Late Neogene-Quaternary radiolarian biostratigraphy: a brief review
Abstract. Since the 1950s, it has become apparent that Radiolaria have significant biostratigraphical potential throughout Phanerozoic time, including the Late Neogene and Quaternary. Radiolarian biozonation schemes for this period have been developed, including a Standard Tropical Zonation, which illustrates the pan-oceanic application of radiolarian biostratigraphy to Pliocene–Quaternary sediments. The biostratigraphical resolution obtainable using Radiolaria is equivalent to other microfossil groups, such as planktonic foraminifera. The recognition of abundance events of Cycladophora davisiana, and of some other species, are an alternative radiolarian dating technique for the Pliocene–Quaternary, akin to dating sediment using oxygen stable isotope (δ18O) records and with similar resolution. A number of studies have used astronomical timescales, derived from orbitally tuning δ18O and gamma ray attenuation porosity evaluator (GRAPE) records, to provide ages for radiolarian biodatums. This approach should be adopted as a more accurate alternative to palaeomagnetic chronologies with their inherent flaws. This commentary concludes that Radiolaria are important microfossils and, as a group, continue to offer significant potential as a biostratigraphical tool in future studies of the marine Pliocene–Quaternary.