diffusion. Textural features such as nano-pores...
The application of the Hf isotope composition zircon as a geochemical tracer requires preservation Lu-Hf systematics within individual grains. We performed hydrothermal experiments on self-irradiation-damaged to test whether alteration would affect its isotopic composition. Severely radiation-damaged from Sri Lanka was reacted in either Teflon reactors or gold capsules at 200 °C (1080 h, autogeneous pressure), 400 (120 1 kbar), and 600 (72 kbar) M HCl-0.2 HF solution that spiked with 300 ppm...
Abstract Borosilicate glasses are currently used for the immobilization of highly radioactive waste and materials choice many biomedical research industries. They metastable that corrode in aqueous solutions, reflected by formation silica-rich surface alteration layers (SAL). Until now, there is no consensus scientific community about reaction transport mechanism(s) rate-limiting steps involved SALs. Here we report results multi-isotope tracer ( 2 H, 18 O, 10 B, 30 Si, 44 Ca) corrosion...
Neutralization of acidic fluids by means fluid-olivine interactions is important in volcanic environments and has been proposed as a practical scheme for the neutralization sulfaterich fluids. To understand interaction olivine with highly we have reacted whole crystals dunite cube different sulfuric acid solutions at temperatures ranging from 60-120 °C. Reaction 2 3.6 M concentrations produced layered amorphous silica pseudomorph original grain. The mechanism pseudomorphic replacement was...