Geology Review Sheet
7th grade Science 2018-19
geological time​ the measurement of time from the formation of Earth to the present - on a geologic time
scale - our lifespan is a blip, an insignificant length of time. You will hear people say things, “on a geologic
time scale …”
Earth Structure:
* geosphere or lithosphere​ the hard outer layer of Earth made of ​crust​ and hard, ​upper mantle​; broken
into ​tectonic plates
* atmosphere​ the air that surrounds Earth
* biosphere​ all the living things on Earth
* hydrosphere​ Earth’s water, both in the seas and on land
Earth’s Layers:
* crust​ the rigid outer layer of Earth
* ​lithosphere​ the hard outer layer of Earth made of ​crust​ and hard, ​upper mantle​; broken into ​tectonic
plates
* asthenosphere​ the fluid portion of the ​mantle​ that has special properties - it moves like silly putty
* mantle​ the layer of Earth below the crust; upper part is solid and lower part is semisolid
* inner core ​the solid layer at the center of the Earth
* outer core​ the molten layer at the center of the Earth
convection​ the heat transfer in a fluid which causes hot fluid to rise and cold fluid to sink, repeating in a
cycle
convection ​in the​ asthenosphere ​is what moves Earth’s ​plates
Rock cycle​ the processes by which rocks are constantly being recycled and changed into different kinds of
rocks
minerals​ naturally occurring, usually inorganic (fancy word which means not from living things), solids
consisting of a single element or compound that has a definite chemical composition and internal
arrangement of atoms. Minerals are pure substances - they have an EXACT chemical recipe, or formula.
Quartz​ is an example of a mineral - there is more oxygen in the earth’s crust than in the atmosphere
because of the mineral quartz, show below. The chemical formula is ​ SiO​2
crystal​ an orderly arrangement of atoms
or molecules. Crystal shape is a physical
property that helps to identify a
substance.
Quartz crystals​ are shown to the left
crystallize​ to form into crystals
Igneous:
* igneous rock ​a rock that forms when melted rock (magma or lava) hardens
* lava ​molten rock on the surface of Earth
vs.
* magma​ molten rock under the surface of Earth
* volcano ​an opening in Earth’s crust where lava, cinders, ash, and gases come to the surface
dormant​ in terms of volcanoes, a volcano that is not presently erupting but is likely to in the future
extinct​ in terms of volcanoes, a volcano that is not expected to erupt again
Igneous Rock Examples:
granite​ an igneous rock made of mostly quartz, visible as white crystals and feldspar, visible as little black
specks
obsidian​ is called volcanic glass because it is a rapidly cooling volcanic rock, shown below
Metamorphic:
* metamorphic rock​ a rock that has changed from ANOTHER ROCK because of heat, pressure, or a
chemical reaction - think of it as having a parent rock
Examples:
marble ​a rock that derives from limestone as a result of pressure, temperature, and time
gneiss​ a coarse-grained rock that has been subjected to extreme heat and pressure. The source rock is
often ​granite​, but it can also be from a ​sedimentary​ rock or another ​metamorphic​ rock.
schist​ a highly ​metamorphosed rock​ that can come from different source rocks, including ​slate
slate​ a ​metamorphic rock​ that forms when heat and pressure are applied to ​shale​. ​Slate​ looks very
similar to ​shale​, but slate is much harder because of the compression.
Sedimentary:
* sedimentary rock ​a rock that forms when layers of sediments get stuck together
* sediments ​particles of earth materials that are carried along by wind or water
* weathering ​the process by which larger rocks crack and break apart over time to form smaller rocks
* erosion ​the carrying away of weathered earth materials by water, wind, or ice
* deposition​ the settling of sediments
sand ​is​ ​rocks that are smaller than gravel but bigger than silt
sandstone ​a sedimentary rock made of sand particles stuck together
shale ​a ​sedimentary rock​ made of clay or silt
silt ​rocks that are smaller than sand but bigger than clay
limestone​ a ​sedimentary rock​ made mostly of calcite from deposits of ocean animal shells
Plate Boundaries:
plate boundaries ​the edge of a tectonic plate where earthquakes, volcanoes, and other tectonic activity
takes place because of the motions of the plates
plate ​a huge, irregularly shaped slab of the Earth’s lithosphere that fits together with all the other slabs to
form the surface of the Earth
plate tectonics​ a theory that says Earth’s outer layers are made of moving plates
tectonic​ the movement of Earth’s crust
tectonic plate ​sections of the lithosphere that move on top of the fluid asthenosphere; composed of Earth’s
crust and the hard top layer of the mantle
convergent boundary​ a boundary where plates move toward each other
hotspot​ a volcanic area that forms as a tectonic plate moves over a place heated from deep within Earth
subduction​ when one tectonic plate slides under another
subduction zone​ a place along a convergent boundary where one plate moves under another plate
divergent boundary ​a boundary where plates move away from each other
transform ​a fault where two plates slide past each other
transform boundary ​a boundary where plates move past one another
earthquake​ when the ground shakes or moves suddenly due to the release of built up stress convection
within the Earth’s crust or upper mantle; occurs along plate boundaries
uplift​ when sections of Earth’s crust rise as tectonic plates move
seismology​ the study of earthquakes
fault​ a break in the earth’s crust either within a plate or between plates
folding​ the deformation of rock layers in Earth’s crust as tectonic plates move
hotspot​ a volcanic area that forms as a tectonic plate moves over a place heated from deep within Earth
Landforms:
terrain​ the physical features of land
basin​ a large low area where sediments have been deposited
plateau​ a large area of flat-lying sedimentary rock that has been lifted high above its original elevation
terminal moraine​ an area of glacial sediment that forms at the farthest reaching point of a glacier
continental shelf​ a relatively shallow area of the ocean, usually less than 200 meters deep, that surrounds
a continent; the flooded part of a continent
trench ​the deep area where oceanic plates are converging and sinking
dome​ formed when magma pushes up from below Earth’s surface but doesn’t erupt. The rocks above are
uplifted and the cooling magma forms an igneous core beneath
talus​ jagged rocks found at the base of cliffs
groundwater​ water that has soaked into the ground and fills up spaces between rocks or deposited
materials
Lab Vocab:
carbonate​ a substance made of carbon and oxygen
Extra Vocab:
bedrock​ the rock that forms Earth’s crust
elevation​ the vertical distance of the land’s surface above sea level