ABSTRACT
In practice, rock type, process and resultant rock condition and landforms are intimately linked through a rock cycle whose components also share specific plate and global locations. Rock-forming minerals are the crucial link between broadly homogeneous magmas derived from the upper mantle and particular heterogeneous assemblages which form a distinct lithology or rock type. Rock-forming and recycling processes are tied closely to tectonic supercontinental cycles and constitute several interconnected sub-cycles in their own right. A concern for rocks and their geochemistry underpins our understanding of not only rock formation but also soils, nutrient cycles and lithospheric material exchanges with the biosphere, atmosphere and oceans – all of which are dynamic, evolving material systems sourced from Earth's rocks. The violent exhalation of gases, magma and fragmented rock dramatically transforms volcanic products from lava flows over surrounding landscapes into airborne tephra, rained out over a large area.
