At the end of February and the beginning of March 2000, Cuc Phuong National Park collaborated with the Hanoi Geological Museum to conduct field research on vertebrate fossils found in limestone cliffs within Cuc Phuong National Park.
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Fossil impressions in layered limestone |
The fossil was exposed on the thin gray limestone cliff belonging to the Dong Giao Formation, dating back to the Middle Triassic period (T2). The visible portion of the fossil consists of a vertebral column measuring 70 cm in length, made up of 18 vertebrae, 12 of which are intact. The vertebrae are cylindrical with a constricted middle, concave surfaces, measuring 3.5-4 cm in length, with a diameter of 2.0-2.5 cm at the body center; the diameter at the center of each vertebra is 2.0-2.2 cm. Along with the vertebrae, two short clavicles were also found. An unclear structure resembling “fin bones,” four sharp ribs approximately 4 cm long, and several similar bones were also sporadically observed on the rock. Examination of some fragments revealed clear bone structures.
Along the route leading to the fossil site, geologists also observed sedimentary features and structures in the limestone, as well as signs of morphology and plant remains.
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Distribution diagram of fossils on the surface of the limestone layer |
Based on these observations, the geologists made the following initial assessments:
1. This is a genuine fossil of a marine vertebrate buried in Middle Triassic marine sediments, approximately 200-230 million years ago. Based on the morphology of the vertebrae, it is not immediately clear whether this fossil belongs to a fish or a fish-like reptile. The vertebrae exhibit characteristics of fish, while the clavicles and ribs show reptilian features.
2. Nevertheless, regardless of whether it is a fish or a reptile, this remains the first discovery of vertebrate fossils in Triassic sediments in Vietnam. This finding lays the groundwork for further research and the continued discovery of vertebrate fossils in these formations across other regions of our country. The presence of fossils and distinct geological features in the Dong Giao limestone will enhance the research and tourism value of the national park when designing study and tour routes.
3. For all the reasons stated above, geologists need to protect the fossil’s original state at the site, conduct detailed research on the existing fossils, organize further research, and search for fossils in the Dong Giao limestone within Cuc Phuong National Park, as well as preserve and curate the fossils according to outdoor museum standards.
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Fossil within limestone |
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