Burial diagenesis of carbonate rocks

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Diagenesis comprises all mineralogical, physical, and chemical changes that happen to  sedimentary deposits from the time of deposition at the Earth's surface to burial at depths of about 6 - 9 km and commensurate temperatures of about 200 oC. While some diagenesis happens very close to the surface, most diagenesis occurs during burial. Certain diagenetic processes are typical for shallow (max. 1 km), intermediate (about 1 - 3 km), or deep (about 3 - 9 km) burial. Investigation of rocks from various burial depths can provide an understanding of diagenetic processes and their effects on the rocks. Such studies can be done on drill core and on outcrops of rocks that were formerly buried and then exhumed.    Most diagenetic processes are facilitated by the flow of groundwater that is contained in and passes through the pore spaces. Hence, porosity and permeability (a measure for the ease of pore water flow), flow rate and pore water salinity, are important controls on diagenesis. The main results of diagenesis are solidification of the loose sediments to rocks, and changes in mineralogy and texture, which can modify porosity and permeability dramatically. In extreme cases, a rock can have highly enhanced porosity and permeability due to extensive mineral dissolution, or it can be completely plugged up due to extensive mineral precipitation.Diagenesis is of supreme importance for human civilization. Because of the changes in porosity and permeability, diagenesis affects the ability of the rocks to carry or store groundwater (used for human consumption and irrigation in relatively shallow settings), oil and gas (commonly in deeper settings), and certain metal ores (shallow or deep settings). This research program deals with all types of diagenesis in carbonate rocks, which are either limestones (calcium carbonate) or dolostones (calcium-magnesium carbonate). It is an extension of earlier work and will focus on Devonian and Carboniferous rocks of western Canada. Rocks of similar age (more than 300 million years old) in Germany and Spain, as well as of younger age in Texas and the Caribbean, will also be studied for comparison.