APES CHAPTER 8

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mantle

the layer of the earth between the crust and the core

magma

molten rock

asthenosphere

located in the outer part of the mantle and is composed of semi-molten, ductile rock

lithosphere

a 60 mile think layer that includes the solid upper mantle as well as the crust

crust

the outermost layer of the lithosphere

hot spots

places where molten material from the mantle reaches the lithosphere

plate tectonics

Earth's lithosphere is divided into plates, most of which are in constant motion

tectonic cycle

the sum of the processes that build up and break down the lithosphere

subduction

the process of one plate passing under another

volcano

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

divergent plate boundaries

when oceanic plates move apart as if on a giant conveyor belt

seafloor spreading

when the magma rises up and outward, forming new rock. This process brings important elements such as copper & lead to the surface of the Earth

convergent plate boundaries

when plates move toward one another and collide, and the lighter layer goes on top of the heavier, subducted layer

transform boundary

a plate boundary where two plates move/slide past each other in opposite directions

fault

a fracture in rock across which there is movement

fault zones

large expanses of rock where movement has occurred

earthquakes

sudden movements of Earth's crust followed by a series of shocks

epicenter

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

richter scale

a measure of the largest ground movement that occurs during an earthquake

minerals

solid chemical substances with uniform structures that form under specific temperatures and pressures They are usually compounds

igneous rocks

rocks that form directly from magma. They are classified as basaltic or granitic [i.e granite, basalt]

sedimentary rocks

rocks that form when sediments like mud, sand, or gravel are compressed by overlying sediments. It forms over long periods of time. This layer often holds fossils [i.e. sandstone, limestone]

metamorphic rocks

rocks that form when sedimentary rocks, igneous rocks, or other metamorphic rocks are subjected to high temperatures and pressures [i.e. marble, quartzite]

physical weathering

Weathering in which solid rock is fragmented by mechanical processes that do not change its chemical composition.

chemical weathering

The process that breaks down rock through chemical changes

acid rain

rain containing acids that form in the atmosphere when industrial gas emissions (especially sulfur dioxide and nitrogen oxides) combine with water

erosion

the physical removal of rock fragments from a landscape or ecosystem

deposition

the accumulation or depositing if eroded material such as sediment, rock fragments, or soil

soil

a mix of geologic and organic compounds. Often called "Earth's dynamic membrane"

parent material

the rock material underlying soil from which its inorganic components are derived

horizons

soil layers, a specific layer or stratum of soil or subsoil in a vertical cross section of land

O horizon

the top-most soil layer that has organic matter in various stages of decomposition

A horizon

the topsoil layer that is a zone of overlying organic material and underlying mineral material

B Horizon

a zone of accumulation of metals and nutrients, commonly known as subsoil

C horizon

the least weathered soil horizon that is similar to the parent material

cation exchange capacity

the ability of a particular soil to absorb and release cations. This is sometimes referred to as the nutrient holding capacity

base saturation

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

soil degradation

the loss of some or all of the ability of soils to support plant growth

ores

concentrated accumulations of minerals from which economically valuable materials can be extracted

metals

elements with properties that allow them to conduct electricity and heat energy and perform other important functions

reserve

the known quantity of a resource that can be economically recovered

strip mining

the removal of "strips" of soil and rock to expose ore and is used when the desired ore is relatively close to Earth's surface and runs parallel to it

tailings

mining spoils

open pit mining

the creation of a large pit or hole in the ground that is visible from Earth's surface, and is used when the resource is close to the surface but extends beneath the surface both horizontally and vertically

mountaintop removal

when miners remove the entire top of a mountain with explosives, this is really bad for the Earth

placer mining

the process of looking for metals and precious stones in river sediments

subsurface mining

begins with a horizontal tunnel dug into the side of a mountain or other feature containing the resource. From here, vertical shafts are drilled and elevators are used to bring miners down to the resource and back to the surface