Lithologic controls on morphology of pressure dissolution surfaces in Paleozoic carbonates from the mideastern U. S

Quantitative examination of pressure dissolution surfaces (stylolites and dissolution seams) in carbonate rocks from the mideastern US demonstrates that morphology of these surfaces is dependent on rock fabric. Morphology of these pressure dissolution surfaces can be effectively quantified using just four parameters: thickness (T) of the surface, amplitude of irregularity (I) of the surface, amplitude of vertical offsets (O) of the surface, and frequency (F) of offsets along the surface. I and O vary with T, reflecting the progressive development of stylolites, whereas F varies with 1/T, apparently because the physical strength of a stylolite inhibits formation of offsets. Mean values of F, O and T are greater in grainstones and packstones than in mudstones and wackestones, and mean values of T and O are greater in limestones than in dolostones. The proportion of dissolution seams to stylolites decreases through the lithologic spectrum from mudstones to grainstones. These relationships suggest that elaboration of pressure dissolution surfaces depends on the heterogeneity of the carbonate fabric. Maximum values of T and O in grainstones are correlative with abundance of intergranular cement. Within those grainstones, grains disproportionately occur as leading or penetrating elements of stylolite columns, and by contrast cements are apparently disfavoredmore » to survive stylolite development. Dissolution seams occur only in rocks containing fine-grained dolomite, and in those seams T and I decrease with increasing dolomite abundance. This relationship, combined with the observations from grainstones, suggests that development of pressure-dissolution surfaces is inhibited by relative abundance of pressure-resistant components such as carbonate grains and dolomite.« less