Kőzetdeformáció mechanikai és geokémiai folyamatok határán üledékes medencékben

Rock deformation at the interaction of mechanical and geochemical processes in sedimentary basins

Abstract

Attesting deformation, natural fractures and faults are pervasive in low-porosity rocks in sedimentary basins. In the diagenetic realm fractures in rocks locally affect the flow of hot, reactive fluids and rock strength. Hot fluids cause dissolution, cement precipitation, and other chemical reactions, which can profoundly modify where fracture porosity, and as a consequence, connectivity exists. Although fractures may form in different settings at different locations, and at different times throughout a basin evolution history, they can potentially show similar patterns and geometric attributes, such as their position relative to bedding, shapes, aperture sizes, and cement infill types and textures. The similarity of patterns and geometric shapes impedes interpretation of intrinsically limited subsurface fracture data. Cement infills and textures, fluid inclusions trapped within, and cement isotopic compositions, on the other hand, can provide powerful evidence useful for unraveling the origin and timing of fracture formation. This presentation offers a glimpse into how geochemical analysis of fracture cements is revolutionizing fracture description and interpretation, and shows how the complexity of cement deposits are the key to unlocking the otherwise difficult-to-interpret simple patterns and geometric shapes of opening-mode fractures.