New evidence for the origin of distinctive quartz overgrowth textures in the Raisby Formation (Zechstein carbonate), north-east England

Petrographic study of a dolomitic sandstone within the Upper Permian Raisby Formation in Northumberland has revealed distinctive quartz overgrowth textures on detrital sand grain surfaces. These textures, comprising discontinuous ridges of authigenic quartz in a regular pattern, have previously been interpreted to be the result of replacement of quartz by carbonate crystals. However, rare textural inter-relationships between dolomite and quartz in this sandstone demonstrate that the ridges result from the growth of authigenic quartz along narrow pore spaces between dolomite crystals. This process may have important consequences for the petrophysical characteristics of mixed carbonate - siliciclastic reservoir rocks. -Authors.King Saud Universit