Outstanding feature |
Algal laminae with pseudomorphs of gypsum filled by calcite spar |
Folk Classification |
Micrite layer interbedded with pelsparite. The spar pseudomorphs gypsum blades |
Dunham Classification |
Mudstone layer interbedded with pellet packstone. Calcite cement pseudomorphs gypsum blades |
Common Grains |
Pellets and calcite blades pseudomorph gypsum |
Sorting |
Poor |
Rounding |
Poor |
Micritization & envelopes |
Micritic intraclasts and pellets |
Cement & diagenetic fabric |
Calcite blades pseudomorph gypsum rossettes |
Porosity |
None |
Depositional Setting |
Upper tidal flat to upratidal tidal flat with algal mats overlieing a gypsum mush |
Diagenetic history |
Replacement of gypsum by calcite |
Fossil Forest, Jurassic age sediments from Lullworth Cove, Dorset in the U.K. Fabric replacement by micrite and spar; gypsum blades replaced by calcite spar. This thin section that cuts across both the fabric of algal stromatolites and their associated diagenetic fabric from an intertidal to supratidal setting.