apes 8

when was the earth formed

4\.6 billion years

core

¨the innermost zone of the planet made of nickel and iron. Solid inner core and liquid core

mantle

¨above the core containing magma

crust

the outermost layer of the planet

asthenosphere

¨the outer part of the mantle, composed of semi-molten rock

Lithosphere

the brittle outermost layer of the planet that is approximately 100 km thick. It includes the solid upper mantle and the crust

hotspots

places where molten material from the mantle reach the lithosphere

what happens at hotspots

¨heat causes plumes of hot magma to well upward from the mantle.

Plate tectonics-

the theory that states that Earth’s lithosphere is divided into plates, most of which are in constant motion

Volcanoes-

¨as a plate moves over a hot spot, rising magma forms a volcano

Divergent plate boundaries

¨when plates move apart from one another (soil)

Convergent plate boundaries-

¨when plates move toward one another and collide (earthquakes)

Transform fault boundaries-

when plates move sideways past each other (mostly earthquakes)

Faults-

¨a fracture in rock across which there is movement

Earthquakes-

occur when the rocks of the lithosphere rupture unexpectedly along a fault

Fault zone-

¨large expanses of rock where movement has occurred

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. The scale increases by a factor of 10, so an earthquake of 7 is 10 times greater than an earthquake of 6

Rock cycle-

the constant formation and destruction of rock. 

Igneous rocks-

¨rocks (granite) that form directly from magma

Intrusive igneous-

¡form from within Earth as magma cools

Extrusive igneous-

from when magma cools above Earth. (ex. A volcano that ejects magma out will form this)

Sedimentary rocks-

¨form when sediment such as mud, sands (shale, limestone – high in calcium), or gravels are compressed by overlying sediments

Lithocation

forms the lithosphere

Metamorphic rocks-

form when sedimentary, igneous or other metamorphic rocks are subjected to high temperatures and pressures

Weathering-

when rocks are exposed to air, water, certain chemicals or biological agents that degrade the rock

Physical weathering-

the mechanical breakdown of rocks and minerals

Chemical weathering-

the breakdown of rocks and minerals by chemical reactions

farmers add what to decrease the acidity of fields

limestone

Erosion-

¨the physical removal of rock fragments from a landscape or ecosystem. Wind, water, ice transport and living organisms can erode materials

Deposition-

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

soil is a …… for plant growth

medium

soil is a …… for water

filter

soil is a …… for living organisms

habitat

soil is a ……. for pollutants

filter

Parent material-

what the soil is made from influences soil formation

¨e rock material from which soil is derived

Climate-

what type of climate influences soil formation

Topography-

the surface and slope can influence soil formation

Organisms-

Plants and animals can have an effect on soil formation

Time-

the amount of time a soil spend developing can determine soil properties

O horizon-

¨organic layer) composed of the leaves, needles, twigs and animal bodies on the surface

A horizon-

(topsoil) the zone of organic material and minerals mixed together

B horizon-

¨(subsoil) composed primarily of mineral material with very little organic matter

C horizon-

(parent material) the least weathered horizon and is similar to the parent material

Texture-

the percentage of sand, silt, and clay the soil contains

Porosity-

¨how quickly the soil drains (which depends on its texture)

Cation exchange capacity-

the ability of a soil to absorb and release cations, positively charged mineral ions

Soil bases-

calcium, magnesium, potassium, and sodium

Soil Acids-

aluminum and hydrogen

Base saturation-

the proportion of soil bases to soil acids

elemental composition of earth’s crust

oxygen- 46

silicon- 28

aluminum- 8

iron- 6

magnesium- 4

other- 2.4

calcium- 2.4

Reserves-

the known quantity of a resource that can be economically recovered.

Surface mining-

¨removing minerals that are close to Earth’s surface

Strip mining-

úremoving strips of soil and rock to expose one

Open pit mining-

úthe creation of a large pit or hole in the ground that is visible from the surface

Mountain top removal-

úremoving the entire top of a mountain with explosives

Placer mining-

looking for metals and stones in river sediments

Subsurface mining- 

mining for resources that are 100 m below Earth’s surface.

mining law

1872

surface mining control + reclamation act

1977