Nodules in geology are more or less round concretions, compact bodies formed by accretion within a rock. The nodule in this example is Rhyolitic, a volcanic rock type. While it lithifies cracks and voids open up inside, later to become filled with a siliceous precipitate (chalcedony). Cut in half and polished fascinating configurations are displayed, like in this example from West Australia. Actual size is that of a small pear. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Wiersma, Dirk |
Taille de l’image : | 5616 px × 3744 px |
Model Release : | Non requis |
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