Rock microstructure intrusions are a result of uninterrupted slow cooling. When a rock cools too quickly the liquid freezes into a solid glass, or crystalline groundmass. Often vapor loss from a magma chamber will cause a porphyritic texture. "Embayments" or 'corroded' margins to phenocrysts infer that they were being resorbed by the magma and may imply addition of fresh, hotter magma. Ostwald ripening is also used to explain some porphyritic igneous textures, especially orthoclase megacrystic granites. A crystal growing in a magma adopts a habit (see crystallography) which best reflects its environment and cooling rate. The usual phenocryst habit is the ones
Magma Geopark magma and high mountains. Through millions of years, glaciers helped to form the landscape we see in the area today. The main rock type is anorthosite, which is more common on the Moon than on the surface of Earth. Magma Geopark has several nature, culture, history and industrial attractions for both local visitors or tourists. The area has wide network routes and locations for outdoor activities, such as hiking, biking, climbing, kayaking. The geoVR virtual exhibition is now ready for the public in the centre of Egersund. From 1 June at the office located in Elvegaten 23 you can also