Chert nodules (black) in chalk,formed by concretionary enrichment of silica after the chalk has been deposited in marine environments. Cretaceous formation of the Avedat,Negev desert,Israel | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 5125 px × 3417 px |
Model Release : | Non requis |
Restrictions : | - |