Skeletal - Calcareous Algae - Chlorophyta (Green algae) (B/15/Ple/En)
.jpg) 2.5x
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 2.5x cross nicols
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 2.5x wave plate
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 5x
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 5x wave plate
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 10x
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| Outstanding feature |
Startling fibrous aragonite cements coating bioclasts |
| Folk Classification |
Halimeda biosparite |
| Dunham Classification |
Halimeda grainstone |
| Common Grains |
Halimeda, gastropods, and corals |
| Sorting |
Well sorted grains |
| Rounding |
Well rounded grains |
| Micritization & envelopes |
No obvious micrite envelopes |
| Cement & diagenetic fabric |
Early fibrous marine crusts enclosed grains |
| Porosity |
30% |
| Depositional Setting |
High energy carbonate grain shoal |
| Diagenetic history |
Subject to marine cementation |
Note that the fibrous cements enclose and coat Halimeda flakes, and other aragonite fossils but tend not to form on the high magnesium calcite foraminifera. Note the varying fill of the tubes in the Halimeda flakes and varying early disolution of some of these grains; sometimes the matrex and sometimes the tubes. Note the micrite perched on some of the fibrous aragonite cements.
Thursday, November 11, 2021