The Relationship Between Tectonic Stylolites and Fold Morphology in Limestones of the "Croatica Deposits" (Croatia)

Abstract

Stylolites associated with axial plane fractures occur in Lower Pannonian clayey limestones (the "Croatica Deposits") from the "Hampovica 6" deep exploration well. A genetic link has been observed between the origin of fractures and the process of stylolitization. Strong tectonic deformations are present which have been formed under the influence of reverse bed faulting. Deformation is pronounced in the shape of folded marl layers along with the creation of thick cleavage (0.3-0.5 cm). Along the fractures of axial plane cleavage, microlithons are separated and moved apart for similar values (2-5 mm) forming a moderate synform. Stylolites are formed in the last phase of structure shaping when the effects of the local compressional stress have weakened under the influence of which the breaking off and folding of marl layers occurred. Their strike cut the bedding and older fracture systems.