What can we really learn from the chemical composition of the metasediments of the Tatricum of the Western Carpathians? Tribute to Stefan Meres

The purpose of this contribution is to present a geochemical study of the Tatric crystallinic of the Western Carpathians (WC) based on the evaluation of the chemical composition of metasediments. Structural, lithological, metamorphic and age data from the Tatric crystallinic of the Western Carpathians show that the pre-Mesozoic Tatric plinth consists of two different rock complexes, referred to as the lower stage (having an older age and an overall more metamorphic character) and the upper stage (younger in age with low step metamorphosis). The chemical composition of the meta-sedimentary rocks of the WC Tatric shows that they are metamorphosed clastic (clastics, arkoses, sandstones) and clayey (siltstones, claystones) rocks forming flyschoid sequences. The alteration/weathering indices (CIA, PIA) of the studied rocks indicate a low to moderate degree of damage to the original source rocks, while the increased values in the upper layer may be a consequence of recycling. The composition of the studied metasediments shows that their protolith was intermediate to acidic magmatic/volcanic rocks. Geochemical data point to the origin of the sediments of both stages of crystalline Tatric metamorphism WC in the environment of the Passive margin = PM, as well as the Active continental margin = ACM, which is actually a continental arc of the Andean type. The marked MDA and DA age differences in the rocks of both stages document that they were sedimented in different basins, such as the Rheic Ocean and the Rheno-Hercynian Basin. Their current position and convergence is a consequence of subduction/collision processes at the end of the Variscan orogeny. (authors)