chapter 14: Geology

Question 1

earth core

Answer 1

interior composed of dense, intensely hot metal, mostly iron. generates magnetic field enveloping the earth

Question 2

earth mantle

Answer 2

hot, pliable layer surrounding the core, less dense than the core

Question 3

earth crust

Answer 3

cool, lightweight, brittle, outermost layer; floats on top of the mantle

Question 4

tectonic processes

Answer 4

upper layer of mantle contains convection currents that break overlying crust into tectonic plates that slide slowly across earth’s surface

Question 5

when tectonic plates slide

Answer 5

ocean basins form where continents crack and pull apart, magma (molten rock) forced up through the cracks form new oceanic crust piles up underwater mid-ocean ridges

Question 6

earthquakes

Answer 6

caused by grinding and jerking as plates slide past each other

Question 7

subduction zones

Answer 7

markedby deep ocean trenches

Question 8

mineral

Answer 8

naturally occurring inorganic, solid element of compound with definite chemical composition and regular internal crystal structure

Question 9

rock

Answer 9

solid, cohesive, aggregate of one or more minerals, characteristic mixture of minerals, grain sizes, and ways in which the grains are mixed and held together

Question 10

rock cycle

Answer 10

cycle of creation, destruction and metamorphosis

Question 11

major rock classifications

Answer 11

igneous, sedimentary, metamorphic

Question 12

igneous rocks

Answer 12

most common type in earth’s crust, solidified from magma extruded onto surface from volcanic vents, cooling magma creates basalt, granite

Question 13

metamorphic rock

Answer 13

preexisting rocks modified by heat, pressure, and chemical agents, chemical reactions alter composition and structure as they are metamorphosed, marble, slate

Question 14

mechanical weathering

Answer 14

physical break-up of rocks into smaller particles without a change in chemical composition

Question 15

chemical weathering

Answer 15

selective removal or alteration of specific components that leads to weakening and disintegration of rock, oxidation and hydrolysis

Question 16

sedimentation

Answer 16

deposition of particles of rock transported by wind, water, ice and gravity until they come to rest in a new location

Question 17

sedimentary rock

Answer 17

deposited materials that remain in place long enough or covered with enough material for compaction, sandstone and shale, shaped by erosion, can be formed from crystals

Question 18

geomorphology

Answer 18

study of processes that shape the earth’s surface and the structures they create, humans shape more than other processes minus plate tectonics

Question 19

economic mineralogy

Answer 19

study of minerals that are valuable for manufacturing

Question 20

metals

Answer 20

consumed in greatest quantities by world industry, iron most often

Question 21

gemstones and precious metals

Answer 21

monetary value bankrolls despots, criminal gangs, terrorism, inhumane labor conditions

Question 22

sand and gravel

Answer 22

greatest volume and dollar value, brick and concrete, sandblasting, glass production

Question 23

extraction

Answer 23

disturbance or removal of land surface, 80,000 metric tons of dust, toxic air pollutants, chemical and sediment runoff, contaminated freshwater with acid, arsenic, heavy metal

Question 24

placer mining

Answer 24

hydraulically washing out metals deposited in stream bed gravel by using water cannons to blast away stream beds

Question 25

underground mining

Answer 25

tunneling into mineral seams, dangerous, natural gas explosions, collapse of tunnel, water seeping into mines dissolves toxic minerals contaminating water, fires burn for years

Question 26

open pit or strip mining

Answer 26

50% US coal, creates huge holes with fill with contaminated groundwater, surface material is left long ridges called spoil banks

Question 27

surface mining control and reclamation act

Answer 27

requires better restoration of strip-mined lands, difficult and expensive, more that $10,000/hectare

Question 28

mountaintop removal

Answer 28

ridge tops removed to access a coal bed, material from top of mountain is crushed and dumped into river valleys burying streams in toxic substances

Question 29

smelting

Answer 29

roasting ore to release metals, major source of air pollution

Question 30

heap-leach extraction

Answer 30

crushed ore piled in large heaps and sprayed with a dilute alkaline cyanide solution which percolates through pile to dissolve the gold

Question 31

recycling

Answer 31

aluminum must be extracted from bauxite by electrolysis which is energy expensive, commonly recycled plantinum, gold, silver, copper, lead, iron, steel

Question 32

reduce metal consumption by...

Answer 32

using new materials or new techniques like, metal pipes replaced by plastic pipes, metal wires replaced by fiber optics, steel replaced by polymers, aluminum, ceramics, and new alloys

Question 33

geologic hazards

Answer 33

asteroid impact led to extinction of dinosaurs, floods take the greatest number of lives, wind causes most property damage, earthquakes

Question 34

gradual movement

Answer 34

called creep or seismic slip, when friction prevents creep, stress builds up until eventually released with a sudden jerk

Question 35

epicenter

Answer 35

point at which first movement occurs in an earthquake

Question 36

earthquakes cause more damage...

Answer 36

when construction is poor

Question 37

tsunami

Answer 37

generated by earthquakes, tidal wave

Question 38

what are the sources of most of the earths crust?

Answer 38

volcanoes and undersea magma vents

Question 39

volcanoes

Answer 39

fertile soils are weathered volcanic material, 500 million people live in danger zones

Question 40

nuees ardentes

Answer 40

buring cloud, deadly clouds of hot gas and ash like those that destroyed pompeii, volcanic dust and sulfur emissions reduce sunlight and temperature around globe

Question 41

landslides

Answer 41

example of mass wasting, geologic material are moved downslope from one place to another, speeds vary

Question 42

damage caused by landslides

Answer 42

road construction, forest clearing, cultivation, and building on steep, unstable slopes increase the frequency