The master's thesis presents the neptunian dykes from the Upper Triassic Dachstein limestone. The studied area is located in the northwern Slovenia, in a saddle between Batognica and Mt. Krn and along the way to the Gomišček shelter. This area is structurally part of the Southern Alps, specifically the Krn Nappe. Mesozoic rocks of the Southern Alps formed at the passive continental margin of the Tethis Ocean. During this period the margin experienced extension, which is a favourable condition for the formation of neptunian dykes. These are defined as bodies of younger sediment filling fissures in rocks exposed on the sea floor.
Based on the geometry of the neptunian dykes, they were classified into two groups: neptunian dykes with jigsaw structure and chaotic breccias. The geometry of the both groups is due to brittle deformation of the host rock. The corrosion voids appeared in the Dachstein limestone, which were formed after sedimentation of the limestone and before formation of the neptunian dykes.
A detailed microscopic research of the sediment that fills the corrosion voids and the neptunian dykes helped in determination of the relative timing of the fillings. The first step is represented by karstification of the host rock. The voids were then filled with allochthonous sediment transported by gravity flows or water currents, and partly with calcite cement. According to our research, the active extension, which caused the formation of the extensional cracks, started at the end of Jurassic or later. The open cracks were filled with breccia, which is composed of sharp clasts in red matrix, which may contain calpionellids. We could not confirm the older phases of opening and extension observed in the previous studies.
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