Sara Biolchi, Stefano Devoto, Stefano Furlani, Igor Belamarić, Franco Cucchi, Radoslav Dodig, Goran Glamuzina, Jernej Jež, Bogdan Jurkovšek, Tea Kolar-Jurkovšek, Karmen Peternelj, Fabiana Pieri, Luca Zini, Gordana Zwicker Kompar, Irina Žeger Pleše
In the project area in Herzegovina three sites were selected for protection as geosites: Raška gora, Kolojanj, and the Grabova draga sites (for a more detailed description, see Appendix 2.4).
The proposed geosite Raška gora is located along the local gravel road near the village of Sirge. With a geological profile some 700 m long it lies entirely within the cadastral area of the road and does not occupy any private land at all. The proposed area is located just 1 km south of the high potential outcrops of platy limestones (Raška gora platy limestones).
The site is relatively easily accessible and can be reached from the City of Mostar, following the narrow solid asphalt road towards Raška gora. The largest part of the Raška gora karst plateau is located at altitudes of between 550 and 700 m a.s.l.
Within the idyllic forest landscape, the numerous karst features (including sinkholes and caves) lend exceptional natural and geomorphological value to this area. The spatial position of this area alone is another important reason for its protection as a natural heritage site. On the western side of the area Čabulja Mountain (1776 m) rises steeply, affording a breathtaking view of the highest mountains of Bosnia and Herzegovina – Čvrsnica (2225 m) and Prenj (2108 m) – towards the north. The canyons of both the Neretva and Bijela rivers are carved through the central mountain ranges and are as beautiful as they are impressive (Fig. 4.26).
The greatest value of the limestone at this site is its special paleontological characteristics, especially the fossil assemblages. These sediments are almost pure (99% of CaCO3) white limestone, and highly recrystallized in places. As a result they are often called “marbles” locally. Rudists (Fig. 4.27) are the most dominant fossil form found within the rocks along the section proposed for protection as a geosite.
In the southern part of the Bosnia and Herzegovina project area lies Kolojanj, a highly valuable geo-paleontological site with platy limestone of Upper Cretaceous to Lower Paleogene age. These platy limestone horizons contain well-preserved fish fossils, terrestrial macroflora and rudist bivalves. Preliminary paleontological observations have indicated that the most widely preserved fish specimen from this site could belong to the genus Scombroclupea (Fig. 4.28a).
In addition, some well-preserved, very attractive and rare rudist fauna (Fig. 4.28b) occur in these bioclastic limestones.
As additional value of the site, it is important to point out that one of the largest prehistoric hillforts (so-called ‘Gradina’) in Bosnia and Herzegovina and the wider region, with massive stone megalithic walls lies in the immediate vicinity of the proposed natural heritage site. As a result, alongside its important paleontological content are also highly valuable archaeological remains.
The last proposed geosite in the project area in Bosnia and Herzegovina is a small area along the southern side of a narrow valley in the eastern part of the village of Grabova draga. It is important owing to its outstanding paleontological, sedimentological and tectonic characteristics. In the northern part of the site, in fact, the Upper Cretaceous limestones and Paleocene sediments are in unconformable contact. Furthermore, newly-discovered Eocene platy limestone, similar to that found at the Raška Gora site, are exposed in the southern wing of an overturned syncline. Close to the core of the syncline we find a highly attractive and exceptionally large oyster Pycnodonta gigantica.
Among the fossils present here are terebratulid brachiopods, decapod crab Harpactoxanthopsis quadrilobata, bivalves Cardium, Pecten, Chlamys, and other diverse forms of gastropods and bivalves, as well as terrestrial flora and giant nautiloid cephalopods.
