Ooids Replaced by Chert - Ordovician (O/41/Ord/Pa)
 2.5x
|
 5x
|
 10x wave plate
|
 2.5 cross nicols
|
 5x cross nicol
|
 10x wave plate
|
 2.5 wave plate
|
 5x wave plate
|
| Outstanding feature |
Chert replaces radial ooids & fibrous cement |
| Folk Classification |
Chertified Oosparite |
| Dunham Classification |
Chertified Oograinstone |
| Common Grains |
Ooids |
| Sorting |
Well Rounded |
| Rounding |
Well Sorted |
| Micritization & envelopes |
Grains at nucleae have micrite envelopes |
| Cement & diagenetic fabric |
Almost complete replacement by chert |
| Porosity |
1% intercrystalline |
| Depositional Setting |
High energy shoal |
| Diagenetic history |
Complete chertification of ooid cortex & cement |
Striking replacement of radial calcitic ooid cortex concentricly layered about nucleae of both an mozaic of equant authogenic quartz and larger original felspar and quartz grains.
Thursday, November 11, 2021