What are greenstone belts?
Q: What are greenstone belts?
A: Greenstone belts are large regions of very ancient metamorphosed volcanic rocks that were originally formed of igneous rocks, such as basalt.
Q: Why are these belts called greenstone?
A: The name comes from the green colour of the minerals in the rocks, such as chlorite, actinolite, and other green amphiboles.
Q: Where were greenstone belts formed?
A: Greenstone belts were formed at ancient oceanic spreading centers and in volcanic island arcs.
Q: Are greenstone belts found only in oceans?
A: No, those greenstone belts which formed in ancient oceans are now found on land in Archaean and Proterozoic cratons between granite and gneiss bodies.
Q: What type of rocks are found in greenstone belts?
A: The rocks are mafic, meaning they are high in magnesium and silica.
Q: How long can greenstone belts be?
A: Greenstone belts can be several thousand kilometres long.
Q: How were greenstone belts formed?
A: Greenstone belts were originally formed of igneous rocks, such as basalt, which were later metamophosed, with minor sedimentary rocks in-between the volcanic formations.
