Petrography and microanalysis

FEI Quanta 600 ESEM with EDXA and WDXA microanalysis system
Cryogenic sample preparation and handling system fitted to the ESEM
Reflected light optical photomicrograph showing a fan of graphite crystals; Snowdonia
Backscattered scanning electron photomicrograph (top) and scanning electron microscope-cathodoluminescence image (bottom) revealing complex growth zoning history in a zircon crystal.

The petrography and microanalysis section comprises specialist staff and laboratories providing expertise and a suite of microscopy and microanalytical techniques aimed at characterising, quantifying and interpreting the mineralogy, petrography, microstructure and microchemical properties of a wide range of materials relevant to geological, environmental and materials science applications. These include:

  • Optical petrography and ore microscopy: Optical microscopy techniques are used in the petrographic characterisation of mineral textures and fabrics of rocks, soils and unconsolidated sediments as well as anthropogenic materials (e.g. cements and wastes). Often a precursor for higher resolution scanning electron microscopy and electron probe microanalysis and is also extensively used in micropalaeontological and geomicrobiological studies.
  • Scanning electron microscopy: high-resolution scanning electron microscopy techniques are critical to many geosciences projects, including rock-water interaction; radioactive waste research; reservoir and cap rock characterisation for hydrocarbon reservoirs, aquifers, gas storage, geothermal energy; mineralization; environmental particles; soil fabric analysis; geomicrobiology; experimental petrology and micropalaeontology.
  • Electron probe micro-analysis: provides an understanding of the distribution of chemical components in geological and environmental materials to aid interpretation of their geochemical evolution. Electron probe microanalysis provides quantitative major and trace element information for individual minerals grains, with high spatial resolution down to 1 ┬Ám.
  • Cathodoluminescence microscopy: Both optical and SEM-based cathodoluminescence microscopy techniques are used in studying mineral growth fabrics and mineral cement stratigraphy with applications in sediment diagenesis, hydrothermal mineralisation, palaeohydrogeology and fractured rock characterisation. Imaging of zircon crystal growth zoning is an important pre-requisite for sample selection and interpretation of single zircon U-Pb age dating.
  • Autoradiography: digital and conventional autoradiography techniques are used to evaluate and quantify the distribution of natural and anthropogenic radionuclides in geological and environmental materials with important applications for radionuclide contamination, migration and behaviour.
  • Fluid inclusion microthermometry: Fluid inclusions are microscopic (<0.1 mm) droplets of liquid and/or gas trapped within crystals. Best known in quartz or calcite in hydrothermal vein deposits, they are also found in sedimentary rock cements, fossil amber and stalactites. Their analysis can provide valuable information about the conditions existing during mineral formation.


Please contact Dr Jeremy Rushton for further information.