endogenic system
consits of processes operating in Earth's interior, driven by heat and radioactive decay
exogenic system
consists of processes operating at Earth's surface, driven by solar energy and the movement of air, water, and ice
geomorphology
the study of Earth's surface landforms, specifically their origin, evolution, form, and spatial distribution; a subfield of both physical geography and geology
uniformitarianism
the guiding principle of Earth science, states that the same physical processes now active in the environment were operating throughout Earth's history
geologic time scale
a summary timeline that represents the full scope of Earth's history
stratigraphy
the scientific study of how rocks settle through superposition; use fossils of plant and animal remains to date rocks
seismic waves
shock waves that travel throughout the planet; speed of waves varies depending on the materials it passes through- slower through cold materials, plastic zones don't emit any waves
core
the innermost region of the Earth, divided into two regions: inner (solid iron) and outer (molten iron); a third of Earth's entire mass, but makes up only a sixth of its volume
mantle
composed of iron and magnesium oxides, this layer of Earth surrounds the core and has a lower and upper regions that make up about 80% of Earth's total volume; less dense and cooler towards the surface
Mohorovicic discontinuity (Moho)
the term used to describe the discontinuity between the uppermost mantle and the crust above it; named after a man who determines that seismic waves change as you reach this point because of different mineral compositions and densities
crust
lies above the Moho and is Earth's outer layer; thickness varies in different places on the planet; mostly composed of oxygen and silicon (74.3%), but there are six other main elemnts
lithosphere
used to describe rigid layers on the planet, includes the crust and the uppermost mantle and forms the rigid, cooler layer at Earth's surface
asthenosphere
lies within the hottest region of the mantle, 10% is molten in uneven patterns; convection currents in this zone cause lithosphere plates to shift
isostasy
the balance between the buoyancy and gravitational forces, explains the elevations of continents and the depths of ocean floors as determined by vertical movements of Earth's crust
geomagnetic reversal
occurs when the magnetic field fades to zero and then returns to full strength with polarity reversed (north and south magnetic poles are reversed); has occurred 9 times in the past 4 million years and hundreds of times in Earth's history
mineral
an inorganic, or nonliving, natural solid compound having a specific chemical formula and usually possessing a crystalline structure
rock
an assemblage of minerals bound together (granite), or a mass composed of a single mineral (rock salt) or of undifferentiated material (obsidian), or even solid organic material (coal)
igneous rock
a type of rock that solidifies and crystallizes from a molten state
magma
molten rock beneath Earth's surface and forms igneous rocks
lava
magma that has emerged at the surface, but retains magma characteristics
intrusive igneous rock
a type of igneous rock that occurs when magma intrudes into crustal rocks and then cools and hardens below the surface
extrusive igneous rock
a type of igneous rock that occurs when magma extrudes onto the surface as lava and then cools, normally resulting from volcanic eruptions and flows
granite
an example of a type of rock that forms when magma slowly cools beneath the surface, allowing time for crystals to form, and creates a coarse-grained rock
basalt
an example of a type of rock that forms when lava quickly cools at the surface forming finer-grained rocks; the most common extrusive igneous rock
pluton
general term for any intrusive igneous body that forms slowly in the crust, regardless of size or shape
batholith
the largest plutonic form, defined as an irregular-shaped mass with an exposed surface greater than 100 squared km; form many mountain ranges
sedimentary rock
derived from solar energy and gravity when loose grains and fragment (clasts) are cemented together
sediment
rock particles that have gone through weathering and erosion and are moved by gravity, wind, and water
lithification
occurs as loose sediment is hardened into solid rock; involves compaction of buried sediments as the weight of overlying material squeezes out the water and air between clasts and cementation which fills any remaining spaces and fuses the clasts together
limestone
the most common chemical sedimentary rock
metamorphic rock
type of rock that can be formed from igneous or sedimentary rocks when profound physical or chemical changes occur under pressure and increased temperature; normally more compact and harder than original rock
rock cycle
the name for the continuous alteration of Earth materials from one rock type to another
Pangaea
the name of a giant superontinent that existed approximately 225 million years ago
continental drift
term coined by Wegener to describe plate tectonics and their movement
plate tectonics
the theory that the lithosphere is divided into a number of plates that float independently over the mantle and along whose boundaries occur the formation of new crust, the building of mountains, and the seismic activity that causes earthquakes
mid-ocean ridge
the name of underwater mountain systems that form a 64000km chain
seafloor spreading
mechanism that builds mid-ocean ridges and drives continental movement; happens when an upwelling occurs and the new seafloor moves outward from the ridge as plates pull apart and new crust is formed
subduction zone
the area where when one portion of the lithosphere descends beneath another and dives downward into the mantle
transform fault
occurs when plates move past each other horizontally, forming a type of fault or fracture in Earth's crust
hot spot
places where plumes of magma rise from the mantle, producing volcanic activity as well as thermal effects in the groundwater and crust
geothermal energy
heat from Earth's interior
geologic cycle
cycle that summarizes Earth-atmosphere-ocean interface and is composed of three principle cycles: hydrologic, rock, and tectonic cycles
convergent boundaires
occur in areas of crustal collision and subduction
divergent boundaries
occur in areas of seafloor spreading, where upwelling material from the mantle forms new seafloor and lithospheric plates spread apart in a constructional process (along the East Pacific Rise)
transform boundaries
occur when plates slide past one another, usually at right angles to a seafloor spreading center