What Is Diatom-Based Biostratigraphy?

Diatoms are considered as one of the critical biostratigraphic tools, especially where calcareous fossils are absent or poorly preserved. While diatoms were common both in marine and non-marine paleoenvironment, diatom-based biostratigraphy is widely used in the marine stratigraphic record. Multiple Deep Sea Drilling Projects (DSDPs) made the core samples available from Antarctic, Equatorial Pacific, and High Latitude North Pacific region. The earliest known fossil diatoms are from Lower Cretaceous in age, although fossil record is limited. Diatoms might have a much longer history, but because of their mineral instability under lithostatic pressure, well-preserved diatoms become rarer with older rock strata (Harwood and Nikolaev, 1995). Globally Cenozoic marine successions are rich in diatoms, and its biostratigraphy is based on regional and global first and last occurrence of unique, short-lived diatom with widespread …show more content…
Though, the diatom species have a long stratigraphic record from upper Cretaceous to Holocene, many short ranging species with few million years or less serve as a well-developed biohorizon with ages calibrated to the radiometrically dated geomagnetic timescale. The combination of multiple tools including diatoms results in age control of million years to as little as hundred-thousand-year resolution. Although rapid mass extinction of marine diatoms during that time is rare, multiple sharp evolutionary turnovers during Cenozoic were identified (Figure 4) and are correlated with global benthic foraminiferal oxygen isotope curve (Scherer et al., 2007). The rapid evolution of marine diatoms during Cenozoic time coincided with major climatic cooling period at high latitude or major reorganization of ocean’s surface water circulation (Scherer et al.,