Module 3: The Geosphere: Earth Materials and Geologic Time

crystallization

the formation of crystals from a gas or liquid where atoms are bonded together into orderly, repeating, three-dimensional structures through cooling of a liquid or precipitation of a solid from a solution

magma

molten rock

lava

magma that has erupted above ground

Igneous Rocks

form from magma

extrusive

formed from lava (erupted magma)

intrusive

formed from magma crystallizing below ground

mafic

a term describing rocks or magmas rich in iron and magnesium

felsic

a term describing a light-colored igneous rock, lava, or magma with high silica content and low iron and magnesium content

Bowen’s reaction series

the evolution of magma chemistry during cooling

erosion

the movement of flowing water, wind, or ice, or simply by gravity as in a landslide

deposition

sediments are laid down

Sedimentary Rocks

rock lithified from deposits of sediment

depositional environments

the environment in which sediments accumulate and often become sedimentary rocks

lithification

the process of converting sediment into rock by compaction, cementation, and crystallization

clastic

particles deposited physically, by wind, running watge

sedimentary structures

evidence of sediment transport processes left in the rock record, such as ripple marks or cross beds

chemical sediments

sediments that originate from chemical weathering processes that partially or wholly dissolved mineral

evaporites

crystalline sedimentary deposits that form evaporating waters

biological sediments

accumulate from the carcasses of organisms

regional metamorphism

occurs at moderate to deep levels under moderate to ultra-high pressures and high temperatures

high-pressure metamorphism

produced by continent-continent collision, occurs at high pressures

contact metamorphism

affects a thin zone of country around an ig

seafloor (hydrothermal) metamorphism

occurs at mid-ocean ridges where intruding magma drives seawater circulation through extruded basalts

Metamorphic Rocks

rock that has been altered by heat or pressure so that its texture or composition has been transformed

foliation

a set of planes, produced by deformation, in a metamorphic rock; the planes can be either flat or wavy; formed when minerals are arranged in a parallel fashion as crystals grow under conditions of immense rock pressure