Tiny grains of pollen and spores scattered millions of years ago are aiding the Arabian American Oil Company (Aramco) in its continuous search for new deposits of petroleum. Company oil drillers bring up, embedded in rock cores and cuttings, pollen, spores, and other acid-insoluble fossils such as Hystrichosphaerids and dinoflagellates. These ossils, composed of a cellulose-like material, are highly resistant to biological and chemical decomposition. The rock fragments, recovered from a wide range of depths and locations in Aramco's concession area in Saudi Arabia, find their way to the Exploration Department laboratory specializing in the newest branch of micropaleontology—the science of palynology.
A technician extracts the fossils, about 50 millionths of a meter in size, by an intricate series of steps involving crushing, acid baths, mechanical shaking and repeated separations of residue in a centrifuge. The resulting specimens are then mounted on slides and photographed through a powerful microscope. After being carefully catalogued, the mounted and magnified fossils are ready to be turned over to trained palynologists for interpretation.
Microfossils studied under high magnification reveal characteristic sizes, shapes and ornamentation which place them into readily recognizable groups. Through experience and by comparing microfossils at hand with illustrative literature and typical examples from the company's collection, Aramco palynologists are able to establish the age of the sediments from which the specimens were taken.
Petroleum geologists are always on the lookout for evidence of ancient shorelines, the sites of most of the world's oil deposits. The palynologist compares recently extracted, acid-insoluble fossils with specimens associated with shallow marine and brackish water sediments where the hunt for oil has been successful. Then, by correlation, he can designate those areas that appear to be most favorable for concentrated
oil exploration.
