Secondary porosity (Selley, 1976) encompasses intercrystalline porosity, fenestral porosity, moldic porosity, vuggy porosity, and fractured porosity. Types of porosity commonly occur in sandstone are intercrystalline and fractured porosity. The other three types of porosity are typically found in carbonate rocks. Intercrystalline porosity occurs between crystals precipitated in diagenesis. On the other hand, fractured porosity is related to post-sedimentary structures and tectonics. Post-sedimentary structures are able to produce sedimentary faults and folds. A distinct example of fractured porosity due to tectonics occurs in anticline. Outer arc of a fold bears extension, generating tensional fractures and faults. Inner arc of a fold experiences compression, producing compressive fractures. | Secondary porosity (Selley, 1976) encompasses intercrystalline porosity, fenestral porosity, moldic porosity, vuggy porosity, and fractured porosity. Types of porosity commonly occur in sandstone are intercrystalline and fractured porosity. The other three types of porosity are typically found in carbonate rocks. Intercrystalline porosity occurs between crystals precipitated in diagenesis. On the other hand, fractured porosity is related to post-sedimentary structures and tectonics. Post-sedimentary structures are able to produce sedimentary faults and folds. A distinct example of fractured porosity due to tectonics occurs in anticline. Outer arc of a fold bears extension, generating tensional fractures and faults. Inner arc of a fold experiences compression, producing compressive fractures. |