Biostratigraphy Pronunciation

Fun Facts

• ✓William Smith, a British canal surveyor with no formal university education, figured out in the 1790s that specific fossil species always appeared in the same rock layers in the same order across England, laying the groundwork for all biostratigraphy before the word even existed.
• ✓Index fossils, the key tools of biostratigraphy, must meet four strict scientific criteria: the organism must have lived for a geologically short time, been abundant, been geographically widespread, and be easy to identify, which is why tiny ocean plankton called foraminifera are more useful than most dinosaur bones.
• ✓The Cretaceous-Paleogene boundary, the precise rock layer marking the mass extinction that wiped out non-avian dinosaurs 66 million years ago, was identified and pinpointed globally using biostratigraphic methods before radiometric dating confirmed the date.
• ✓Oil companies spend billions of dollars a year employing biostratigraphers to analyze microfossils in drill cores because knowing exactly which rock layer you are in tells you whether you are likely to find petroleum reserves beneath you.
• ✓The smallest index fossils used in biostratigraphy, called conodonts, are tooth-like structures from an ancient eel-like animal and are often less than 1 millimeter long, yet they allow geologists to date rocks to within a few hundred thousand years across 200 million years of Earth history.