Carbonate diagenesis: A celebration of the work of John Anthony Dawson (Tony) Dickson.

Magnesian Limestone zoned dolomite (red and non-luminescent zones) now partly dedolomitized), calcite (yellow luminescence), blue luminescent albite has non-luminescent overgrowths) Mansfield Quarry, Nottinghamshire. Modern tropical carbonate sediments are generally aragonite and high-Mg calcite with high porosities (Enos & Swatsky, [16]), yet ancient carbonates (Miocene and older) are generally calcite or dolomite with far lower porosity. Dissolution of aragonite and Mg calcite with precipitation of calcite cements with 2-8 mol% MgCO SB 3 sb occur in sea water undersaturated with respect to aragonite and high-Mg calcite, but supersaturated with respect to low-Mg calcite. The Xiong et al. compilation shows that the cycles of aragonite/high-Mg calcite were more variable than previously recognised, with the first inferred transition from a high-Mg calcite to low-Mg calcite sea occurring during early Cambrian stage 3. [Extracted from the article]