Chapter 14 Flashcards
Earth is a layered sphere. What are the 3 major layers, and their descriptions?
1.Core - interior composed of dense, intensely hot metal, mostly iron. Generates magnetic field
enveloping the earth.
- Mantle - hot, pliable layer surrounding the core. Less dense than core.
- Crust - cool, lightweight, brittle outermost layer. Floats on top of mantle.
When continental plates and oceanic plates collide, which one subducted down, and where
does it enter to be melted down?
The oceanic plate will subduct down into the mantle where it melts.
Define minerals, rock and rock cycle.
Mineral is a naturally occurring, inorganic, solid element or compound with a definite chemical
composition and regular internal crystal structure.
Rock is a solid, cohesive, aggregate of one or more minerals. Each rock has a characteristic
mixture of minerals, grain sizes, and ways in which the grains are mixed and held together.
Rock Cycle - cycle of creation, destruction, and metamorphosis
Please list the three major rocks as classified.
- Igneous
- Sedimentary
- Metamorphic
Describe different types of weathering. Also describe sedimentation.
Mechanical weathering - physical break-up of rocks into smaller particles without a change in
chemical composition.
Chemical weathering - selective removal or alteration of specific components that leads to
weakening and disintegration of rock(including oxidation and hydrolysis processes).
Sedimentation - deposition of particles of rock transported by wind, water, ice, and
gravity until they come to rest in a new location. Also can be formed from crystals that
precipitate out of, or grow from, a solution. Example: halite
Please rank the following 5 metals from the greatest quantity to the smallest quantity as
consumed by the world industry:
Aluminum, copper and chromium, iron, manganese, and
nickel .
Iron : (740 million) Aluminum: (40 million) Manganese: (22.4 million) Copper and Chromium: (8 million ea) Nickel: (0.7 million)
What are the environmental impact of mineral extraction?
Disturbance or removal of land surface. 80,000 metric tons of dust. Produces more than 100
Toxic air pollutants, Chemical and sediment runoff. When sulfide ores are exposed to air and
water, they produce sulfuric acid. Vast quantities of ore must be crushed and washed to obtain
small quantities of metal; enormous amounts of freshwater are thereby contaminated with acid,
arsenic, & heavy metal
There are different types of mineral mining. Please explain placer mining, underground
mining, open pit or strip mining, as well as their negative attributes. Which one is the most
dangerous to humans and why?
1.Placer Mining - hydraulically washing out metals deposited in streambed gravel by using water
cannons to blast away stream beds. Destroys streambeds and fills water with suspended solids.
2.Underground mining - tunneling into mineral seams is very dangerous. Tunnels can collapse.
Natural gas explosions. Water seeping into mine shafts dissolves toxic minerals and
contaminates groundwater. Fires in mines which burn for years
3.Open pit or strip mining. 50% of U.S. coal is strip mined. Creates huge holes in the earth
which fill with contaminated groundwater. Surface material is left in long ridges called spoil
banks, because these do not contain topsoil, there often is no vegetation for many years.
Underground Mining is the most dangerous because Tunnels can collapse. Natural gas
explosions. Water seeping into mine shafts dissolves toxic minerals and contaminates
groundwater. Fires in mines which burn for years
What was the purpose of Surface Mining Control and Reclamation Act of 1977?
Requires better restoration of strip-mined lands, especially if land is classed as prime farmland
Metals are extracted from ___ by heating or treatment with chemical solvents.
Ores
What is an ore?
An ore is an occurrence of rock or sediment that contains sufficient minerals with
economically important elements, typically metals, that can be economically extracted
from the deposit
Please explain smelting and Heap-Leach Extraction.
Smelting - roasting ore to release metals. Major source of air pollution
Heap-Leach Extraction - crushed ore piled in large heaps and sprayed with a dilute alkaline
cyanide solution which percolates through the pile to dissolve the gold. Effluent left behind in
ponds can leak into surface water or groundwater.
What is earthquake epicenter? Tsunami?
Point at which first movement occurs is called the epicenter
Tsunami is a series of waves in a water body caused by the displacement of a large
volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions (including detonations, landslides, glacier calvings, meteorite impacts and other disturbances) above or below water all have the potential
to generate a tsunami.
What are the negative impact of volcanic eruption?
Mudslides often accompany eruptions. Volcanic dust and sulfur emissions reduce sunlight and
temperature around the globe.
What is landslide/mass wasting?
Landslides are examples of mass wasting, in which geologic materials are moved downslope from one place to another
