As a crucial segment of the geological structure of the Western Carpathians, the Meliata Superunit represents a remnant of the closure of the Meliata Ocean. Its composition is defined by the blueschist facies Bôrka Nappe, a low-grade Jurassic sedimentary complex with olistostromes that constitutes the Meliata Unit sensu stricto, and a polygenous mélange including blocks of both unmetamorphosed and metamorphosed rocks. This study focused on the origin and processes associated with development of the Meliata Superunit, specifically examining the fine-grained marine sediments that form the matrix of the polygenous mélange. Our results from the Honce and Dobšiná localities indicate that the matrix of the polygenous mélange can be differentiated into two groups that are similar in lithology, but differ in their metamorphic overprint. The first group consists of unmetamorphosed or low-grade shales containing Upper Jurassic radiolarians. The second group is composed of phyllites, which exhibit a medium- to high-grade mineral assemblage, together with phantoms of radiolarians. A common sign of both groups is the presence of euhedral monazites, which were dated by electron probe microanalysis U–Th–Pb methods to an Early Cretaceous age of 150–95 Ma. We conclude that the sedimentation of the studied marine sediments occurred during the Jurassic and that these sediments were partially involved in the subduction process. Subsequent exhumation and the formation of an accretionary wedge led to their mixing with unmetamorphosed deposits during the Early Cretaceous, followed by reworking into a mélange. This mixing was accompanied by the incorporation of lithologically variable blocks of older, more resistant rocks and is recorded by the growth of post-kinematic monazite porphyroblasts.

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.