School of GeoSciences

School of GeoSciences

Sample Requirements

Please read the information on Tephra Sample Preparation Procedures (PDF) and the information on epoxy resins found on the SIMS page.

  • For quantitative analysis the specimens must be flat, well polished and as free from surface voids as possible.

    Final polishing should use 0.25 micron abrasive
    Samples with porosity should be vacuum-impregnated with resin to fill void space

  • Samples must be cohesive, so as not to shed particles whilst in the SX100
  • Samples must be in a format compatible with the SX100 sample holders. Permitted formats are:
  • Thin sections: 45-48mm long, up to 25mm wide, 1mm thick with up to 0.5mm thick polished sample above the glass slide
    Disks: 25.5mm or 29.5mm diameter, thickness 5-25mm
    It may be possible to accommodate other formats - please discuss details with Chris Hayward
    Lakeside, Canada Balsam and styrene-based resins must not be used for preparation.

  • Samples need to be coated prior to analysis with a thin film of carbon. This is done at Edinburgh.
  • Samples should arrive at the laboratory 2 days before the EPMA session for coating
    Samples must be cleaned after polishing and before carbon coating to remove traces of abrasive particles and lubricants. This is done at Edinburgh using petroleum spirit.

  • Where Facility clients lack their own sample preparation facilities, it can be possible for samples to be prepared for EPMA at Edinburgh, subject to availablility of the Edinburgh preparation facility. Samples must be submitted AT LEAST 5 WEEKS IN ADVANCE OF THE FIRST DAY OF EPMA.

    A method for the preparation of micro- and cryptotephras, developed by Mike Hall at Edinburgh, will shortly be published in the Geological Society Special Publication on Marine Tephras (Hall and Hayward, in press).

    Please discuss any queries related to sample preparation or format with Chris Hayward well in advance of your scheduled EPMA booking

When analysing micro- and cryptotephras and a high proportion of mineral or biogenic silica matter is present, it may be necessary to use methods, such as heavy liquid separation to isolate and concentrate the glass shards for analysis. Treatment with acids and ashing to separate tephras can cause significant chemical modification and even crystallisation of the glass and should be avoided if possible.

Potential users are strongly encouraged to discuss the sample preparation with TAU Staff prior to arrival. Grinding, polishing and carbon coating facilities are available within the Tephra Analysis Unit.