Geology & Meteorology Flashcards

Geology and Meteorology Vocabulary Flashcards

Relative vs. Numerical Dating

Orders events; numerical dating gives exact ages.

Principle of Superposition

In undisturbed layers, the oldest rocks are on the bottom.

Unconformity

A gap in the geological record due to erosion or non-deposition.

Half-life

Time for half of a radioactive substance to decay.

Most Abundant Gas in Atmosphere

Nitrogen (78%).

Layers of the Atmosphere

Troposphere, Stratosphere, Mesosphere, Thermosphere.

Fossil Assemblage

A group of different fossils found together in a rock layer.

Index Fossil

A fossil used to define and identify geologic periods.

Passive Continental Margin

A tectonically inactive edge with wide shelf, slope, and rise.

Mid-Ocean Ridges

Seafloor spreading and new crust formation.

Breaking Waves

When wave height/wavelength ratio exceeds 1/7.

Wave Base

Depth equal to half the wavelength, where orbital motion stops.

Salinity

Amount of dissolved salts in water.

Bathymetry

Study of underwater depth and ocean floor features.

Fetch

The distance wind travels over open water.

Albedo

Reflectivity of a surface.

CO₂ Addition to Atmosphere

Mainly by burning fossil fuels.

Heat Transfer from Sun to Earth

By radiation.

Humidity

Amount of water vapor in the air.

Relative Humidity

Percentage of water vapor present vs max the air can hold.

Dew Point

Temperature where air becomes saturated and dew forms.

Major Cloud Types

Cirrus, Cumulus, Stratus, Cumulonimbus.

Standard Atmospheric Pressure

1013.25 millibars at sea level.

Isobar

A line of equal pressure on a weather map.

Cold Front

When cold air pushes under warm air, causing storms.

Cyclone

A low-pressure system with rotating winds.

Principle of Superposition

In undisturbed sedimentary layers, the oldest rocks are at the bottom.

Principle of Original Horizontality

Sedimentary layers are originally deposited horizontally.

Principle of Cross-Cutting Relationships

Any feature that cuts through rocks is younger than the rocks it cuts.

Principle of Inclusions

Fragments inside a rock are older than the rock itself.

Faunal Succession

Fossils occur in a predictable order; used to correlate rock layers.

Disconformity

A gap in the rock record between parallel sedimentary layers.

Angular Unconformity

Older tilted or folded rocks overlain by flat-lying layers.

Nonconformity

Sedimentary layers above eroded igneous or metamorphic rock.

Divisions of Geologic Time Scale

Eon > Era > Period > Epoch > Age.

Example of Geological Time Divisions

Phanerozoic Eon > Cenozoic Era > Quaternary Period > Holocene Epoch.

Important Criteria for Fossilization

Rapid burial, hard parts, lack of oxygen, presence of sediment.

Trace Fossils

Evidence of organism activity like movement or feeding.

Examples of Trace Fossils

Tracks, burrows, coprolites, feeding marks, resting traces.

Active Continental Margin

Located at plate boundaries with earthquakes, volcanoes, and trenches.

Subduction

When one tectonic plate sinks beneath another.

Features of Convergent Margins

Trenches, volcanic arcs, earthquakes, accretionary wedges.

Thermocline

A layer where temperature drops quickly with depth.

Pycnocline

A layer where water density increases rapidly with depth.

Terrigenous Sediments

From land, formed by erosion and carried by rivers.

Biogenous Sediments

From remains of marine organisms like shells.

Hydrogenous Sediments

From minerals that precipitate directly from seawater.

What Increases Ocean Salinity?

Evaporation and sea ice formation.

What Decreases Ocean Salinity?

Rainfall, river runoff, and melting ice.

Bathymetry Description

The measurement and mapping of ocean floor depth and features.

Crest of a Wave

The highest point of a wave.

Trough of a Wave

The lowest point of a wave.

Wave Height

The vertical distance between crest and trough.

Wavelength

The horizontal distance between two wave crests.

Orbital Motion in Waves

Water particles move in circular paths beneath surface waves.

Tides

Regular sea level changes caused by Moon and Sun gravity.

What a Sling Psychrometer Measures

Relative humidity and dew point using wet and dry bulb temps.

How a Sling Psychrometer Works

Evaporation cools the wet bulb; the temp difference indicates humidity.

Cirrus Clouds

Wispy, high-altitude clouds.

Cumulus Clouds

Puffy, cotton-like clouds.

Stratus Clouds

Flat, gray, layered clouds.

Cumulonimbus Clouds

Tall storm clouds that can produce thunderstorms.