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Non- Ooliths
skeletal Aggretates
Plant Pellets

Animal }Green Calcareous

Foramol Red algae
Corals
Molluscs
Benthonic forams
Bryozoans
Barnacles
Other (i.e. echinoids)

Chlorozoan

Figure 4.2 – Classification of carbonate grain types by Lees & Buller (1972). The grey parts
illustrates importance or dominance.

red algae almost no non-skeletal and vegetal particles. The classification is illustrated in figure 4.2.

Simone & Carannante (1988) describe the temperate platforms that are associated with foramol. Unlike
chlorozoan carbonates foramol is believed to be deposited in temperate environments. A relation between
different water depths and fossil types is given, reaching from sea meadow and molluscs at shallower
depths to algae, bryozoans and forams in deeper parts. Because of the temperate nature of foramol
platforms, they usually can not keep up with a sea level rise — like tropical platforms do — and will
eventually drown.

Reefs in both tropical and non-tropical regions have a significant contribution from carbonate sediments
(Carannante et al., 1988). Rhodalgal sediments — consisting of encrusting coralline algae and bryozoans
— are mainly found on temperate shelves, however a study of several both modern and ancient foramol
platforms in southeast Asia and Australia by Wilson & Vescei (2005) supports the presence of foramol
platforms in tropical regions.

4.2.2 Fossil content

As seen in the previous section, fossil content of a calcarenite can give indications of its origin. The results
of the analysis of the thin sections in cooperation with Dr. X. Marquez are given below. Flu¨gel (2010) is
consulted for information on the type of fossils.

Bryozoans

Bryozoans, also known as moss animals, are a type of small invertebrate (’without a backbone’) animals
that feed themselves by sieving food using a network of tentacles. Almost all bryozoans form colonies.
Figure 4.3a shows an example of a common types of bryozoans as seen in the thin sections.

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