dissolution of framework silicate grains and previously formed carbonate cement may occur during deep burial. conditions that encourage this are essentially opposite of those required for cementation. rock fragments and silicate minerals of low stability, such as plagioclase feldspar, pyroxenes, and amphiboles, may dissolve as a result of increasing burial temperatures and the presence of organic acids in pore waters. the dissolution of frame work grains and cements increases porosity particularly in sandstones.