Published 1994 as part of Memoir 61
Copyright © 1994 The American Association of Petroleum Geologists.   All Rights Reserved,

Pressure seals in the Anadarko basin contain distinct diagenetic bands that play a significant role in the isolation of high-pressure domains. Both sand-rich and clay-rich clastic rocks exhibit banding patterns. Banding in sandstones results primarily from the processes of pressure solution, pore-fluid interaction, and precipitation. Some banding patterns in clay-rich rocks appear to form independently of sedimentary textures while others result from the enhancement or modification of sedimentary features. All of these bands are noticeably absent in rocks that were never buried deeply enough to be overpressured. 

Diagenetic bands in sandstones consist of silica- and carbonate-cemented layers that are separated by clay-coated porous layers. Stylolites and other pressure-solution features such as penetrating grain boundaries suggest a mechanism for the derivation of silica cements. 

Diagenetic bands in clay-rich rocks appear to have two distinctly different origins. In the Pink/Red Fork interval, diagenetic chlorite bands exhibit no apparent relationship to sedimentary features. The chlorite bands have less porosity and smaller pore-aperture radii than the surrounding shale (Powers, 1991). In the Woodford Shale, silica- and clay-rich bands develop via the diagenetic modification or enhancement of sedimentary features.