08-09-2017, 12:11 PM
Diagenesis is the change of sediments or sedimentary rocks existing in a different sedimentary rock during and after the formation of rocks (lithification), at temperatures and pressures lower than that required for the formation of metamorphic rocks. Does not include weathering changes. It is any chemical, physical or biological change suffered by a sediment after its initial deposition, after its lithification. This process excludes surface alteration (weathering) and metamorphism. These changes occur at relatively low temperatures and pressures and result in changes in the original mineralogy and texture of the rock. There is no defined boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwaters, porosity, permeability, solubility and time are influential factors.
After deposition, the sediments are compacted, as they are buried under successive layers of sediments and cemented by minerals precipitating from the solution. Sediment grains, rock fragments and fossils can be replaced by other minerals during diagenesis. Porosity generally decreases during diagenesis, except in rare cases such as the dissolution of minerals and dolomitization.
The study of the diagenesis in the rocks is used to understand the geological history that they have undergone and the nature and type of fluids that have circulated through them. From a commercial point of view, these studies help to evaluate the likelihood of finding several economically viable hydrocarbon and mineral deposits. The process of diagenesis is also important in the decomposition of bone tissue.
After deposition, the sediments are compacted, as they are buried under successive layers of sediments and cemented by minerals precipitating from the solution. Sediment grains, rock fragments and fossils can be replaced by other minerals during diagenesis. Porosity generally decreases during diagenesis, except in rare cases such as the dissolution of minerals and dolomitization.
The study of the diagenesis in the rocks is used to understand the geological history that they have undergone and the nature and type of fluids that have circulated through them. From a commercial point of view, these studies help to evaluate the likelihood of finding several economically viable hydrocarbon and mineral deposits. The process of diagenesis is also important in the decomposition of bone tissue.