How can we help?

You can also find more resources in our Help Center.

62 terms

Unit: Land Beneath Our Feet - Rocks, Weathering and Erosion, Soil and Soil Stewardship, Earthquakes and Volcanoes, Earth's Layers Subunit, Continental Drift Vocabulary

STUDY
PLAY
Sedimentary
A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together
Metamorphic
A type of rock that forms from an existing rock that is changed by heat and pressure.
Igneous
A type of rock that forms from the cooling of molten rock at or below the surface.
Extrusive
Igneous rock that forms from lava on earth's surface
fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface
Intrusive
a type of ingneous rock that generally contains large crystals and forms when magma cools slowly beneath Earth's surface.
Compaction
the process by which sediments are pressed together under their own weight
Deposition
Process in which sediment is laid down in new locations.
Cementation
The process by which dissolved minerals crystallize and glue particles of sediment together into one mass
Erosion
Processes by which rock, sand, and soil are broken down and carried away
Mechanical weathering
The type of weathering in which rock is physically broken into smaller pieces
Chemical weathering
The process that breaks down rock through chemical changes
rock cycle
a series of processes on the surface and inside earth that slowly changes rock from one kind to another
parent rock
a rock formation that is the source of soil
soil conservation
a method to maintain the fertility of the soil by protecting the soil from erosion and nutrient loss
topsoil
A upper layer of soil consisting of rock fragments, organisms, nutrients, water, air, and decaying matter.
subsoil
The layer of soil below topsoil that has less plant and animal matter than topsoil and contains mostly clay and other minerals.
humus
material formed from decaying leaves and other organic matter
decomposer
An organism that breaks down wastes and dead organisms
soil texture
The mixture of sizes of its particles and the proportion of different sizes
bedrock
solid layer of rock beneath the soil
sand
the coarsest soil, with particles 0.0-,2.0 mm in diameter.
silt
medium-size soil particles (0.002 - 0.05 mm in diameter)
clay
smallest soil particles, less than 0.002 mm in diameter
Tectonic Plates
An irregular section of the lithosphere that floats on the earth's mantle
Magma
Molten rock beneath the earth's surface
Primary waves
A seismic wave that travels the fastest, back-and-forth waves, move through solids, liquids, and gases
Secondary waves
A seismic wave that causes particals of rock to move in side-to-side directions
Surface waves
Seismic waves that reach and travel along the earths surface
Cinder cone volcano
small volcanic cones made almost entirely of pyroclastic material with moderately explosive eruptions
Composite volcano
a large, cone-shaped volcanic mountain; the cone shape is the result of repeated eruptions of ash and lava
lava
liquid magma that reaches the surface
Pyroclastic flow
the flow of ash, cinders, bombs, and gases down the side of a volcano during an explosive eruption
Shield volcano
a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions
Epicenter
Point on Earth's surface directly above an earthquake's focus
Focus
Point at the depth where the rocks ruptured to produce earthquakes; place where quake waves originate
matter
Anything that has mass and occupies space
mass
Amount of matter in an object
volume
Amount of space occupied by an object
density
Mass / Volume
crust
The layer of rock that forms Earth's outer surface
mantle
The layer of hot, solid material between Earth's crust and core.
inner core
A dense sphere of solid iron and nickel at the center of Earth
outer core
A layer of molten iron and nickel that surrounds the inner core of Earth
lithosphere
The rigid outer part of the earth, consisting of the crust and upper mantle.
asthenosphere
The soft layer of the mantle on which the lithosphere floats.
tectonic plates
An irregular section of the lithosphere that floats on the earth's mantle
Pangea
A supercontinent containing all of Earth's land that existed about 225 million years ago.
Convection Current
when the hot, soft rock on the asthenosphere rises, cools and then sinks in a continuous motion
Pangaea
the supercontinent hypothesized by Alfred Wegener
Plate Tectonics
Theory that the earth's surface (lithosphere) is broken into huge moving plates that move
Continental Drift
Alfred Wegener's hypothesis that continents were joined together and have broken and drifted apart
Rift Valley
place where molten rock rises to the Earth's surface creating new crust
Plate Boundary
location where the edges of two plates meet
Mid Ocean Ridges
huge underwater mountain ranges
Hot Spot
place where the mantle rises to the surface, often in the middle of plates, forming volcanoes
subduction
when two plates collide and one is pushed below the other
Divergent Boundary
boundary where two plates move apart
Convergent Boundary
boundary where two plates push together
Transform Boundary
boundary where two plates scrape together
Fossil Evidence of Continental Drift
fossils of an ancient reptile was found in South America and Western Africa
Climate Evidence of Continental Drift
Fossils of tropical plants found on the shores of Greenland which is now in the Arctic Circle
Geology Evidence of Continental Drift
Rock found in Brazil matches rock in west Africa, and stone in the Appalachian Mountains are exactly like those in Scotland's Highlands