For some analyses (e.g. micropaleontological, compositional,
etc.) it’s essential to freeze dry the sediment rather than oven-dry it.
Freeze-drying it’s preferable to oven drying because it
removes the water content without greatly altering the physical structure of
the sediment. As a result, sediments containing clay are much easier to handle
(they remain friable) and diatom or foraminifera breakage, resulting from
contraction of the sediment during drying, is greatly reduced. Furthermore, the
formation of carbonate aggregates on the surface of calcareous microfossils due
to carbonate re-precipitation, which may change their isotopic composition, is
also prevented.
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