Intrastratal Solution
Introduction
The selective dissolution of less stable framework grains or parts of grains during diagenesis is called intrastratal solution. [1]
Mechanism and Conditions
Dissolution of framework silicate grains and previously formed carbonate cements can occur during deep burial under conditions that are essentially the opposite of those required for cementation. Carbonate minerals are dissolved in cooler pore waters with high carbon dioxide partial pressures. Rock fragments and low-stability silicate minerals - including plagioclase feldspars, pyroxenes, and amphiboles - may dissolve as a result of increasing burial temperatures and the presence of organic acids in pore waters. [1]
Secondary Porosity
Dissolution of framework grains and cements increases porosity, particularly in sandstones. Petroleum geologists now believe that much of the porosity in sandstones below a burial depth of about 3 km is secondary porosity created by dissolution processes. [1]
Related Topics
Silicate Minerals: Structure and Classification
Silicate minerals are by far the most abundant group of minerals in the Earth's crust, and their diversity and economic importance make them the dominant focus of systematic mineralogy. The common...
Cementation (Diagenesis)
Cementation refers to the precipitation of minerals into the pore space of sediment, reducing porosity and bringing about lithification. Carbonate and silica cements are most common, but clay...
Carbonate Minerals
Carbonate minerals are the rock-forming constituents of limestones and dolomites. The principal carbonate minerals fall into three crystallographic groups — the calcite group (rhombohedral), the...
References & Citations
- 1.Principles of Sedimentology and Stratigraphy Boggs, Sam Jr.
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