This site contains the record of an important fluvial-lacustrine-swampy environment which existed here ca. 38-28 millions years ago (late Eocene – Early Oligocene).
Under a hot and humid climate, an incredible rich and diverse flora and fauna was living there. Mammals, crocodiles, fish, molluescs, plants, etc. were the inhabitants of this alternating river-lake-and-swamp environment. In terms of scientific importance, the river-lake and swamp sedimentation generated deposits which were, through time, transformed in rocks . Many rock layers can be observed and some of them are with different colors resulted from various erosion and sedimentation process. Inside these colored layers, a specific dark layer which corresponds to a rock called “lignite” can be observed. The name “lignite” comes from the Latin word “lignum”, which means "wood." Because the lignite was made from plants with a lot of resin, it has a lot of volatile stuff. Lignite contains about 60 to 70 percent carbon and has a great calorific value.
Mussel fossils
In this site of Non nuoc Cao Bang UGGp, life of this past fluvial-lacustrine-swampy environment is fossilized. Scientists didn't find there big animals -mammals or crocodiles- as they found in the south (Lang Son Aspiring Geopark) but they discover various interesting smallest fossils witness of this ancient fluvial-lacustrine-swampy biodiversity. The fossils present, here, are mainly composed of plants (transformed in lignite) and several fresh-water molluscs such as gastropods, mussels, etc..
Cao Bang Geopark
