Thrombolite

Modern thrombolites in Lake Clifton, Western Australia

Jurassic thrombolite formed around a tree trunk; Purbeck Formation, Isle of Portland, Dorset, England.

Thrombolites are clotted accretionary structures formed in shallow water by the trapping, binding, and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria. Stromatolites are similar but consist of layered accretions.

External links

Wikimedia Commons has media related to Thrombolites.

• Thrombolites and stromatolites; two distinct types of microbial structures