11. Volcanic ashes and lavas accumulate on the surface, and igneous intrusions enter from below. 12. The fields are associated with igneous intrusions . 13. These are igneous intrusions of magma which formed within the existing Beacon Hill and Bradgate Formations. 14. Instead, the cooled and solidified igneous mass crystallises within the crust to form an igneous intrusion . 15. Mountain ranges associated with laccoliths and other igneous intrusions on the Colorado Plateau, southwestern United States. 16. Tungsten ore deposits are predominantly magmatic or hydrothermal in origin and are associated with felsic igneous intrusions . 17. Skaergaardite is associated with igneous intrusions containing well-preserved, oxide-rich, tholeiitic gabbro. 18. Two productive pools were found, both in the Sespe Formation, separated by an igneous intrusion . 19. There are various igneous intrusions including pegmatite, as well as " bands " of gneiss and schist. 20. It occurs in high temperature regional metamorphic rocks and in the skarns within contact aureoles around igneous intrusions .
