Geology, Earth Resources, and Climate Change

Engineering Data Analysis

Earth

a dynamic planet and constantly changing structure.

Core

interior, is composed of a dense, intensely hot mass of metal, mostly iron, thousands of kilometers in diameter. Solid in the center but more fluid in the outer core, this immense mass generates the magnetic field that envelops the earth.

Mantle

is surrounding the molten outer core. It is a hot, pliable layer of rock.

Crust

is the cool, lightweight, brittle rock outermost layer of the earth.

less

The mantle is much _____ dense than the core because it contains a high concentration of lighter elements, such as oxygen, silicon, and magnesium.

granitic

Crust under continents is predominantly _________

dense basaltic rock

oceanic crust is mainly _________

Antonio Snider

went so far as to publish a sketch showing how the two continents could fit together, jigsaw-puzzle fashion. Such reconstructions gave rise to the bold suggestion that perhaps these continents had once been part of the same landmass, which had later broken up.

Alfred Wegener

was struck not only by the matching coastlines, but by geologic evidence from the continents.

Glossopteris

fossil plant remains of which are found in limited areas of widely separated lands including India, southern Africa, and even Antarctica

Mesosaurus

fossils of a small reptile that supported the continential-drift theory

Pangaea

single supercontinent

Greek

Pangaea (_______ for “all lands”)

Continental drift

all the continental landmasses had once formed a single supercontinent, Pangaea (Greek for “all lands”), which had then split apart, the modern continents moving to their present positions via a process called _______

Tectonics

is the study of large scale movement and deformation of the earth’s outer layers.

Tectonic plates

relates such deformation to the existence and movement of rigid “plates” over a weaker, more plastic layer in the earth’s upper mantle

Lithosphere

outer solid layer of the earth

rock

Lithosphere came from Greek word “lithos” meaning ______

underneath the ocean

Lithosphere is thinnest ________, where it extends to a depth of about 50 kilometers (about 30 miles)

Asthenosphere

layer below the lithosphere

asthenes

Asthenosphere came from _________, meaning “without strength.”

Divergent plate boundary

lithospheric plates MOVE APART

volcanic activity

A great deal of ________ thus occurs at divergent plate boundaries

earthquakes

result of pulling apart of the plates of the lithosphere in the divergent plate boundary

Seafloor spreading ridges

are the most common type of divergent boundary worldwide, and it is already noted the formation of new oceanic lithosphere at these ridges.

continental rifting

most ocean basins are believed to have originated through ____________

triple junction

three rift zones meet

Convergent plate boundary

plates are moving toward each other

Continental crust

___________ is relatively low in density, so continental lithosphere is therefore buoyant with respect to the dense, iron rich mantle, and it tends to “float” on the asthenosphere.

Oceanic crust

__________ is more similar in density to the underlying asthenosphere, so oceanic lithosphere is less buoyant and more easily forced down into the asthenosphere as plates move together.

Oceanic lithosphere

most common to be at the leading edge of one or both of the converging plates.

subduction zone

one plate is carried down below (subducted beneath) another

island arc

At an ocean-ocean convergence, the result is commonly a line of volcanic islands, an _______.

continent-continent

Earthquakes are frequent during ___________ collision as a consequence of the large stresses involved in the process

Transform Plate Boundary

ridges consist of many short segments slightly OFFSET from one another

transform fault

offset is a special kind of fault, or break in the lithosphere

San Andreas Fault

example of a transform fault

Minerals

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

Crystalline

materials are solids in which the atoms or ions are arranged in regular, repeating patterns.

chemical compostion; crystal structure

The two fundamental characteristics of a mineral that together distinguish it from all other minerals are its __________ and its __________

Silicon and oxygen

Two most common elements in the earth’s crust are

Silicates

group is the largest compositional group of minerals, all of which are compounds containing silicon and oxygen, and most of which contain other elements as well

tetrahedral

The basic building block of all silicates is a __________ arrangement of four oxygen atoms (anions) around the much smaller silicon cation.

quartz

the best known silicate

Feldspars

most abundant group of minerals in the crust

Ferromagnesian

usually dark-colored (black, brown, or green)— that contain iron and/or magnesium, with or without additional elements

Olivine

simple ferromagnesian mineral, is a major constituent of earth’s mantle

Peridot

gem-quality olivines from mantle-derived volcanic rocks

Micas

sheet silicates, built on an atomic scale of stacked-up sheets of linked silicon and oxygen atoms. Because the bonds between sheets are relatively weak, the sheets can easily be broken apart

