Name: Santana Formation
Lower Cretaceous, 108-92Ma
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Example of a concretion surrounding an ostracod

The term Konservat-Lagerstätte, is used to describe sites of palaeontological interest in which fossils have been exceptionally well preserved, usually with 'soft-parts' as well as 'hard-parts' present. The Santana Formation is one of these sites, and features not only articulated remains, but shows three-dimensionality in many specimens, especially insects.

Taphonomy is a study of what influences interact with the animal or plant after death. The rate of chemical breakdown of a dead organism is largely controlled by chemical, physical and biological processes occurring in the sediment or medium (e.g. amber) in which the dead organism is engulfed after death. The original molecular components of the organism should also be considered when studying diagenetic processes.

Many fossils from the Santana Formation have been found encased in limestone concretions. These structures would have slowly formed around the carcass subsequently providing a form of protection and thus aiding preservation (see picture above). In addition, early phosphate mineral replacement (phosphatisation) of soft tissues during decay, is also cited as an important preservational aid. Incredibly, some of the 'soft parts' preserved within the Santana Formation have included muscles, blood vessels, gill filaments, ovaries and ova, skin, and even stomach and intestinal linings (Martill, 1993).

Return to Santana Formation Fossils index page

Section author: Sally Haseman
Last updated: 20/11/02