The fossils in Percé
Hello science apprentices!
One of our apprentices asked me a very interesting question! Dominic wants to know: Are there other fossils, besides the trilobites, in Percé? Indeed, there are several! In Perce a large number of these fossils are found in geological formations consisting of limestone.
But why this type of rock?
"In the majority of cases, limestones are formed in part by the accumulation of calcareous shells and skeletons. Thus, limestone is a carbonate sedimentary rock containing at least 50% calcite (CaCO3). However, some of these rocks are formed by chemical or biochemical precipitation "(Foucault, A. and Raoult, J.-F., 2010, Dictionary of Geology (7e edition), France: DUNOD, pages: 380.).
Here is the summary description of some fossils found in our beautiful region. I found a large amount of this information in a very interesting document: Small Treaty of Urban Paleontology: Fossils in the Architectural Stones of Quebec City.
To learn more about the morphology of these fossils, I invite you to consult this document from the Ministry of Energy and Natural Resources. It will also make you discover how fossils can integrate into human constructions?
Source: Ministry of Energy and Natural Resources, 2017. Small treatise of palaeontology urban: fossils in the architectural stones of Quebec City.
1- It is my pleasure to introduce you to the beautiful crinoids ! Our dear Agathe loves them particularly. The oldest fossils found date back to about 480 million years, that is to say at the time of Ordovician (I put a geological calendar lower down to help you find yourself in all these millions of years?).
So far, scientists have identified more than 5000 fossil crinoid species. Complete fossils are rare. In the photo below, the small columns are stems whose center can have different shapes, depending on the species. Crinoids are still present today, we call them sea lilies. Nice!
2- The Bivalves are mollusks that appeared around 450 million yearsbut they still exist today and I bet you've already eaten it! Indeed, mussels, oysters and clams are Bivalves!
Very varied, the habitat of Bivalves can go from the littoral, to depths of 5 500 meters!
3-The Gastropods are molluscs of salt water and fresh water, according to the genera and the species. They appeared at Cambrian, there is more of 500 million years! They are still living today.
In fact, it is one of the best-represented invertebrate groups on earth, both in diversity and abundance.
4- The Brachiopods are invertebrates called microphage or filter. Since the Cambrian, there is 550 million yearsthey have diversified to more than 7000 known fossil species.
Today brachiopods only matter 260 species.
In conclusion: You have probably noticed that, unlike trilobites, these types of fossils (or taxonomic groups) are still present today. The planet has undergone several upheavals since the emergence of life on earth. Some life forms have managed to survive and adapt better than others to these changes. That is why the human being must remain attentive to the changes that our planet is currently experiencing!
See you soon !