High-resolution scanning electron microscopy is a key petrological and mineralogical tool. Detailed examinations are made of materials in a various formats, including rock chips, grain mounts, polished thin sections/mounts, slurries, liquids and emulsions. Information obtained then enables or contributes towards mineral identification, textural analysis, identification and evaluation fluid-rock- interaction and alteration, diagenetic phase identification and sequencing, fracture/fault rock studies and porosity characterisation.
BGS offer a range of SEM imaging techniques including:
Secondary electron imaging (SEI) for morphology and characterisation of mineral/material surfaces, and for biological and micropalaeontological studies
Backscattered electron imaging (BSEI) of polished sections to examine mineral phase distribution, compositional variations and relationships
Cathodoluminescence (CL) imaging of crystal growth fabrics and defects (compositional growth zoning, microfracturing, strain, growth / corrosion history)
Spectral and colour cathodoluminescence imaging
Scanning transmission electron microscopy (STEM)
Energy-dispersive (EDXA) and wavelength-dispersive (WDXA) X-ray elemental mapping of compositional variations within minerals
Quantitative modal analysis and image analysis of geological materials using EDXA elemental mapping and backscattered electron imaging
Facilities include both conventional high-vacuum SEM microscopy and environmental scanning electron microscopy (ESEM) for wet/cryogenic samples (e.g. ices, gas hydrates).
State-of-the-art FEI Quanta 600 ESEM, detectors for: (i) SEI under high vacuum; (ii) BSEI under high and low-vacuum; (iii) specialised large field detector for SEI under intermediate vacuum conditions (iv) specialised detectors for SEI and BSEI under very low vacuum / fully environmental conditions; (v) CL imaging; (vi) STEM and wet-STEM. Peltier-cooled cold-stage for ESEM operation at 0-100% RH and -40- +20°C.
LEO 535VP variable pressure SEM with secondary electron imaging, backscattered electron imaging, cathodoluminescence imaging and STEM. Conventional high- and low-vacuum (variable) modes.
State-of-the-art GATAN ALTO 2100 on-column cryogenic SEM preparation and sample transfer system with cryogenic cold stage facility, +50°C to -200°C
Fully-integrated Oxford Instruments INCA 450 EDXA and INCA Wave 700 WDXA X-ray microanalysis system. Fully calibrated for a wide range of elements from Na to U.
Oxford Instruments INCA software for qualitative and fully-quantitative EDXA and WDXA microanalysis, microchemical X-ray elemental mapping, phase mapping and modal analysis.
GATAN MonoCL3 spectral CL spectrometer and imaging system. CL spectral analysis, specific wavelength and colour CL imaging.
The Keyworth scanning electron microscopy laboratory plays a major role in projects spanning a wide range of the BGS science programme, including:
Evaluation of fluid-water interaction and mineral alteration in experimental materials.
Examination of nanoparticles as tracers for gas and groundwater flow pathways.
Characterisation of lithologies and engineered barrier materials intended for radioactive waste disposal and carbon dioxide capture/storage.
Natural analogue studies for radioactive waste management and carbon capture/storage.
Research on mineral sequestration of carbon dioxide.
Evaluation of diagenetic evolution of hydrocarbon reservoirs and aquifers, and to understand the controls on reservoir and aquifer properties.
Staff and facilities are also in constant demand for direct consultancy analysis and interpretation by external clients including: oil, mineral and mining companies; engineering and utility companies; consultancies; university departments and local authorities