Chapter 14: Geology and Earth Resources Flashcards
Core
The dense, intensely hot mass of molten metal, mostly iron and nickle, thousands of kilometers in diameter at the earth’s center
Mantle
A hot, pliable layer of rock that surrounds the earth’s core and underlies the cool, outer crust
Crust
The cool, lightweight, outermost layer of the earth’s surface that floats o the soft, pliable underlying layers; similar to the “skin” on a bowl of warm pudding
What are the 3 most common elements in the Earth?
Iron, Oxygen, and Silicon
What are the 3 most common elements in the crust?
Oxygen(45.2%), Silicon(27.2%), and Aluminum(8.2%)
How old is the crust?
Less than 200 million years
Tectonic Plates
Huge blocks of the earth’s crust that slide around slowly, pulling apart to open new ocean basins or crashing ponderously into each other to create new, larger landmasses
Magma
Molten rock from deep in the earth’s interior; called lava when it spews from volcanic vents
Mid-Ocean Ridges
Mountain ranges on the ocean floor created where molten magma is forced up through the cracks in the planet’s crust
What are earthquakes caused by?
The grinding and jerking of plates as they slide past each other
When will Los Angeles pass San Francisco (predicted)?
In 30 million years
Subduction
The process by which one tectonic plate is pushed down below another as plates crash into each other
Mineral
A naturally occurring, inorganic, solid element or compound with a definite chemical composition and a regular internal crystal structure
Rock
A solid, cohesive, aggregate of one or more minerals
Rock Cycle
The process whereby rocks are broken down by chemical and physical forces; sediments are moved by wind, water, and gravity, sedimented and reformed into rock, and then crushed, folded, melted, and recrystallized into new forms
Igneous Rocks
Crystalline minerals solidified from molten magma from deep int eh earth’s interior; basalt, rhyolite, adesite, lava, and granite are examples
Metamorphic Rocks
Igneous and sedimentary rocks modified by heat, pressure, and chemical reactions; marble, quartzite, and slate.
Weathering
Changes in rocks brought about by exposure to air, water, changing temperatures, and reactive chemical agents
Mechanical Weathering
The physical breakup of rocks into smaller particles without a change in chemical composition of the constituent minerals
Chemical Weathering
The selective removal or alteration of specific components that leads to weakening and desintegration of rock
Oxidation
Combination of oxygen with an element to form and oxide or hydroxide mineral
Hydrolysis
Hydrogen atoms from water molecules combine with other chemicals to form acids
Sedimentation
The deposition of organic materials or minerals by chemical, physical, or biological processes
Lithosphere
Earth’s crust made up of a layer of rock
The lithosphere is broken into pieces called what?
Plates
What does the lithosphere rest on?
Partially molten rock material called the asthenosphere
Theory of Plate Tectonics
Explains the method by which large crustal plates can move
How do the plates on the Earth’s surface move?
Convection of heat in the asthenosphere
How is the direction of the tectonic plates’ movement determined?
The direction of the convection of heat
Convergent Plate Boundary
Plates are pushing into each other
Ex: subduction zones and transform faults
Divergent Plate Boundary
Plates are pulling apart from each other
Ex: mid-ocean ridge, Red Sea, African Rift Valley
Hot Spot
Hole in the midst of a plate where magma may rise.
Ex: Hawaii
What are the three types of plate boundaries?
Convergent, divergent, and hot spot
Pangea
Supercontinent where all plates were joined
Laurasia and Gondwanaland
Resulted from the separation of Pangaea
Laurasia
Northern mass
Gondwanaland
Southern mass
How many continents are there?
7 continents
What are the 7 continents?
North America, South America, Europe, Australia, Antarctica, Africa, and Asia
Eras
Cenozoic, Mesozoic, Paleozoic, Precambrian Time
Periods
Increments of eras based on dominant species and extinctions of life forms
Epochs
Divided periods of the Cenozoic (current era)
Rock Cycle
- Magma cools to form igneous rock
- Igneous rock can be weathered into sediment to form sedimentary rock or reheated to form metamorphic rock.
- Sediments can be consolidated to form sedimentary rock, then heated to become metamorphic rock
Intrusive Igneous Rocks
Cool underground from magma
Ex. Granite
Extrusive Igneous Rocks
Cool above ground from lava
Ex. Obsidian
Foliated Metamorphic Rocks
Show bands or layers
Ex. Gneiss (Granite)
Non-Foliated Metamorphic Rocks
Show no bands or layers
Ex. Marble (Limestone)
Clastic Sedimentary Rocks
Sediments of varying sizes that have been compacted/cemented together
Ex. Conglomerate
Non-Clastic Sedimentary Rocks
Sediments form out of solution or from living materials
Ex. Coal
How much rock is estimated that humans move a year?
30-35 gigatons of rock material per year worldwide
1 gigaton = 1 billion tons
What human activities move rock?
Building excavations, road construction, and mineral production
Economic Geology
Study of minerals that are valuable for manufacturing and commerce
Most are metal-bearing ores
What are the top 5 metals consumed in the U.S?
