It is where a complex association of two igneous rock types exist, granite and gabbroic diorite. Intrusive rock bodies are masses of magma which have cooled and crystallized below the earth's surface, as opposed to having formed from a volcanic eruption and then cooled on the surface. Note: "Diorite is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock). It is intermediate in composition between low-silica gabbro and high-silica granite."
Note: "Diorite is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock). It is intermediate in composition between low-silica gabbro and high-silica granite."