Earth and Space Science Key Concepts: Geology, Planetary Formation, and Scientific Principles

Part of the upper mantle over which the lithosphere moves.

Asthenosphere

The big bang is a model for the evolution of the universe in which a dense hot state was followed by expansion, cooling and a less dense state.

Big Bang

The inner part of earth consisting of a liquid outer part and a solid inner part, mostly iron and nickel.

Core

The upper part of earth's lithosphere which is separated from the mantle by the Moho.

Crust

Remains or traces of prehistoric organisms preserved in rocks.

Fossil

A chart arranged so that the designation for the earliest part of geologic time appears at the bottom, most recent at the top.

Geologic Time Scale

The study of Earth but now it includes the study of the planets and moons in our solar system and even beyond. Physical geology is the study of Earth materials and processes. Historical geology studies the origin and evolution of earth.

Geology

An explanation for observations that is subject to continual testing.

Hypothesis

The 4 outer planets because they resemble Jupiter.

Jovian Planets

The outer, rigid part of earth, consisting of the upper mantle, oceanic crust, and continental crust.

Lithosphere

Surrounds the core and comprises about 83% of earth's volume.

Mantle

that all present-day organisms are related and that they descended with modifications from organisms that lived during the past

Organic Evolution

Segment of Earth's crust and upper mantle.

Plate

Theory holding that lithospheric plates move with respect to one another at divergent, convergent and transform boundaries.

Plate Tectonic Theory

A principle holding that we can interpret past events by understanding present day processed based on the idea that natural processes have always operated as they do now.

Principle of Uniformitarianism

Method is an orderly, logical approach that involves gathering and analyzing facts or data about the problem under consideration.

Scientific Method

Our solar system, the planets and sun formed from a rotating cloud of gas.

Solar Nebula Theory

A combination of related parts that interact in an organized manner.

System

The four inner planets are the terrestrial planets, because they are similar to terra, Latin for earth.

Terrestrial Planets

Means a speculative or conjectural view of something.

Theory

The smallest unit of matter that retains the characteristics of an element.

atom

The total number of protons and neutrons in an atom's nucleus.

atomic mass number

The number of protons in an atom's nucleus

atomic number

The processes whereby atoms join with other atoms

bonding

Any mineral with the negatively charged carbonate ion.

carbonate mineral

Any rock composed mostly of carbonate minerals (such as limestone and dolostone).

carbonate rock

Rock formed of minerals derived from materials dissolved during weathering.

chemical sedimentary rock

A substance made up of different atoms bonded together (such as water H2O and Quartz SiO2)

compound

Metamorphism taking place adjacent to a body of magma or beneath a lava flow from heat and chemically active fluids.

contact metamorphism

A solid with is atoms arranged in a regular three-dimensional framework.

crystalline solid

Rock made up of the solid particles derived from preexisting rocks, as in sandstone.

detrital sedimentary rock

Metamorphism in fault zones where rocks are subjected to high differential pressure.

dynamic metamorphism

Any aspect of geology involved in the search for and recovery of minerals and rocks of economic value.

economic geology

A substance composed of only one kind of atom (such as calcium Ca)

element

Sedimentary rock formed by inorganic chemical precipitation from evaporating water. (for example, rock salt and rock gypsum)

evaporite

An igneous rock that forms as lava cools and crystallizes or when pyroclastic materials are consolidated.

extrusive igneous rock

The record of prehistoric physical and biologic events in rocks.

geologic record

Rock formed when magma or lava cools and crystallizes and when pyroclastic materials become consolidated.

igneous rock

Igneous rock that cools and crystallizes from magma intruded into or formed within the crust.

intrusive igneous rock

Magma that reaches the surface.

lava

The process of converting sediment into sedimentary rock.

lithification

Molten rock material below the surface

magma

Any rock altered in the solid state from preexisting rocks by any combination of heat, pressure, and chemically active fluids.

metamorphic rock

AA naturally occurring, inorganic, crystalline solid having characteristic physical properties and a narrowly defined chemical composition.

mineral

Igneous rock that cools and crystallizes from magma intruded into or formed within the crust (plutonic)

plutonic rock

Fragmental materials, such as ash, explosively erupted from volcanoes.

pyroclastic materials

Metamorphism taking place over a large but usually elongated area resulting from heat, pressure, and chemically active fluids.

regional metamorphism

Aan aggregate of one or more minerals, as in granite and limestone, but also includes rocklike materials such as natural glass and alter organic material.

rock

A sequence of processes through which earth materials may pass as the are transformed from one rock type to another.

rock cycle

Any of about 2 dozen minerals common enough in rocks to be important for their identification and classification.

rock-forming mineral

Any rock composed of particles of preexisting rocks, minerals derived from solution by inorganic chemical processes or by the activities of organisms, or masses of altered organic matter in coal.

sedimentary rock

A mineral containing silica, a combination of silicon and oxygen, and usually one or more other elements.

silicate

An igneous rock that forms as lava cools and crystallizes or when pyroclastic materials are consolidated. (volcanic rock)

volcanic rock

When two continental plates converge, neither is subducted because of their great thickness and low and equal densities. As the two continental plates collide, a mountain range is formed in the interior of a new and larger continent.

continental-continental plate boundary

The hypothesis proposed by Alfred Wegener that all continents were once joined into a single landmass that broke apart, with various fragments(continents) moving with respect to one another.

continental drift

The boundary between two plates that move toward one another

convergent plate boundary

The temperature at which iron bearing minerals in a cooling magma attain their magnetism.

