Upper Cretaceous lithostratigraphy of the Panagyurishte strip (Central Bulgaria) – part of the Late Cretaceous Apuseni-BanatTimok-Srednogorie magmatic belt

Abstract

The investigations of the Upper Cretaceous Panagyurishte and Chelopech volcano-sedimentary strips of the Central Srednogorie tectonic subzone date back to the end of 19th and became more intensive during the middle of the 20th century, mainly due to the discovery of important mineral deposits in the area. Our field work during the last 15 years and analysis of previously published data show that the existing lithostratigraphic scheme does not cover the entire spectrum of lithologies, successions and interrelations in both strips. This study deals with four stratigraphic sections, along the valleys of the Topolnitsa, Kamenitsa and Mirkovska rivers, and their correlation on the basis of the Turonian/Coniacian boundary, local extinction event and palaeontological data that demonstrate the unreliability of already existing schemes. The previously used “layer-cake” stratigraphic model does not reflect the diachronism of the studied units or the existence of subaerial volcano craters, together with synchronous deposits. In this paper, we also propose a subdivision of the intervals containing magmatic and sedimentary rocks into individual members, including non-layered magmatic centres, stratified lava flow and volcanoclastic flow deposits and stratified epiclastic deposits of mainly turbiditic origin, instead of the currently used Chelopech Formation. The presented herein new data do not cover entirely the wide palette of problems with the lithostratigraphy of the area, but clearly demonstrate the necessity of its revision, especially for practical application and better understanding of the Late Cretaceous evolution of the area.