Answer:
Deep underground, beneath an extinct volcano
Explanation:
Diorite results from the partial melting of a mafic rock above a subduction zone. It is found in volcanic arcs, and in cordilleran mountain building, such as in the Andes Mountains.
Diorite is formed deep within the Earth's crust from cooling magma that never made it to the surface. It usually occurs as quite small intrusions often associated with larger intrusions like granite. Slow cooling produces the large crystals.