Skeletal - Calcareous Algae - Rhodophytae (B/2/Hol/Eni)
 2.5x
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 5x
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 2.5x
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 2.5x cross nicols
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 5x
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 10x
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 2.5x
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 2.5x wave plate
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 5x
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 5x wave plate
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 2.5x
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 2.5x wave plate
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| Outstanding feature |
Fibrous aragonite cementing |
| Folk Classification |
Halimeda biosparite |
| Dunham Classification |
Halimeda bioclastic grainstone |
| Common Grains |
Halimeda, foraminifera, gastropods and coral fragments |
| Sorting |
Well sorted |
| Rounding |
Some rounding |
| Micritization & envelopes |
Not obvious |
| Cement & diagenetic fabric |
Fibrous aragonite void fill, regular fibers filling gastropods & coating grains including magnesium calcite foraminifera |
| Porosity |
45% interparticle |
| Depositional Setting |
High energy reef margin |
| Diagenetic history |
Marine cementation |
Sample from 0.4 ft down in the Par 15 Well from the margin of Eniwetok Atoll in the Marshall Islands of the Pacific. Note the fantastic fibrous cements binding coral fragment, gastropods and halimeda flakes. Even the high magnesian calcite foraminifera is the site of aragonite cementation.
Thursday, November 11, 2021