Magma formsfrom partial melting of mantle rocks. As the rocks move upward (or have water added to them), they start to melt a little bit. These little blebs of melt migrate upward and coalesce into larger volumes that continue to move upward. They may collect in a magma chamber or they ...
The process, called relamination, starts at the edge of a continental plate, where an oceanic plate is diving under the continental plate and magma is rising to form a volcanic arc. As the oceanic plate dives, it drags down sediment, lava and plutonic rock from the edge of the arc. As ...
anhedral (allotriomorphic) A morphological term referring tograins in igneous rocks which have no regular crystalline shape. Anhedral forms are developed when a crystal's free growth in a melt is inhibited by the presence of surrounding crystals. ...
A pluton that develops when molten magma flows horizontally between rack layers, bulging the overlying layers upward. a. dike b. sill c. laccolith d. lava plateau Sections of the geologic timescale are defined by: A. how close the ...
An extreme carbon-releasing mechanism can occur when magma invades a sedimentary basin containing extensive deposits of fossil fuels. Fortunately, this is an infrequent phenomenon. But it has nevertheless happened at times, including an episode 250 million years ago at the end of the Permian Period...