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Flashcards in Test 2 Terms Deck (43):
1

Absolute dates

exact date of rocks, can be done by isotopic dating

2

Angular unconformity

Folded sedimentary rocks that are overlain by younger, more flat-lying strata
during deposition, folding and tilting occurred

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Correlation

process of establishing the equivalence of rocks of similar age in different areas

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Disconformity

gap in the rock record represents a period where erosion rather than deposition occurred

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Fossil

remains or traces of organisms preserved from the geologic past

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Half-life

The time required for one-half of the atoms of a radioactive substance to decay

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Index fossil

a fossil that is associated with a particular span of geologic time

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Isotope

Variaties of the same element that have different mass numbers: their nuclei contain the same number of protons but different numbers of neutrons

9

Nonconformity

younger sedimentary strata overlie older metamorphic or intrusive igneous rocks

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Paleontology

study of fossils

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Principle of Cross-Cutting Relationships

geologic features cut across rocks must form after the rocks they cut through

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Principle of Fossil Succession

A principle by which fossil organisms succeed one another in a definite and determinable order, and any time period can be recognized by its fossil content

13

Principle of inclusions

fragments of one rock unit that have been enclosed within another

14

Principle of lateral continuity

sedimentary beds originate as continuous layers that extend in all directions until they eventually grade into a different type of sediment or until they thin out at the edge

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Principle of superposition

most basic principle of relative dating: that in an under formed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below

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Radiometric dating

the procedure of calculating the absolute ages of rocks and minerals that contain certain radioactive isotopes

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relative dates

determining the chronological order or events by placing rocks and structures in their proper sequence or order

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types of fossilization

Permineralization, molds and casts, carbonization and impressions, amber

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Unconformity

a surface that represents a break in the rock record, caused by erosion and nondeposition

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Basin

circular down folded structure

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Brittle

Breaks

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Compression

Differential stress that shortens a rock body

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Deformation

General term for the processes of folding, faulting, shearing, compression, or extension of rocks as the result of various natural forces

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Dome

roughly circular upfolded structure

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Ductile

type of solid-state flow that produces a change in the size and shape of a rock body without fracturing. Occurs at depths where temperatures and confining pressures are high

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Elastic

sudden release of stored strain in rocks that result in movement along a fault

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Fault

break in the rock mass along which movement has occurred

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Fold

A bent layer or series of layers that were originally horizontal and subsequenetly deformed

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Shear

Stress that causes two adjacent parts of a body to slide past one another

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Stress

The force per unit area acting on any surface within a solid

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Tension

The type of stress that tends to pull a body apart

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Types of Faults

dip-slip
strike-slip
Oblique-slip

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Types of folds

Anticlines and synclines
Monoclines
Domes and Basins

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Earthquake

Vibration of Earth Produced by the rapid release of energy

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Epicenter

The location on Earth's surface that lies directly above the focus of an earthquake

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Hypocenter

focus of an earthquake

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Lithification

the process, generally involving cementation or compaction of converting sediments to solid rock

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Magnitude

an estimate of the total amount of energy released during an earth-quake, based on seismic records

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reflection

the redirection of some waves back to the surface when seismic waves hit a boundary between different Earth materials

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seismic waves

rapidly moving ocean wave generated by earthquake activity that is capable of inflicting heavy damage in coastal regions

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Asthenosphere

A subdivision of the mantle situated below the lithosphere
zone of weak material below 100 kilometers

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Conduction

The transfer of heat through matter by molecular activity

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Convection

The transfer of heat by the mass movement or circulation of a substance