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Coral hunting in the Weißenegg-formation, Styria, Austria (Langhian/Badenian, Miocene) – 10/17/2019
FranzBernhard posted a topic in Fossil Hunting Trips
Hello! Finally, I have some time to post this fossil hunting trip from a warm and sunny day in October, 2019. Introduction The Miocene Styrian basin in Austria is mostly filled with various clastic sediments, e.g. fossil-rich “Florianer Schichten” around St. Josef. The “Mittelsteirische Schwelle”, a north-south trending high-zone of palaeozoic, slightly metamorphic rocks, however, is, in a very literal sense, the base of various biogenic carbonate rocks (“Leithakalk”). The individual carbonate bodies are of slightly different age – spanning the whole Badenian (about three Million years) - and composition. The younger ones to the north around Wildon are characterized by coralline algae and often oncoidic limestones, corals are extremely rare there. To the south, corals became locally an important part of the limestones, besides the coralline algae. No really big coral reef structures have developed, though; coral carpets and small coral batch reefs are characteristic. Various maps from the internet and literature of the visited area. 1 = Kittenberg; 2 = Hötzlweg Depositional scheme of the Weißenegg-formation around the “Mittelsteirische Schwelle”. Within the green rectangle the area of interest. Relief map of the area north of Heimschuh. Note the many very small to medium-sized quarries. Some cliffs are also visible. These corals are witness of tropical to subtropical temperatures in this area about 15 Million years ago. Coral development is considered to depend on local factors like sediment input or (non-)exposure to severe wave action during storms. Coral diversity is relatively high, with at least a dozen of genera described or mentioned. About four years ago, I have prospected the area north of Heimschuh several times for corals. My goal was to find some good coral sites. Fossils in the wild are not super-abundant in this formation, but I succeeded to find a few good spots. Corals are by far the most abundant fossil group, bivalves etc. are much rarer. (Note: there is a very large, active quarry for portland cement fabrication in Retznei nearby, that is famous for all kind of marine stuff, incl. Meg teeth and other large vertebrates.) I will present two sites that I have visited again at 10/17/2019, but already also four years ago. One is at Kittenberg in the woods (1), the other one is a small outcrop along a minor road called “Hötzlweg” (2). Continued... -
Coral-ID - Weißenegg-formation, Styrian basin, Eastern Alps (Langhian, Miocene)
FranzBernhard posted a topic in Fossil ID
Waiting for Christkind and(!)/or(??) Santa Claus gives me some time putting together this question: The coral in question comes from the Styrian basin (Weißenegg-formation) and is Langhian/Miocene in age (ca. 15 Ma old). It comes from a very small road outcrop, mainly limestones, north of Heimschuh in the Sausal mountains, southern Styria, Austria. Beside massive, sturdy coral colonies like Montastrea, possibly Favites, etc., another colonial coral occurs in this outcrop, that disintegrates easily into individual sticks or pencils, aka corallites: Outcrop situation, field of view ca. 80 cm. It looks really something strange and unusual. These are individual corallites or they are in the stage of branching; the middle one is about 8 cm high. Sometimes you can retrieve parts of colonies. Remarkable is the large diameter of the corallites, up to 2 cm. With the help of some superglue, it was possible to make some polished slabs of these corals (the matrix is a rather soft marl). Note the highly varying diameter of the corallites and the budding. Especially interesting is the specimen to the lower left. Here, some big (about 2 cm diameter!) polygonal corallites are tightly growing together. But I think, its the same as the other ones. A possible genus that comes to my mind is Acanthastrea. This idea is based on the shear size of the corallites. This genus is know from an outcrop a few km away and also from a similar formation of similar age about 100 km away (Mühlendorf, Burgenland, Austria), the species mentioned/described there is A. horrida. But my idea, that these could be also Acanthastrea could be totally wrong, of course... Thanks for your help and Merry Christmas! Franz Bernhard