- Extrusive rock (Wikipedia)
Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. In contrast, intrusive rock refers to rocks formed by magma which cools below the surface.
- Trobriand Plate (Wikipedia)
The Trobriand Plate was, and likely is, an independent microplate between New Guinea and the Solomon Islands. It has some unique geology, having the presence of the youngest metamorphic core complexes on earth. If there is presently active subduction between it and the Solomon Plate, at the Trobriand Trough, it continues to be an active microplate. Otherwise in the latest tectonic models it has merged with the Solomon Sea Plate, which becomes somewhat larger than predicted by Bird’s 2003 model of Tectonic Plates. As a smaller Solomon Sea Plate is totally underwater, global positioning data can not resolve this issue. The area of the plate is associated with earthquake and volcanic activity as part of the Pacific Ring of Fire.