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The contact coring technique freezes a surface disc of sediment (2-3 mm deep) with a diameter of 56 mm (Honeywill et al., submitted). The equipment needed for this procedure is; aluminium dish, plastic collar, liquid Nitrogen (LN2), slicer (artists palette knife), labelled aluminium foil.
- Set aluminium dishes, with the plastic collar in place, onto the sediment surface and gently pushed down to the depth of the collar (2mm), so the base of the dish makes contact with the sediment surface.
- Pour liquid nitrogen (LN2) into the dish.
- After 30 seconds remove the dish with collar still attached. Freezing times need to be assessed for each site, as water content and ambient temperature affect the time need to freeze 2mm of sediment, typically times range between 10 and 30 seconds.
- Quickly remove any sediment not flush with the collar by scraping the artists palette knife across the base of the corer, level with the edge of the plastic collar.
- Remove collar and push out frozen disc of sediment and wrap in a piece of pre-labelled foil and place under LN2.
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