APES Unit 4 Plate Tectonics & Soil

lithosphere

the outermost layer of Earth, including the solid upper mantle & crust

asthenosphere

the layer of the Earth located in the outer part of the mantle, composed of semi-molten rock

mantle

the layer of Earth above the core, containing magma, the asthenosphere, and the solid upper mantle

core

the innermost zone of Earth’s interior, composed of mostly iron & nickel, include a liquid outer layer & a solid inner layer

Earthquake

a sudden movement of Earth’s crust caused by the release of potential energy from the movement of tectonic plates

Epicenter

exact point on the surface of Earth directly above the location where rock ruptures

Richter scale

how earthquakes are measured

Volcano

a vent in Earth’s surface that emits ash, gases, and molten lava

hot spots

places where molten material from the mantle reaches lithosphere

• as a plate moves over a geological hotspot → heat from the rising mantle plumes melt crust → volcano

Tsunami

a series of waves in the ocean caused by seismic activity in the ocean or an undersea volcano that causes a massive displacement of water

Divergent Plate Boundaries

• plates move apart

• an area elow the ocean where tectonic plates move away from each other

seafloor spreading

rising magma forms new oceanic crust on the seafloor as the boundaries between those plates

• divergent

rift zones/valleys

divergent

between continental plates 

convergent plate boundaries

• plates come together

• when one plate moves toward another plate & collides

subduction

convergent

an oceanic plate meets a continental plate, the edge of the oceanic plate moves downward beneath the continental plate & is pushed toward the center of the Earth 

results: volcanic activity increases

collision

convergent

two continental plates collide

results in mountain range 

island arcs

convergent

areas where subduction occurs chains of islands are formed by volcano bc 2 oceanic tectonic plates coming together & experiencing subduction

transform plate boundaries

• plates slide past each other

fault

transform

• see a fracture in the rock caused by movement in Earth’s crust

• occurs b/c rough edges of the two plates are building up energy as they try to slide past e/o & then release a great deal of energy when they finally experience movemen

igneous 

rock formed directly from magma

classified by their chemical composition as basaltic or granitic 

sedimentary

form when sediments such as muds, sands, gravels are compressed by overlying sediments

holds the fossil record that provides a window into our past

metaphoric

when sedimentary rocks, igneous rocks, or other metaphoric rocks are subjected to high temperatures & pressures

pressures cause physical & chemical changes on the rock

physical weathering

mechanical breakdown of rocks & minerals

caused by water, wind, variations in temp.

biological agents

exposes more surface area & makes rocks even more vulnerable to further degradation

chemical weathering

the breakdown of rocks & minerals by chemical reactions, the dissolving of chemicals elements from rocks, or both

releases essential nutrients from rocks 

erosion

physical removal of rock fragments from a landscape/ecosystem

2 mechanism

1. wind, water, ice move soil & other materials down a slope under the force of gravity

2. living organisms

human land contributes to the rate

benefits of soil

medium for plant growth

breaks down organic material & recycles nutrients

filters water

habitat for a variety of organisms

soil horizons

a horizontal layer in a soil defined by distinctive physical features such as color & texture

O horizon

organic matter in various stages of decomposition

A horizon

zone of overlying organic material mixed with underlying mineral material

topsoil

E horizon

zone of leaching of metals & nutrients, occurs in some soils beneath either the O horizon/A horizon

B horizon

subsoil

zone of accumulation of metals & nutrients

C horizon

subsoil

least-weathered portion of the soil profile, similar to the parent material 

R horizon

bed rock

unweathered parent rock

porosity

the size of the air spaces between particles

sand higher than clay

water-holding capacity

the amount of water a soil can hold against the draining force of gravity → depends on the texture

soils with high water holding capacity have low water permeability 

permeability

ability of water to move through the soil

cation exchange capacity (CEC)

the ability of a particular soil to absorb & release cations

base saturation

the proportion of soil bases to soil acids, expressed as percentage