The beauty of shells

Ammonites are an extinct group of cephalopods that populated the oceans for more than 300 million years. Their carbonatic shells are often used to reconstruct palaeo-ocean seawater temperatures. Here you see a thin section under the fluorescence microscope. The shell fluoresce in bright green colour while the calcite the fills the rest of the shells fluoresce with less intensity. In the centre of the image one can see the initial chamber most likely formed in the egg. After hatchling the ammonite shell growth and devided its shell in several chambers. the whole shell act as abuoyancy device comparable with a submarine.