Clays

unusual among the silicates in that their structures can absorb or lose water, depending on how wet conditions are

Non-silicates

Most often, the common component is the same negatively charged ion or group of atoms

Native elements

mineral consists of a single chemical element

halide

metal + halogen elements

carbonate

metal +carbonate

sulfate

metal +sulfate

sulfide

sulfur without oxygen

oxides

metal +oxygen

Hydroxide

metal + hydroxyl

Rocks

a solid, cohesive aggregate of one or more minerals, or mineral materials

Igneous rock

rock formed by the solidification and crystallization of a cooling magma

fire

Igneous is derived from the Latin term ignis, meaning ________

magma

naturally occurring hot, molten rock material

Plutonic Igneous Rock

magma remains well below the surface during cooling

lower world

Plutonic Igneous Rock is derived from Pluto, the Greek god of the __________

Granite

most widely known example of a plutonic rock

lava

magma that flows out on the earth’s surface while still wholly or partly molten

volcanic rock

igneous rock formed at or close to the earth’s surface

basalt

most common volcanic rock

Sediments

are loose, unconsolidated accumulations of mineral or rock particles that have been transported by wind, water, or ice, or shifted under the influence of gravity, and redeposited

Sedimentary rocks

sediments are compacted or cemented together into a solid, cohesive mass

lithification

set of processes by which sediments are transformed into rock

Clastic sedimentary rocks

Formed from the products of the mechanical breakup of other rocks

klastos

Clastic sedimentary rocks came from the Greek word ______, meaning “broken”

Sandstone

is a rock composed of sand-sized sediment particles, 16 to 2 millimeters (0.002 to 0.08 inches) in diameter.

Shale

is made up of finer-grained sediments, and the individual grains cannot be seen in the rock with the naked eye.

Conglomerate

is a relatively coarse-grained rock, with fragments above 2 millimeters (0.08 inches) in diameter, and sometimes much larger.

Chemical sedimentary rocks

Form not from mechanical breakup and transport of fragments, but from crystals formed by precipitation or growth from solution.

Limestone

composed mostly of calcite (calcium carbonate). The chemical sediment that makes limestone may be deposited from fresh or salt water; under favorable chemical conditions, thick limestone beds, perhaps hundreds of meters thick, may form.

Rock salt

made up of the mineral halite, which is the mineral name for ordinary table salt (sodium chloride). A salt deposit may form when a body of salt water is isolated from an ocean and dries up

organic sediments

A sequence of sedimentary rocks may include layers of ___________

Metamorphic rock

one that has formed from another, preexisting rock that was subjected to heat and/or pressure.

changed form

Metamorphic comes from the Greek for “________.”

metaconglomerate

a metamorphosed conglomerate

metavolcanic

metamorphosed volcanic rock.

Quartzite

quartz-rich metamorphic rock, often formed from a very quartz-rich sandstone

Marble

is metamorphosed limestone in which the individual calcite grains have recrystallized and become tightly interlocking

foliation

In a rock subjected to directed stress, minerals that form elongated or platy crystals may line up parallel to each other. The resultant texture is described as ______, from the Latin for “leaf”

slate

is metamorphosed shale that has developed foliation under stress

Schist

a coarser-grained, mica-rich metamorphic rock in which the mica flakes are similarly oriented

Gneiss

minerals may be concentrated in irregular bands, often with darker, ferromagnesian-rich bands alternating with light bands rich in feldspar and quartz

rock cycle

a variety of geologic processes can transform any rock into a new rock of the same or a different class.

Economic mineralogy

is the study of resources that are valuable for manufacturing and are, therefore, an important part of domestic and international commerce.

metal bearing ores

minerals with unusually high concentrations of metals.

Metals

consumed in greatest quantity by world industry

Nonmetals

minerals are a broad class that covers resources from silicate minerals (gemstones, mica, talc, and asbestos) to sand, gravel, salts, limestone, and soils.

placer mining

ancient method of accumulating gold, diamonds, and coal

underground mining

Another ancient, and much more dangerous, method of accumulating gold, diamonds, and coal

Open-pit mines

used to extract massive beds of metal ores and other minerals

surface or strip mines

Half the coal used in the United States comes from

Over mountaintop removal

a coal mining method mainly practiced in Appalachia