Chemical composition of allochthonous melt- rocks possibly associated with proposed Krk impact structure in NW Croatia, comparison of three spectroscopic methods and recognition of source-rock lithology

Chemical composition of melt-rocks from several localities around proposed post-Eocene Krk impact structure in Croatian carbonate (a.k.a. External) Dinarides was analyzed by three spectroscopic methods to decipher their source lithology. The utilized spectroscopic methods were ICP-AES, TXRF and PIXE+EBS, and their applicability for the analysis of melt-rocks was tested. The three analytical techniques provided comparable elemental compositions of the analyzed samples, but PIXE+EBS proved the best as undestructive method with easier and faster sample preparation, and reliable and consistent results. The obtained results show high discrepancy in chemical composition of analyzed melt-rocks with published data on Eocene Adriatic flysch, but close affinity with Pleistocene Adriatic loess. Consequently, the parent material of melt-rocks was probably loess, which might indicate the approximate age of the melt formation as Pleistocene.