GEORGE BERNARD / SCIENCE PHOTO LIBRARY GEORGE BERNARD / SCIENCE PHOTO LIBRARY
Oolitic limestone. Cut surface of oolitic lime- stone, a type of sedimentary rock derived from coral reefs. The numerous, round particles in this rock are "ooliths". These form in shallow tropical seas from fragments of shell that act as nuclei for the precipitation of dissolved calcium carbon- ate (CaCO3). Some of the shell nuclei can still be seen here. After growing to up to 2mm wide, ooliths fall into the layer of carbonate sand on the sea bed, and eventually become compacted into limestone rock. This 160 million year old sample from France was formed during the Jurassic period, when the dinosaurs were at their peak. Magnification x2 at 35mm size.
Model release not required. Property release not required.