Palaeontology in a broad sense is the study of the remains or traces of the activities of once living organisms called fossils which have been stored in rocks through natural processes. Palaeontology can generally be sub-divided into;
Modes of fossil preservation
Fossils are preserved either as unaltered body fossils or altered fragments and traces through one or a combination of the following processes.
Microfossils Used in Petroleum Exploration
Three main groups of microfossils have been extensively used in petroleum exploration. They include foraminifera, Calcarous nannofossils and palynomorphs.
Foraminifera: These are protists that form shells called tests by secreting calcium carbonate or gluing sand and salt grains together. They first occuured in benthonic and evolved later (Mesozoic and Cenozoic) to planktonic forms.
Calcareous Nannofossils: they are extremely small (usually <25µm) organisms made up of calcium carbonate and are mostly produced by marine algae.
Coccolithophorans are known for the production of plantonic golden brown algae nannofossils. The organism produces calcareous plates (coccoliths) as shells which they shed after growth or death. The shells accumulate to form the nannofossils
Palynomorphs: these are organic walled microfossils consisting mainly of plant pollen and spores as well as some marine organisms like dinoflagellates. They are generally very resistant to weathering and transportation, hence are transported over very long distances and are amongst the most abundant fossils.
August 18, 2021
August 19, 2021