A5049463841- Paleontology and Stratigraphy of Fossils
- Geology and Paleoclimatology Research
- Calcium Carbonate Crystallization and Inhibition
- Groundwater and Isotope Geochemistry
- Insect and Arachnid Ecology and Behavior
- Clay minerals and soil interactions
- Iron oxide chemistry and applications
- Geochemistry and Elemental Analysis
- Radioactive element chemistry and processing
- Fossil Insects in Amber
- Hydrocarbon exploration and reservoir analysis
- Extraction and Separation Processes
- Material Properties and Applications
- Mine drainage and remediation techniques
- Minerals Flotation and Separation Techniques
- Neurobiology and Insect Physiology Research
- Methane Hydrates and Related Phenomena
- Advanced ceramic materials synthesis
- Geochemistry and Geologic Mapping
- Geological and Geochemical Analysis
- Bone Tissue Engineering Materials
- High-pressure geophysics and materials
- Geotechnical Engineering and Soil Stabilization
- Geological and Geophysical Studies
- Bauxite Residue and Utilization
Planetary Science Institute
2025
Washington University in St. Louis
2023-2024
University of Wisconsin–Madison
2018-2023
National Museum of Natural History
2021-2023
Smithsonian Institution
2021-2023
NASA Astrobiology Institute
2018-2021
Xiamen University of Technology
2021
Research Institute of Petroleum Exploration and Development
2020
China National Petroleum Corporation (China)
2020
Abstract Since the discovery of dolomite, numerous attempts have been made to understand its precipitation mechanism at Earth's surface conditions. One such relies on a relationship with microbial life, where laboratory synthesis experiments shown that specific organic molecules, as polysaccharides, exopolymeric substances and hydrogen sulphide can promote dolomite precipitation. Other mechanisms for precipitating focus abiotic chemical environments, adding dissolved silica, which lower...
The dynamics of trace metals at mineral surfaces influence their fate and bioaccessibility in the environment. Trace on iron (oxyhydr)oxide display adsorption–desorption hysteresis, suggesting entrapment after aging. However, desorption experiments may perturb coordination environment adsorbed metals, distribution labile Fe(III), aggregation properties, influencing interpretation metal fractions. In this study, we investigated irreversible binding nickel, zinc, cadmium to goethite aging...
Although calcareous anatomical structures have evolved in diverse animal groups, such been unknown insects. Here, we report the discovery of high-magnesium calcite [CaMg(CO3)2] armor overlaying exoskeletons major workers leaf-cutter ant Acromyrmex echinatior. Live-rearing and vitro synthesis experiments indicate that biomineral layer accumulates rapidly as mature, is continuously distributed, covering nearly entire integument, epicuticle catalyzes nucleation growth. In situ nanoindentation...
Abstract There is a great abundance of sedimentary dolomite in the Proterozoic and Lower Paleozoic, but examples primary are scarce Cenozoic. This discrepancy suggests poorly understood dramatic shift geochemical system that inhibited formation. Previous research on microbial-mediated formation demonstrated microbial activity could promote disordered precipitation through catalytic role polysaccharides. However, model cannot explain some Precambrian for which there no evidence origin. Here,...
New sources of rare earth elements (REEs) are needed to support a green energy transition. REEs adsorbed aluminum-rich clays in weathering deposits represent important resources, but the mechanisms responsible for their retention and ease extraction unresolved. Disordered coordination co-occurrence multiple species pose challenges investigating REE adsorption processes via established spectroscopic methods. In this study, we applied element-specific surface crystallography methods obtain new...
Calcium carbonate minerals, such as aragonite and calcite, are widespread in biomineral skeletons, shells, exoskeletons, more. With rapidly increasing pCO2 levels linked to anthropogenic climate change, minerals face the threat of dissolution, especially an acidifying ocean. Given right conditions, Ca-Mg carbonates (especially disordered dolomite dolomite) alternative for organisms utilize, with added benefit being harder more resistant dissolution. also holds greater potential carbon...
The substrate effect of mica and hematite on the nucleation crystallization calcite was investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), backscatter (EBSD) methods. On mica, we found, in absence Mg2+, substrates’ (001) surfaces with hexagonal pseudo-hexagonal two-dimensional (2-D) structure can affect orientation ~// (010) to be major interfacial relationship. hematite, did not observe frequent twinning relationship between adjacent gains, but often saw...
Protodolomite was detected in sediments from Great Salt Lake (GSL), Utah, U.S.A. that have no history of elevated temperature or pressure, conditions are thought to promote dolomitization sedimentary carbonates. abundant a non-oolitic sediment core the South Arm (SA) GSL at 26% salinity. also NA hand sample yet absent nearby oolitic locations likely receive allochthonous nutrients. not benthic photosynthetic mats SA. However, comprised aragonite with halite and minimal calcite; do form NA....
How dolomite [CaMg(CO3)2] forms is still underdetermined, despite over a century of efforts. Challenges to synthesizing at low temperatures have hindered our understanding sedimentary formation. Unlike calcium, magnesium's high affinity toward water results in kinetic barriers from hydration shells that prevent anhydrous Ca-Mg carbonate growth. Previous synthesis studies show adding low-dielectric-constant materials, such as dioxane, dissolved sulfide, and silica, can catalyze the formation...
ABSTRACT In contrast to the prevalence of dolomite [CaMg(CO 3 ) 2 ] in geological record, there are few instances recent formation. This discrepancy occurs despite supersaturation with respect many modern marine and lacustrine environments. Additionally, laboratory experiments have struggled precipitate at ambient temperatures (<40°C) even under highly saturated conditions. However, work has found dissolved silica be an effective catalyst for direct precipitation dolomite. To test this...
Research Article| June 05, 2018 Study of an Ordovician Carbonate with Alternating Dolomite–Calcite Laminations and Its Implication For Catalytic Effects Microbes On the Formation Sedimentary Dolomite Yihang Fang; Fang NASA Astrobiology Institute, Department Geoscience, University Wisconsin–Madison, Madison, Wisconsin 53706, U.S.A. Search for other works by this author on: GSW Google Scholar Huifang Xu Author Article Information e-mail: hfxu@geology.wisc.edu Publisher: SEPM Society Geology...
Abstract Oxidative weathering of pyrite plays an important role in the biogeochemical cycling Fe and S terrestrial environments. While mechanism occurrence biologically accelerated oxidation under acidic conditions are well established, much less is known about microbially mediated at circumneutral pH. Recent work (Percak‐Dennett et al., 2017, Geobiology , 15, 690) has demonstrated ability aerobic chemolithotrophic microorganisms to accelerate pH proposed two mechanistic models by which this...
Abstract Although calcareous anatomical structures have evolved in diverse animal groups, such been unknown insects. Here, we report the discovery of high-magnesium calcite [CaMg(CO 3 ) 2 ] armor overlaying exoskeletons major workers leaf-cutter ant Acromyrmex echinatior . Live-rearing and vitro synthesis experiments indicate that biomineral layer accumulates rapidly as mature, is continuously distributed, covering nearly entire integument, epicuticle catalyzes nucleation growth. In situ...
Abstract The Nitrogen (N) along with Carbon (C) isotopes, Rear earth elements (REEs) and trace (TEs) were detected in the lower Cambrian Yuertusi formation, Northwest Tarim Basin. Two sections of obvious isotopic elemental cycles have been investigated, which reflects sedimentary transformation from euxinic to upper anaerobic setting. extreme negative excursion kerogen δ 13 C emerged bottom layer silica shales. lowest value is up -37‰, similar global “Base” Cambrian. It could be inferred...
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