Chapter 16 Flashcards
Geology
study of the earth’s dynamic history. Geologists study and analyze rocks and the features and processes of the earth’s interior and surface.
Core
Inner zone of the earth. It consists of a solid inner core and liquid outer core.
Mantle
zone of the earth’s interior between its core and its crust.
Crust
solid outer zone of the earth. It consists of oceanic crus and continental crust.
Convection cells/currents
move large volumes of rock and heat in loops within the mantle like a giant conveyer belt.
mantle plumes
mantle rock flows slowly upward in a column, like smoke from a chimney on cold, calm morning.
tectonic plates
various-sized areas of the earth’s lithosphere that move slowly around with the mantle’s flowing asthenosphere. Most earthquakes and volcanoes occur around the boundaries of these plates.
lithosphere
outer shell of the earth, composed of the crust and the rigid, outermost part of the mantle outside the asthenosphere; material found in earth’s plates.
continental drift
throughout the earth’s history, continents have split and joined as plates have very slowly drifted thousands of kilometers back and forth across the planet’s surface.
divergent plate boundary
area where earth’s lithospheric plates move apart in opposite directions.
convergent plate boundary
area where earth’s lithospheric plates are pushed together.
transform fault
area where the earth’s lithospheric plates move in opposite but parallel directions along a fracture (fault) in the lithosphere.
erosion
process or group of processes by which loose or consolidated earth materials and dissolved, loosened, or worn away and removed from one place and deposited in another.
weathering
physical and chemical processes in which solid rock exposed at earth’s surface is changed to separate solid particles and dissolved material, which can then be moved to another place as sediment.
physical/mechanical weathering
a large rock mass is broken into smaller fragments.
frost wedging
water collects in pores and cracks of rock, expands upon freezing, and splits off pieces of the rock.
chemical weathering
one or more chemical reactions decompose a mass of rock.
biological weathering
the conversion of rock or minerals into smaller particles through the action of living.
earthquake
shaking of the ground resulting from the fracturing and displacement of rock, which produces a fault, or from subsequent movement along the fault.
richter scale
a measurement used by scientists to determine the magnitude of earthquakes.
aftershocks
gradually decrease in frequency over a period of up to several months.
foreshocks
from seconds to weeks before the main shock.
tsunamis
coastal areas can be severely damaged by earthquakes at sea that can generate huge water waves. aka tidal waves, have nothing to do with tides.
volcano
vent or fissure in the earth’s surface through which magma, liquid lava, and gases are released into the environment.
fissure
a central vent or long crack in the earth’s surface.
ejecta
debris ranging from large chunks of lava rock to ash that may be glowing hot.
mineral
any naturally occurring inorganic substance found in the earth’s crust as a crystalline solid.
rock
any material that makes up a large, natural, continuous part of the earth’s crust.
igneous rock
rock formed when molten rock material (magma) wells up from the earth’s interior, cools, and solidifies into rock masses.
sedimentary rock
rock that forms from the accumulated products of erosion and in some cases from the compacted shells, skeletons, and other remains of dead organisms.
metamorphic rock
rock produced when a preexisting rock is subjected to high temperatures (which may cause it to melt partially), high pressures, chemically active fluids, or a combination of these agents.
rock cycle
largest and slowest of the earth’s cycles, consisting of geologic, physical, and chemical processes that form and modify rocks and soil in the earth’s crust over millions of years.
nonrenewable mineral resource
a concentration of naturally occurring nonrenewable material in or on the earth’s crust that can be extracted and processed into useful materials at an affordable cost.
ore
part of a metal-yielding material that can be economically and legally extracted at a given time. An ore typically contains two parts: the ore mineral, which contains the desired metal, and waste mineral material (gangue).
identified resources
deposits of a particular mineral-bearing material of which the location, quantity, and quality are known or have been estimated from direct geological evidence and measurements.
reserves
resources that have been identified and fro which a usable mineral can be extracted profitably at present prices with current mining technology.
undiscovered resources
potential supplies of a particular mineral resource, believed to exist because of geologic knowledge and theory, although specific locations, quality, and amounts are unknown.
surface mining
removing soil, subsoil, and other strata and then extracting a mineral deposit found fairly close to the earth’s surface.
subsurface mining
extraction of a metal ore or fuel resource such as coal from a deep underground deposit.
overburden
layer of soil and rock overlaying a mineral deposit. Surface mining removes this layer.
spoils
unwanted rock and other waste materials produced when a material is removed from the earth’s surface or subsurface by mining, dredging, quarrying, and excavation.
open-pit mining
removing minerals such as gravel, sand, and metal ores by digging them out of the earth’s surface and leaving an open pit.
dredging
type of surface mining in which chain buckets and draglines scrape up sand, gravel, and other surface deposits covered with water. It is also used to remove sediment from streams and harbors to maintain shipping channels.
area strip mining
type of surface mining used where the terrain is flat. An earthmover strips away the overburden, and a power shovel digs a cut to remove the mineral deposit. After removal of the mineral, the trench is filled with overburden and a new cut is made parallel to the previous one. This process is repeated over the entire site.
contour strip mining
form of surface mining used on hilly or mountainous terrain. A power shovel cuts a series of terraces into the side of a hill. An earthmover removes the overburden, and a power shovel extracts the coal, with the overburden from each new terrace dumped onto the one below.
mountaintop removal
type of surface mining that uses explosives, massive shovels, and even larger machinery called draglines to remove the top of a mountain to expose seams of coal underneath a mountain.
Surface Mining Control and Reclamation Act of 1977
requires mining companies to restore most surface-mined land so it can be used for the same purpose as before it was mined.
Subsidence
slow or rapid sinking of part of the earth’s crust that is not slope-related.
acid mine drainage
when rainwater seeping through a mine or mine wastes carries sulfuric acid to nearby streams and groundwater.
gangue
one of the two components of ore, and it is the waste material.
tailings
removing the gangue from the ores produces piles of waste.
smelting
process in which a desired metal is separated from the other elements in an ore mineral.
depletion time
the time it takes to use a certain fraction, usually 80% of the known or estimated supply of a nonrenewable resource at an assumed rate of use. Finding and extracting the remaining 20% usually costs more than it is worth.
General Mining Law of 1872
was designed to encourage mineral exploration and the mining of hardrock minerals on U.S. public lands and to help develop the then sparsely populated West.
