A greenstone belt is a region of ancient, metamorphosed volcanic and sedimentary rocks, typically of Archean to Proterozoic age, often associated with significant mineral deposits such as gold and nickel. Greenstone belts are important in understanding the early Earth’s tectonics, the formation of the continental crust, and the processes of mineralization.
Reference: de Wit, M. J., & Ashwal, L. D. (1997). Greenstone Belts. Oxford Monographs on Geology and Geophysics.