Mechanical Separation of Microfossil Residues

Abstract

Separating microfossils from a non-fossiliferous component within residues can be a tedious, although necessary process. To aid in this the micropalaeontologist can employ a number of methods. Sieving (wet and dry), and centrifuging techniques are detailed in other sections (see sections 16 WASHING AND SIEVING TECHNIQUES USED IN MICROPALAEONTOLOGY and 17 CENTRIFUGE TECHNIQUES USED IN MICROPALAEONTOLOGY). Liquid separation and flotation procedures can also be used, and have been detailed in section 19 FLOTATION AND LIQUID SEPARATION TECHNIQUES. Liquid separation procedures are extremely successful with Recent foraminifera and ostracods with hollow or air filled shell cavities (i.e. the light fraction), or denser microfossils such as conodonts and infilled foraminifera which sink (i.e. the heavy fraction). Separating calcareous microfossils from other calcareous elements of the matrix, or within quartz rich sediments, without having to hand pick, can be difficult. The Franz Isodynamic magnetic separator provides one means of tackling this problem.