Record and time of Neoproterozoic glaciations on Earth
全球新元古代冰期的记录和时限

The chemical carbonates are susceptible to post-depositional alteration, especially diagenetic alteration after chemical deposition. Potential diagenetic fluids include seawater, meteoric water and hydrothermal fluid. Sedimentary carbonates are lithified after a series of diagenetic alteration such as compaction, dissolution, precipitation, recrystallization, and cementation. The primary mineral and geochemical signatures can be either preserved or changed during the post-depositional alteration, which are controlled by the composition of diagenetic fluid and the diagenetic temperature. In many cases, however, the post-depositional alteration may impart a secondary signal, so that the chemical signature of sedimentary carbonate no longer accurately reflects its primary property. Thus, a thorough understanding of diagenetic pathways and extents is necessary when interpreting the chemical archives recorded in the carbonate with respect to the construction of paleoenvironment and paleoclimate.