About Natural History

Archive for the tag “Fossils”

The time-averaging thing…

The palaeontologists that taught classes in the university I attended (UPMC, Paris VI), always told us we should be cautious while studying any fossil assemblage because it is important to take “time-averaging”* into consideration. It is very important, they told us, and I thought that I had understood it (as did my classmates). This until last week when I found an article by Michal Kowalewski (1996) on the subject, and I found out that the theory of the matter is very complicated.
I am not going to discuss the details, but what I wanted to put forward is the concept and theoretical work that had to be done in order to establish the notion of time-averaging and how it works. It is indeed quite complicated and shows that it is necessary to work on what I’d call theoretical geology.


*time-averaging: the fossils contained in a single sedimentological layer haven’t died and fossilised synchronously. Also, the different organisms that are found fossilised, don’t have the same fossilisation potential. This can create various problems while studying the assemblages, and the studies that have been carried out concern all the aspects of this phenomenon.

Excavation day in Pikermi!

Last Monday, we went, with a small group of students accompanied by a professor, in Pikermi for a day of excavation.
Pikermi is known for the savana-type fossil faunas: rinoceros, giraffes, saber-tooths, pigs, hipparions, and other animals that do not live in european lands anymore.

Here are some pictures:

Pikermi stream

Here I am, I dug up – with a friend – an upper jaw of a hipparion with 4 molars attached. The stream – small river – made it a little harder to dig…

Bottom of the river


In this picture there is a whole cranium that took two or three hours to take out of  the sediment.

Although we worked only for a day, we found very nice specimens!


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