Final answer:
In the rock cycle, A represents igneous rock, and B symbolizes the process of metamorphism. The cycle includes formation processes for igneous, sedimentary, and metamorphic rocks. Igneous rocks are classified as intrusive or extrusive, and their formation relates to various tectonic environments.
Step-by-step explanation:
In this model of the rock cycle, A represents an igneous rock, and arrow B represents the process of metamorphism. The rock cycle involves the transformation of rocks through various geological processes, including weathering, deposition, and lithification, which lead to the formation of sedimentary rocks; melting and crystallization, forming igneous rocks; and the influence of increased pressure and temperature, which creates metamorphic rocks.
Igneous rocks come in two main types: intrusive (or plutonic), which cool and solidify below the Earth's surface, and extrusive (or volcanic), which solidify at or above the Earth's surface. The composition of igneous rocks varies depending on the minerals they contain, which is dictated by the cooling history of the magma from which they crystallize.
Tectonic environments associated with igneous rock formation include mid-ocean ridges where basaltic lavas are extruded, subduction zones where andesite and rhyolite can form, and hotspots where we may find a variety of igneous types depending on the depth and composition of melting.