Skeletal Grain types

Green Algae

1. Koninckopora

Grainstone with fragments of the calcitic dasyclad alga Koninckopora (Hunts Bay Oolite, Gower) including bioclasts with micritic envelopes due to bioerosion.

Visean (Holkerian), Mississippian, South Wales, UK

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2. Koninckopora

Grainstone with fragments of the calcitic dasyclad alga Koninckopora from a Visean carbonate ramp (Hunts Bay Oolite, Gower).

Visean (Holkerian), Mississippian, South Wales, UK

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3. Koninckopora

Transverse sections of the calcitic dasyclad alga Koninckopora in Visean carbonate ramp facies associated with brachiopods.

Visean (Holkerian), Mississippian, South Wales, UK

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4. Kamaenid

Kamaenella boundstone from Visean carbonate ramp. The peloids surrounding the framework could be in situ precipitated. The problematic organism is supposed to be a green alga belonging to a group of algae that were the main sediment contributors in Visean limestones, thriving in shallow platform interior lagoon and forming bioherms (Horbury, 1992).

Visean, Hunts Bay Oolite, Gower, South Wales, UK

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5. Kamaenid

Kamaenella boundstone from Visean carbonate ramp. The peloids surrounding the framework could be in situ precipitated. The problematic organism is supposed to be a green alga belonging to a group of algae that were the main sediment contributors in Visean limestones, thriving in shallow platform interior lagoon and forming bioherms (Horbury, 1992).

Visean, Hunts Bay Oolite, Gower, South Wales, UK

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6. Palaeoberesellid

Porous palaeoberesellid and Issinella alga grainstone from the Mississippian platform facies of the Karachaganak Field, Kazakhstan.

Visean, Karachaganak Field, Kazakhstan

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7. Calcisphere

Skeletal packstone of low energy protected environments containing calcispheres from the Lower Carboniferous of North England.

Mississippian, North England, UK

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8. Beresellid

Beresellid algae bafflestone with numerous transversal sections and two longitudinal sections: Beresella (on the left) and Uraloporella (on the right).

Pennsylvanian, Asturias, N Spain, cf. Bahamonde et al. (2015, 2017)

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9. Phylloid

Clotted peloidal micrite microbial boundstone with phylloid algae, automicrite and blocky calcite spar. Phylloid algae were aragonitic and are preserved as biomoulds with thin micrite envelopes.

Pennsylvanian, Asturias, N Spain, cf. Bahamonde et al. (2015, 2017)

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10. Phylloid

Skeletal peloidal grainstone with phylloid algae, calcispheres and ostracods.

Pennsylvanian, Asturias, N Spain, cf. Bahamonde et al. (2015, 2017)

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11. Donezellid

Clotted peloidal micrite boundstone with Donezella (supposedly green alga but likely with sponge affinities) branching and forming the framework supported by the peloidal micrite. Primary cavities are occluded by radiaxial fibrous cement.

Pennsylvanian, Asturias; cf. Della Porta et al. (2002, 2003, 2004)

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12. Donezellid

Branching Donezella (green alga?) framework with calcite cement within the delicate framework porosity.

Pennsylvanian, Asturias; cf. Della Porta et al. (2002, 2003, 2004)

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13. Donezellid

Donezella (green alga?) delicate framework with micrite encrustations and radiaxial fibrous cement in the primary framework porosity.

Pennsylvanian, Asturias; cf. Della Porta et al. (2002, 2003, 2004)

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14. Donezellid

Skeletal condensed grainstone with in the centre a foraminifer (Tetrataxis) and in the centre left a reworked fragment of supposed green alga Donezella.

Pennsylvanian, Asturias, N Spain, cf. Bahamonde et al. (2015, 2017)

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15. Donezellid

Clotted peloidal micrite boundstone with micrite encrusting and strengthening the delicate framework formed by Donezella and Praedonezella supposed algae. Radiaxial fibrous calcite filled the primary framework.

Pennsylvanian, Asturias; cf. Della Porta et al. (2002, 2003, 2003)

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16. Donezellid

A skeletal grainstone containing cm-size patches of clotted automicrite and Praedonezella framework.

Pennsylvanian, Asturias, N Spain, cf. Bahamonde et al. (2015, 2017)

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17. Phylloid

Packstone consisting of phylloid algae fragments. The former aragonite algae have been replaced by calcite spar.

Pennsylvanian, Yucca Mound, New Mexico, USA

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18. Calcisphere

Skeletal wackestone from restricted lagoon facies with a calcisphere in the upper central part from the Pennsylvanian of Asturias.

