A dyke is formed when a molten rock forces its way vertically through faults in the existing country rock. The country rock here is granodiorite, an igneous rock similar to granite, formed about 600 million years ago. Later this country rock was intruded by a dyke, part of a dyke swarm, of a rock similar to basalt called dolerite. As a liquid magma, the dolerite forced its way up through the granodiorite and then cooled rapidly into a medium grain rock. Dolerite is identified by its mineral profile and grain size. Photographed in Perros Guirec, Brittany, France. | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Chillmaid, Martyn F. |
Bildgröße: | 3648 px × 5472 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |