Home > Flashcards > Geology > Understanding Earth

Details Title: Understanding Earth Description: Chapter 5 Total Flash Cards: 28 Created: 09/27/2005 00:02:36	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term Intrusive Igneous Rock Definition rock that has forced its way into surrounding rock Term country rock Definition rock that surrounds intrusive igneous rock Term pyroclasts Definition form when broken pieces of lava are thrown high into the air Term volcanic ash Definition estremely small fragments, usually glass, that form when escaping gases force a fine spray of magma from a volcano Term pumice Definition a frothy mass of volcanic glass with a great number of vesticles (vesticles are holes that remain after trapped gas has escaped from the solidifying melt) Term obsidian Definition volcanic rock that contains only tiny vesicles and so is solid and dense Term porphyry Definition igneous rock that has a mixed texture in which large crystals "float" in a predominantly fine crystalline matrix Term basalt Definition an extrusive rock formed from lava Term granite Definition 70% silica Term extrusive igneous rocks Definition rapid cooling of earth's surface produces the finely grained texture or glassy appearance of these Term felsic rock Definition rocks that are poor in iron and magnesium and rich in minerals that are high in silica Term rhyolite Definition the extrusive equivalent of granite Term intermediate igneous rocks Definition rocks that are neither as rich in silica as felsic rocks nor as poor in it as the mafic rocks Term granodiorite Definition a light-colored felsic rock that looks something like granite Term dacite Definition the volcanic equivalent of granodiorite Term felsic rocks Definition quartz, potassium felspar, plagioclase feldspar, muscovite (mica) Term mafic Definition biotite (mica), amphibole group, pyroxene group, olivine Term mafic rocks Definition rocks that are high in pyroxenes and olivines. relatively poor in silica but rich in magnesium and iron Term ultrafmafic Definition rocks that consist primarily of mafic minerals and contain less than 10% FELSPAR Term viscosity Definition the measure of a liquid's resistance to flow Term partial melting Definition occurs because the minerals that compose a rock melt at different temperatures Term decompression melting Definition produces the greatest volume of molten rock anywhere on earth Term magma chambers Definition magma-filled cavities in the lithosphere that form as ascending drops of melted rock push aside surrounding solid rock Term magmatic differentiation Definition a process by which rocks of varying composition can arise from a uniform parent magma Term fractional crystallization Definition the process by which the crystals formed in a cooling magma are segregated from the remaining liquid Term sill Definition tabular, sheetlike body formed by the injection of magma between parallel layers of preexisting bedded rock Term dikes Definition the major route of magma transport in the crust Term pegmatites Definition veins of extremely coarse-grained granite cutting across a much finer grained country rock