Skeletal - Bryozoan, Brachiopods, Echinoids & Trilobites (B/36/Ord/Ohio)
 2.5x
|
 5x
|
 2.5x
|
 2.5x
|
 2.5x
|
 5x cross nicols
|
 5x
|
 5x cross nicols
|
| Outstanding feature |
Bryozoan fragments in fine matrix |
| Folk Classification |
Bryozoan poorly washed biosparite |
| Dunham Classification |
Bryozoan packstone |
| Common Grains |
Bryozoan, Brachiopods, Echinoids & Trilobites in a lime mud matrix |
| Sorting |
Bimodal |
| Rounding |
Moderarately rounded |
| Micritization & envelopes |
None |
| Cement & diagenetic fabric |
Some spar dispersed in the mud |
| Porosity |
None |
| Depositional Setting |
Quiet water close to higher energy |
| Diagenetic history |
High Mg calcite resists alteration |
This sample of the Ordovician of Ohio is from an outcrop in the vicinity of Cinncinnatti from the Maysville Group. The setting was a shallow shelf which was sorted by storm waves that disarticulated the brachipods and broke up the skeletal materials. The mixed matrix is derived from to a mix of storm derived mud and the skeletal grains that were broken by the storms!
Thursday, November 11, 2021