The Corona Formation is a geologic formation of the Carnian Alps at the border of Austria and Italy. It preserves fossils dated to the Gzhelian stage of the Late Carboniferous period.
The thick formation comprises deposited in a deltaic environment. The Corona Formation has provided fossils of fish, brachiopods, a bryozoan, an insect, fossil flora including trunks and ichnofossils ascribed to Limnopus. The tracks from the Corona Formation include the oldest record of tetrapod tracks from the Southern Alps. The rugose coral Amplexus coronae was named after the formation.
Description
The Corona Formation was defined as a formation by Venturini in 1990. It is the lowermost Gzhelian unit in the late Pennsylvanian Pramollo Group, overlying the Kasimovian Pizzul Formation and overlain by the Auernig Formation in the Carnian Alpine border region of Austria and Italy. The mountains Monte Auernig, Monte Carnizza and the eponymous Monte Corona are composed of the formation. The formation is a thick succession, characterized by alternating quartz conglomerates, sandstones and mudstones. The conglomerates are coarse infillings of distributary channels in a deltaic environment. The formation is characterized by cyclothems (parasequences) of thick.
Fossil content
The Corona Formation has provided fossils of: Fish Petalodontiformes Petalodontidae Petalodus ohioensis Insects Palaeodictyoptera Dictyoneuridae Arltia carnica Rugose corals Zaphrentis omaliusi Lopholasma carbonaria Amplexus coronae Strophomenata Productida Rugosochonetidae Capillomesolobus pontebbanus Paramesolobus sp. Bryozoa Rhombocladia delicata Foraminifera Badyina lucida Hemidiscus sp. Ichnofossils Limnopus
The tracks of Limnopus from the Corona Formation represent the oldest record of tetrapod tracks from the Southern Alps.
Flora
The formation has also provided abundant, well-preserved and diverse plant assemblages in coal-rich levels of up to in the fine sandstones and shaly levels of the Corona Formation. Therein, sphenophyte trunks with a diameter of up to are preserved in situ. The genus Lebachia, typically known from the Permian, is not found in other Carboniferous strata in the Alps. The flora is of importance as one of the earliest examples of rebound after the Carboniferous rainforest collapse.
Acitheca polymorpha
Annularia carinata
Anthracoporella sp. Calamites carinatus Lepidodendron cf. subdichotum Linopteris neuropteroides Neuropteris cordata Paripteris cf. linguaefolia Pseudomariopteris busquetii Alethopteris sp. Pecopteris sp. Polymorphopteris sp.
See also
List of fossiliferous stratigraphic units in Austria
List of fossiliferous stratigraphic units in Italy
Bajo de Véliz Formation, contemporaneous fossil flora-bearing formation of Argentina Ganigobis Formation, contemporaneous fossil fish-bearing formation of Namibia