Reworking of plant microfossils and sedimentary provenance

Reworked plant microfossils are commonly recovered from sediments along with palynomorphs regarded as in situ. Their potential for locating the source of terrigenous clastics is perhaps generally underestimated. Recognition of reworking may depend on taxonomic identification or differences in colour and preservation, and sometimes on variations in response to staining and fluorescence microscopy. This is demonstrable in some Mesozoic and Cenozoic sequences in NW Europe, with mixed assemblages suggesting derivation from deposits of more than one age and/or source area and geothermal history. Reworked palynomorphs can also indicate the presence of rocks or sediments in the vicinity of a site of deposition that have now been completely removed by erosion.