Rila-West Rhodopes Batholith and petrographical diversity of Rila Geopark

Abstract

The full retrospective of the petrographic study of the Rila granitoids, which are an essential part of the geodiversity of Rila Geopark, is crucial for the impartial assessment of its geoconservation value and for developing appropriate promotional materials in a language accessible to the general public. The Rila-West Rhodopes batholith, the largest batholith in the Balkans, contributes to the continental significance of Rila Geopark with its remarkable petrographic diversity of granitoid rocks and numerous pegmatite, aplite and quartz veins, vein-like granite and diorite bodies favorable for demonstrations of the principle of cross-cutting relationships in geology and illustrating the crystallization processes in igneous rocks as well as magmatic structures and textures. Due to their extremely wide distribution in Rila, the granitoids of the Rila-West Rhodopes batholith crop out along the routes of all previously described geotrails and are native rocks for most glacial forms that define the concept of Rila Geopark. From this point of view, a full review of the geological study of the batholith is a necessary condition for any subsequent step in the geopark development and its nomination for the UNESCO Geopark. This article offers a brief but comprehensive historical overview of the current petrographic studies, which will serve as a basis for the development of information panels located along the described geotrails. Particular emphasis should be placed on the connection between petrology and local crafts in the past, which is contained in the very slogan of Rila Geopark “Land of Iron and Water”. It includes the memory of the primitive crafts associated with the extraction and forging of iron in the Middle Ages, and water in its three states – ice (the glacial history of the mountain), steam (geysers and geothermal springs) and liquid phase – the source of the longest rivers in the Balkans.