Pennsylvanian, Asturias, N Spain, cf. Bahamonde et al. (2015, 2017)

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19. Mizzia

Grainstone including cross section of the dasyclad alga Mizzia. The original aragonite has been removed and replaced by calcite cement. Most dasyclads are indicative of well-lit depositional environments shallower than 20 m.

Permian, West Texas, USA

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20. Dasyclad

Skeletal peloidal packstone to wackestone with an axial cross-section of Palaeodasycladus mediterraneous associated with foraminifera (Siphovalvulina, Haurania/Amijiella, textularids) from Lower Jurassic lagoon facies.

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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21. Dasyclad

Skeletal peloidal packstone to wackestone with a transversal cross-section of Palaeodasycladus mediterraneous and Siphovalvulina foraminifer from Lower Jurassic lagoon.

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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22. Dasyclad

Oncoid and cortoid packstone with an oblique cross-section of Palaeodasycladus mediterraneous (with geopetal sediment infill) from Lower Jurassic lagoonal facies.

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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23. Dasyclad

Wackestone from a lagoonal facies with the dasyclad Clypeina jurassica (Upper Jurassic).

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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24. Charophytes

Skeletel packstone to wackestone of lacustrine deposits including gastropods, ostracod fragments and green algae Charophytes oogonia (gyrogonite) and stems.

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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25. Charophytes stems

Cross sections of Charophyte stems.

Lower Cretaceous, Cameros Basin, N Spain

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26. Dasyclad

Coated grain peloidal packstone to wackestone containing fragments of the dasyclad alga Actinoporella (Cretaceous).

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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27. Dasyclad

Coated grain peloidal wackestone containing fragments of the dasyclad alga Actinoporella (Cretaceous).

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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28. Dasyclad

Coated grain peloidal skeletal packstone containing fragments of the dasyclad Actinoporella (Cretaceous).

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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29. Halimedacean

Halimedacean alga from Cretaceous lagoonal facies.

Cretaceous, Turonian, Miskar Field, offshore Tunisia

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30. Dasyclad

Packstone with dasycladacean algal fragments from Cretaceous deposits of the Thamama Fm., Oman.

Cretaceous Thamama Formation, Oman

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31. Halimedacean

Stained thin section of Halimedacean alga from Turonian facies.

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32. Halimedacean

Halimedacean alga from Cretaceous facies.

Cretaceous, Turonian, Miskar Field, offshore Tunisia

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33. Dasyclad

Slightly oblique longitudinal section of a dasycladacean alga from Upper Cretaceous, Simsima Formation, Abu Dhabi. Note that the originally finely crystalline aragonite walls have been replaced completely by calcite spar (sparite).

Upper Cretaceous, Simsima Formation, Shah Field, Abu Dhabi, UAE

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34. Dasyclad

Cross-section of a dasycladacean alga from Eocene Mukta Field, offshore India.

Eocene, Bassein Formation, Mukta Field, Bombay High, offshore India

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35. Dasyclad

Condensed packstone with a fragment of dasyclad alga, benthic foraminifera, echinoderms and quartz grains (Eocene).

Thin section kindly provided by T. Geel, Vrije Universiteit, Amsterdam

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36. Halimeda

Recent Halimeda from the Bahamas. Field of view approximately 13 mm.

Recent, Great Bahama Bank

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Koninckopora

Koninckopora

Koninckopora

Kamenella

Kamenella

beresellid alga Uraloporella

beresellid alga Beresella

phylloid alga

clotted peloidal micrite

phylloid alga

Donezella

clotted peloidal micrite and microspar

Donezella

calcite cement

Donezella

radiaxial fibrous cement

Donezella

foraminifer Tetrataxis

Praedonezella

radiaxial fibrous calcite cement

Praedonezella

fusulinid foraminifer

Palaeodasycldus mediterraneous

foraminifer Haurania/Amijiella

Palaeodasycladus mediterraneous

Siphovalvulina

Palaeodasycladus mediterraneous

Clypeina jurassica

gyrogonite of Charophytes

Actinoporella

Actinoporella

Actinoporella

Green Algae

CLOSE

Koninckopora

Koninckopora

Koninckopora

Kamenella

Kamenella

beresellid alga Uraloporella

beresellid alga Beresella

phylloid alga

clotted peloidal micrite

phylloid alga

Donezella

clotted peloidal micrite and microspar

Donezella

calcite cement

Donezella

radiaxial fibrous cement

Donezella

foraminifer Tetrataxis

Praedonezella

radiaxial fibrous calcite cement

Praedonezella

fusulinid foraminifer

Palaeodasycldus mediterraneous

foraminifer Haurania/Amijiella

Palaeodasycladus mediterraneous

Siphovalvulina

Palaeodasycladus mediterraneous

Clypeina jurassica

gyrogonite of Charophytes

Actinoporella

Actinoporella

Actinoporella