Randomly Interpenetrating Radial Calcitic Ooids(O/31)
10x
|
2.5x
|
5x
|
5x
|
2.5 cross nicols
|
10x wave plate
|
10x wave plate
|
2.5 wave plate
|
5x wave plate
|
5x wave plate
|
Outstanding feature |
Radial calcitic ooids, crinoid ossicles and blocky equant spar |
Folk Classification |
Oosparite |
Dunham Classification |
Oolitic Grainstone |
Common Grains |
Ooids, & crinoid ossicles |
Sorting |
Good |
Rounding |
Good |
Micritization & envelopes |
Most grains |
Cement & diagenetic fabric |
Bladed isopachus rims & equant spar overgrowths on crinoids |
Porosity |
Dense |
Depositional Setting |
Open marine high energy shoal water |
Diagenetic history |
Cemented by large equant spar, much of it overgrowths on echinoids |
Sparse isopachus rim cements are probably related to initial freshwater cements that originated from dissolution of original aragonite and calcite. The radial calcite ooids accumulated adjacent to a high energy setting. Note radial character of the crystals in the ooid layering is somewhat obscure. Darkened spots within bioclastic layers are after cyanobacteria colonies that caused local micritization. Note the well developed large calcite spar overgrowths on echinoid fragments.
Thursday, November 11, 2021