Fossil stromatolite. This polished slice through a rock shows layers of a fossilised stromatolite. Each layer began as a covering of blue-green algae (cyanobacteria),which captured grains of sediment and became mineralised. As more layers were added to the top over thousands of years,a stromatolite,or rocky mound,gradually formed. Fossilised stromatolites have been found within rocks as old as 3.5 billion years. This sample measures 300 millimetres across | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 5050 px × 3536 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |