The Use of Foraminifera and Ammonites in Biostratigraphic and Paleoenvironmental Interpretation of Marine Realms in the Cretaceous Period of Earth’s History

The use of Foraminifera and Ammonites in Biostratigraphic and Paleoenvironmental interpretation of marine realms in the Cretaceous period of Earth’s history


For many decades applied paleontology has concentrated on finding energy resources. However to determine if the right conditions were present to aid in the formation of organic rich shales oil companies have looked to micropaleontologist (Ventress, 1991, LeRoy, 1977). Micropaleontologist uses both micro and macro fossils in paleobiostratigraphy and Paleoenvironmental interpretations to date and correlate rock strata and interpret the environment in which they were deposited.
The Cretaceous period contained warm and humid conditions and was accompanied by a long-term sea-level rise (Haq et al., 1987; Fig.1.1), and elevated average temperatures (Barron et al., 1995). These specific palaeoceanographic conditions in the mid-Cretaceous favoured the deposition and burial of organic, carbon-rich sediments subsequently preserved as black shales (e.g., Schlanger and Jenkyns, 1976; Arthur and Premoli Silva, 1982).
Some fossil groups are excellent for biostratigraphy, while others are excellent for interpreting paleoenvironment. The micro fossil foraminifera have many uses to applied paleontology both in biostratigraphy and Paleoenvironmental interpretations of the Cretaceous period. The ammonite fossil due its morphological variations, short lifespan and extensive geographic occurrence has made it an excellent index fossil to date Cretaceous rocks and rock Strata. The disadvantage of one fossil is the advantage of another, therefore when used together micro and macro fossils can successfully be used to enhance the quality of reservoir potential assessment as well as migration modeling (Jenkins, 1993).


Paleontologist have successfully used foraminifera and ammonite fossil assemblages to interpret biostratigraphy and paleoenvironment during the late Mesozoic, Cretaceous period. The...