Information AboutBiostratigraphy |
| CATEGORIES ABOUT BIOSTRATIGRAPHY | |
| paleontology | |
| stratigraphy | |
| fossils | |
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Ammonite s, Graptolite s and Trilobite s are Index Fossil s that are widely used in biostratigraphy. Microfossils such as Acritarchs , Chitinozoa ns, Conodonts Dinoflagellate cysts, Pollen , Spores and Foraminifera ns are also frequently used. Different fossils work well for sediments of different ages; Trilobite s, for example, are particularly useful for sediments of Cambrian age. To work well, the fossils used must be widespread geographically, so that they can occur in many different places. They must also be short lived as a species, so that the period of time during which they could be incorporated in the sediment is relatively narrow. The longer lived the species, the less accurate the correlation, and so fossils that evolve rapidly, such as ammonites, are favoured over forms that evolve much more slowly, like Nautiloid s. |
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