Ooids - Aragonite Cortex Dissolving - Sparse Calcite Cement - Pleistocene (O/16/Ple/Bah)
10x
|
2.5x
|
2.5x
|
5x
|
5x
|
5x wave plate
|
Outstanding feature |
Mix of high energy ooids, grapestones & bioclasts |
Folk Classification |
Well sorted bio-oosparite |
Dunham Classification |
Well sorted bio-oograinstone |
Common Grains |
Ooids, bioclasts and grapstones |
Sorting |
Well sorted |
Rounding |
Well rounded |
Micritization & envelopes |
Ooids & micritization of bioclasts occurs |
Cement & diagenetic fabric |
Freshwater cements |
Porosity |
10-15% intergranular primary porosity |
Depositional Setting |
High energy shoal |
Diagenetic history |
Freswater diagenesis of aragonite grains |
Striking high energy concentric aragonite ooid grains and bioclasts that accumulated on the NW margin of the New Providence Pleistocene high energy shoals. Note the voids within the cortex of ooids that are the product of dissolution related to the influx of freshwater during the uplift and subaerial exposureof these shoals in the Holocene.
Thursday, November 11, 2021