BIOGENIC ROCKS

Formed from organic debris or materials resulting from biochemical action. These materials can be
shells, carapaces, diatom skeletons, radiolaria, spongiaria, organic microstructures, among others.

conquiferous limestone

Formed from the cementation of rocks
that accumulate in shallow water.
Shells result from the extraction of
calcium carbonate from the sea by
some living beings.

reef limestone

Is formed by the accumulation of
corals (their polyps) that fix
calcium carbonate.

biogenic limestone

Formed by the precipitation of calcium
carbonate, which can be triggered by
the decrease in CO2 due to the
activity of photosynthetic beings,
namely algae.

coal

Coals are formed when deposition of
continental organic matter (flora in this case)
occurs in coastal lagoon or lake basins.
Organic debris is covered by a thin layer of
sediment that creates an anaerobic
environment (bacteria transform organic
matter into a plant paste called peat).
progressive sinking promotes an increase in
pressure and temperature, causing the death
of bacteria. Under these conditions, water
and gases are lost, leading to an enrichment
in carbon, creating coal.