Aluminum, Chromium, Copper, Iron, and Lead
What are the top 5 non-metals consumed in the U.S?
Gravel, clay, sand, salt, and graphite
What are the top 3 metals used worldwide?
Iron, Aluminum, and Manganese
What countries/places are the top 3 consumers of the metals?
U.S.A
Japan
Europe
MIning
Minerals and fossil fuels are mined from the earth’s crust.
Methods vary due to topography, safety and economics (cost)
Surface or Strip Mining
Removes deposits that lie in horizontal beds
Land is first clear-cut, then land over the deposit is removed with explosives and heavy equipment. Then, the deposit is removed. (Even when reclaimed, there is long-term environmental damage.)
Mountaintop Removal
Type of surface mining. Technique for coal mining. Explosives are used to remove the top of a mountain,
excessive land materials are moved to the
valley and sometimes fill rivers/streams
Open-Pit MIning
A huge hole is dug in the ground using explosives and heavy equipment, then the desired deposit is removed
Abandoned pits often fill with water which becomes acidic
from mining waste
Subsurface Mining
Deep mine shafts are dug with branching underground tunnels
There is less habitat destruction on the surface but these mines are dangerous. Cave-ins, toxic fume build-up,
dust, and flooding can kill miners
Drilling
Used primarily for liquid and gas extraction. Drilling pads/platforms are needed and pipelines are often constructed
Danger in high pressures associated with drilling. Off-shore drilling can result in spills/leaks
Surface Mining Control and Reclamation Act (1977)
Regulates U.S. coal mining activities and
requires reclaiming (returning it to original state)
of land after use
Federal Mine Safety and Health Act
Sets forth federal health and safety regulations for both coal
and non-coal mining operations in the U.S
The General Mining Law of 1872
Encourages exploration and mining of mineral resources.
Corporations can buy large tracts of land cheap
Critics say its not fair for corporations to not pay
royalties or adequately clean up
Energy Policy Act
Provides incentives to corporations for developing energy resources including fossil fuels, nuclear, and alternative
energy resources
What are 2 environmental costs of mining?
*Mining usually begins with clear-cutting forests
and removing the native vegetation. Soil horizons
are destroyed; Mining produces the most
hazardous emissions of any activity
*Streams and rivers are polluted with silt and sand,
sometimes completely clogged or buried. Toxic
chemicals used in mining can leach into
waterways
In the U.S., what percentage of all solid waste comes from mining operations?
75%
Acid Mining Drainage
Sulfur compounds in mine waste form sulfuric acid solution creating acidic runoff
Ore
Rock material containing a resource that can be mined for a profit. High-grade ores are desirable. Low-grade ores have small amounts of resource or are too expensive to mine
Mineral resources are classified as non-
renewable
Smelting
The heating of ores to remove metals produces air pollution
The pollution contains
heavy metals, particulate matter, and sulfur
dioxide which can transform into acid rain
Cyanide Solution Mining (Heap-Leach Extraction)
Practice of spraying cyanide solutions on piles of crushed ore to dissolve the rock material and leave metal (gold) behind
This leaves cyanide-laced residue that can leach into
groundwater or runoff to poison local waterways
Reserve
A location from a mineral can be
extracted in an economically viable manner
Ex. NW U.S. silver reserve
Earthquakes
Are sudden movements in the earth’s crust that occur along faults (breaks in rock material that move or shift)
Usually occur without warming; Death tolls are highest in places with poor building construction (Haiti)
Tsunamis
Occur when earthquakes take place on the ocean floor sending a column of water into motion
Volcanoes
Are mountain structures with tectonic activity. They have at some point in their history had a magma chamber and vent
capable of extruding hot, molten rock (gas, ash, and lava)
Nuees Ardentes
(French for glowing clouds) are deadly mixtures of hot gas and ash
The famous eruption of Mt. Vesuvius produced this event
Mass Wasting
Gravity acts on crustal material to produce mass movement
Fast – rockslide, mudslide, avalanche
(landslides)
Slow – creep, slump
Cost – over 1 billion dollars in property
damage occurs each year in the U.S. due to
landslides. California is an area with the
highest costs because people build expensive
homes on steep hills of unconsolidated soil.
What is the rule about the Richter Scale?
For every unit increase in the Richter scale, ground displacement increases by a factor of 10, while energy increases by a factor of 30.
What were the top five worst natural disasters caused by?
Floods
Where were the top five worst natural disasters?
In China
What are the top 5 world’s worst polluted places?
Chernobyl, Ukraine; Nuclear power plant Dzerzhinsk, Russia; Weapons production Haina, Dominican Republic; Lead smelter Kabwe, Zambia; Lead mine and smelter La Oroya, Peru; Mine and smelter
What magnitude on the Richter Scale defines each type of earthquake?
2-2.9; Unnoticeable 3-3.9; Smallest felt 4-4.9; Minor earthquake 5-5.9; Damaging earthquake 6-6.9; Destructive earthquake 7-7.9; Major earthquake >8; Great earthquake
