Description
Authentic Cardioceras cordatum Ammonite Fossil
This listing features a genuine Cardioceras cordatum ammonite fossil, originating from the Middle Oxfordian Stage of the Jurassic Period, discovered in the Ardennes region of France. Dating to approximately 161–159 million years ago, this specimen represents one of the most scientifically important ammonites of the Oxfordian, serving as a key biostratigraphic marker in Jurassic geology. The fossil shown in the photographs is the exact specimen you will receive, and it is accompanied by a Certificate of Authenticity, guaranteeing that it is a 100% genuine specimen.
Geological Context
The Middle Oxfordian Stage was a critical period within the Late Jurassic, during which ammonite faunas flourished across Europe’s shallow epicontinental seas. The Ardennes region of France is well known for its fossil-bearing strata, particularly rich in ammonite material. Sediments from this area record marine conditions ideal for the preservation of cephalopods, allowing fine details of the shells to fossilise. Fossils from this level not only provide insight into the marine life of the time but also serve as essential tools for correlating Jurassic rock layers across vast regions of Europe.
Scientific Classification
- Species: Cardioceras cordatum
- Genus: Cardioceras
- Family: Cardioceratidae
- Superfamily: Stephanoceratoidea
- Order: Ammonitida
- Class: Cephalopoda
- Age: Middle Oxfordian, Jurassic (~161–159 million years ago)
- Locality: Ardennes, France
Morphological Features
The Cardioceras cordatum ammonite is recognised for its robust, moderately involute shell with distinctive ribbing. The ribs extend strongly across the flanks, often bifurcating towards the venter, creating a striking and easily recognisable ornamentation. Its whorl section tends to be rounded to sub-oval, and the ribs give the shell a sculptured, dynamic appearance. These morphological features not only provide taxonomic clarity but also make the specimen visually impressive for collectors and display purposes.
The ribbing pattern and shell proportions are defining characteristics of C. cordatum, setting it apart from closely related members of the genus. Its distinctive morphology and widespread distribution make it an invaluable ammonite for identifying and dating Middle Oxfordian strata.
Stratigraphic and Palaeontological Importance
Cardioceras cordatum is one of the most significant index fossils for the Oxfordian Stage. Its presence defines the Cordatum Zone, one of the primary ammonite biozones used by geologists to establish the sequence of the Jurassic worldwide. The Cordatum Zone is particularly important for correlations across Europe, making specimens such as this one crucial in understanding Jurassic stratigraphy and palaeoecology.
This species not only reflects evolutionary developments within the Cardioceratidae family but also illustrates broader palaeobiogeographic patterns, as it is found widely across European localities. Its stratigraphic precision has made it one of the cornerstone ammonites for Jurassic studies.
Depositional Environment
During the Middle Oxfordian, the Ardennes region was part of a shallow marine environment within the Western European epicontinental sea. Fine marine sediments accumulated on the seafloor, preserving a diverse array of marine organisms, including ammonites, belemnites, bivalves, brachiopods, and marine reptiles. The burial of ammonites like Cardioceras cordatum in these sediments allowed for the exquisite preservation of their shells, which are now valuable palaeontological specimens.
Collector and Display Value
This Cardioceras cordatum ammonite fossil is not only a scientifically important specimen but also a highly attractive display piece. Its ribbed ornamentation and historical significance as the index fossil of the Cordatum Zone make it a prized acquisition for collectors, educators, and enthusiasts. Whether displayed as part of a private collection or used as an educational specimen, it offers a tangible link to the Jurassic seas of 160 million years ago.
Item Details
- Type: Fossil Ammonite – Cardioceras cordatum
- Age: Middle Oxfordian, Jurassic (~161–159 million years ago)
- Location: Ardennes, France
- Notable Features: Index fossil of the Cordatum Zone, strong ribbing, well-preserved details
- Scale: Rule squares/cube = 1 cm (see photographs for accurate sizing)
- Authenticity: 100% genuine specimen with Certificate of Authenticity
- Specimen: The actual fossil shown in the photos is the one you will receive
This superb specimen of Cardioceras cordatum from the Ardennes, France, captures the essence of Jurassic ammonites, combining scientific value with striking natural beauty.
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