Saturday, July 25, 2015

Diagenetic Processes in Limestone

Limestones are strongly affected by diagenetic processes that accompany lithification. Aragonite will be replaced by calcite (if the original carbonate mineral was aragonite), dissolution may be significant , and calcite may be replaced with dolomite.

Limestone is often impure. Calcium carbonate may be mixed with siliclastic material (clay, sand) in all proportions but calcium carbonate must form the majority. Otherwise, we have calcareous sandstone or marl instead of limestone. The term 'marl' is mostly used in the field and often somewhat muddy limestones, even if they contain more calcium carbonate than mud, are called that way.

Reference: Jackson, J.A. (1997). Glossary of Geology. American Geological Institute. 

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