Curie point

The boundary between two plates that move apart, characterized by seismicity, volcanism, and the origin of new oceanic lithosphere.

divergent plate boundary

A Late Paleozoic association of plants found only on the Southern Hemisphere continents and India; named after its best-known genus, Glossopteris.

Glossopteris flora

One of six major Paleozoic continents; composed of South America, Africa, Australia, India, and parts of Southern Europe, Arabia, and Florida.

Gondwana

Localized zone of melting below the lithosphere; detected by volcanism at the surface.

hot spot

A Late Paleozoic, Northern Hemisphere continent made up of North America, Greenland, Europe, and Asia.

Laurasia

Any change, such as the average strength, in Earth's magnetic field.

magnetic anomaly

The area in which magnetic substances are affected by lines of magnetic force emanating from Earth.

magnetic field

The phenomenon involving the complete reversal of the north and south magnetic poles.

magnetic reversal

A physical phenomenon resulting from moving electricity and the spin of electrons in some solids, in which magnetic substances are attracted toward one another.

magnetism

When an oceanic plate is subducted beneath a continental plate, an andesitic volcanic mountain range is formed on the continental plate as a result of rising magma. The Andes in South America are one of the best examples of continuing mountain building at an oceanic-continental convergent plate boundary.

oceanic-continental plate boundary

An oceanic trench forms where one oceanic plate is subducted beneath another. On the nonsubducted plate, a volcanic island arc forms from the rising magma generated from the subducting plate. The Japanese islands are a volcanic island arc resulting from the subduction of one oceanic plate beneath another oceanic plate.

oceanic-oceanic plate boundary

An episode of mountain building involving deformation, usually accompanied by igneous activity, metamorphism, and crustal thickening.

orogeny

Alfred Wegener's name for a Late Paleozoic supercontinent made up of most of Earth's landmasses.

Pangaea

The phenomenon involving the origin of new oceanic crust at spreading ridges that then moves away from ridges and is eventually consumed at subduction zones.

seafloor spreading

A type of circulation of material in the asthenosphere during which hot material rises, moves laterally, cools and sinks, then is reheated and continues the cycle.

thermal convection cell

A type of fault that changes one kind of motion between plates into another type of motion; recognized on land as a strike-slip fault. (See San Andreas transform fault.)

transform fault

Plate boundary along which adjacent plates slide past one another and crust is neither produced nor destroyed.

transform plate boundary

A numerical dating technique relying on the ratio of 𝐶14 to 𝐶12 in organic substances; useful back to about 70,000 years ago.

carbon-14 dating

The dating process in which small linear tracks (fission tracks) resulting from alpha decay are counted in mineral crystals.

Fission-track dating

The time necessary for one-half of the original number of radioactive atoms of an element to decay to a stable daughter product; for example, the half-life of potassium 40 is 1.3 billion years.

half-life

Assigning an age in years before the present to geologic events before the present; numerical dates are determined by radioactive-decay dating techniques. (See relative dating.)

Numerical dating

A principle holding that an igneous intrusion or fault must be younger than the rocks it intrudes or cuts across.

principle of cross-cutting relationships

A principle holding that rock layers extend outward in all directions until they terminate.

principle of lateral continuity

A principle holding that sediments are deposited in horizontal or nearly horizontal layers.

principle of original horizontality

A principle holding that sedimentary rocks in a vertical sequence formed one on top of the other so that the oldest layer is at the bottom of the sequence whereas the youngest is at the top.

principle of superposition

The spontaneous change in an atom by emission of a particle from its nucleus (alpha and beta decay) or by electron capture, thus changing the atom to a different element.

Radioactive decay

The process of placing geologic events in their proper chronological order with no regard to when the events took place in terms of the number of years ago. (See numerical dating.)

Relative dating

The process of determining the age of a tree or wood in a structure by counting the number of annual growth rings.

Tree-ring dating

An unconformity below which strata dip at a steeper angle than those above

angular unconformity

A unit of sedimentary rock defined solely by its fossil content.

biostratigraphic unit

A general term referring to all biostratigraphic units such as range zones and concurrent range zones.

biozone

The shells, teeth, bones, or (rarely) the soft parts of organisms preserved in the fossil record.

body fossil

A biozone established by plotting the overlapping geologic ranges of fossils.

concurrent range zone

Refers to a sequence of sedimentary rocks deposited one after the other with no discontinuities, or only minor ones.

conformable

Demonstration of the physical continuity of stratigraphic units over an area; also refers to matching up time-equivalent events in different areas.

correlation

A type of unconformity above and below which the strata are parallel.

disconformity

The basic lithostratigraphic unit; a mappable unit of strata with distinctive upper and lower boundaries.

formation

Remains or traces of prehistoric organisms preserved in rocks.

fossil

A diagram showing a composite column of rocks arranged with the oldest at the bottom, followed upward by progressively younger rocks.

geologic column

Any easily identified fossil with a wide geographic distribution and short geologic range; useful for determining relative ages of strata in different areas.

guide fossil

Withdrawal of the sea from a continent or coastal area caused by emergence of the land with a resulting seaward migration of the shoreline.

marine regression

Invasion of a coastal area or much of a continent by the sea as sea level rises, resulting in a landward migration of the shoreline.

marine transgression

An unconformity in which stratified sedimentary rocks overlie an erosion surface cut into igneous or metamorphic rocks.

nonconformity