Modified from Surdam et al, 1989
This is part of the How To…series on carbonate rocks
Some general statements about the diagenesis of limestones during burial.
As sediment is buried, the combined effects of temperature, pressure and changing fluid composition act to lithify, overprint, and even obliterate all previous diagenetic histories. In limestones, the original sediment components and any early cements formed during seafloor or shallow meteoric diagenesis, are cemented, replaced by more stable carbonate phases, or recrystallized. Burial diagenesis is governed primarily by:
- Increasing temperature as a function of the local geothermal gradients,
- Increasing hydrostatic pressures with depth and sediment/water loads,
- Reactions resulting from organic maturation where pH buffering and changes in pCO2 drastically shift the stability of carbonates,
- Reactions involving silicates (especially clays) that also change fluid composition and pCO2,
- Tectonically induced faulting and folding that can alter permeability pathways, and
- Tectonic uplift that reduces ambient temperatures and pressures and exposes indurated rock to meteoric conditions.