- Bioclastic Sedimentary Rocks are not composed of weathered
rock fragments.
Rather, they are comprised of the organic remains of animals (mostly marine)
or vegetation in combination with a mineral cement.
- The environment of formation is typically water; marine for rocks containing
shell and coral fragments; swamps for coal, which contains plant remains.
- Bioclastic rocks such as Fossil Limestone, Coquina and Chalk, which contain
the mineral Calcite in the form of shells and corals, often form in shallow
seas or over continental shelf regions.
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Fossil Limestone
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Coquina
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Chalk
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- Bituminous Coal, a Bioclastic Sedimentary Rock, is often found in layers
with other sedimentary rocks. Remains of plants that have fallen into swamps
are altered over millions of years into carbon. The overlying layers of rocks
compress and compact the vegetation forming coal.
