In geology, carbonates are a class of sedimentary rocks compose primarily of carbonate minerals. Two major types are limestone, which is composed of calcite or aragonite (different crystalline forms of CaCO3) and dolostone, which is composed of the mineral dolomite (CaMg(CO3)2).
- Where does come from carbon present in the carbonate rocks?
- What are the causes of the beggining of carbonate sedimentation?
- What are the processes responsible for the formation of dolomite and dolostone?
The ideas based on the principles of uniformitarianism have not resolved these issues. This problem is due geology not yet provided an understanding of the process of planetary formation, the origin of natural hydrocarbons and the carbon cycle, from deep within the Earth to ocean-atmosphere-biosphere systems.
Cap carbonates occur after glacial periods, mainly in Neoproterozoic (Sturtian and Marinoan glacial events). Methane released from permafrost with excess in atmosphere could be incresead to form overlying carbonate sequences.