导致无机灰岩形成的机制是岩浆碳酸盐岩岩石的风化作用。我发现Siilinjärvi碳酸岩杂岩 in Fennoscandia的年代为2.6Ga (Tichomirowa et al .， 2013)，所以太古代。这是我找到的最古老的。< / p >
Another mechanism that could produce limestones in ancient eons is described by user @BillDOe in this related answer:
Once life evolved in the world's oceans, the vast majority of limestone formation has been through the organic process. However, before life did evolve, limestone formed through an inorganic process where rain water falling through a CO2-rich atmosphere reacted to form a weak carbonic acid solution that then reacted with calcium-containing minerals to form calcites. This then washed into the world's oceans to form limestone deposits.
The premise comes from this stanford.edu work and is a bit controversial because there are no proofs limestones formed by this mechanism.
International Stratigraphic Chart image
M. Tichomirowa, M.J. Whitehouse, A. Gerdes, J. Götze, B. Schulz, B.V. Belyatsky (2013): "Different zircon recrystallization types in carbonatites caused by magma mixing: Evidence from U–Pb dating, trace element and isotope composition (Hf and O) of zircons from two Precambrian carbonatites from Fennoscandia", Chemical Geology, Volume 353, Pages 173-198, ISSN 0009-2541. https://doi.org/10.1016/j.chemgeo.2012.11.004.
