Geology Lecture 1 — 70-Question Practice Test 1

Vocabulary flashcards covering key concepts in physical and historical geology, Earth's interior, plate tectonics, seismic waves, and associated features from the lecture notes.

Physical geology

The study of Earth's materials and the processes that shape the planet.

Historical geology

The study of Earth's history and geological time.

Hazards

Natural events that pose risks to life and property (e.g., earthquakes, volcanoes, tsunamis, tornadoes).

Ussher

James Ussher; proposed a young Earth based on biblical chronology, associated with catastrophism.

Catastrophism

The idea that Earth's landscape is shaped by sudden, short-lived, violent events.

Uniformitarianism

The present is the key to the past; slow, ongoing processes shape Earth.

Hutton

James Hutton; advocate of uniformitarianism.

Cuvier

Georges Cuvier; advocate of catastrophism and extinction events.

Lyell/Principles

Charles Lyell; author of The Principles of Geology, promoting uniformitarianism.

Seismic waves

Waves that travel through Earth to reveal its interior structure.

P-waves

Primary (compressional) seismic waves; travel through solids and liquids.

S-waves

Secondary (shear) seismic waves; travel only through solids.

P waves travel

Solids and liquids.

S waves travel

Solids only.

Moho

The Mohorovičić discontinuity; boundary between crust and mantle.

Outer core

Liquid iron-nickel alloy; generates Earth's magnetic field.

Inner core

Solid iron-nickel sphere at Earth's center.

Oceanic crust

Thin, dense crust primarily composed of basalt.

Continental crust

Thick, less dense crust composed mainly of granitic rocks.

Lithosphere

Rigid outer shell (crust + upper mantle) that moves as plates.

Asthenosphere

Plastic, weak layer of the upper mantle beneath the lithosphere.

Shadow zones

Seismic zones where certain waves are absent or deflected, indicating liquid outer core.

Upper mantle density

Typically around 3.3 g/cm³.

Lower mantle density

Typically around 5.6 g/cm³.

Mantle convection

Heat-driven circulation in the mantle that powers plate motion.

Plates ride on

Asthenosphere.

Plate rate

Movement measured in centimeters per year (cm/yr).

Divergent

Plates move apart.

Mid-ocean ridges

Undersea divergent boundaries where new ocean floor forms.

Rift valleys

Continental divergent boundaries forming rift valleys.

Convergent

Plates collide; can form mountain belts or subduction zones.

Andes

Andes Mountains formed by oceanic-continental subduction (O-C convergent).

Japan

Island arc formed by oceanic-continental convergence (O-C).

Himalayas

Mountain range formed by continental-continental collision (C-C).

San Andreas

Transform boundary in California; connects plate boundary segments.

Passive margins

Continental margins not currently at a plate boundary; no subduction.

Not a boundary

Isostasy is not a plate boundary; it’s buoyancy balance between crust and mantle.

Wegener

Alfred Wegener; proposed the theory of continental drift.

Pangea

Ancient supercontinent composed of all Earth's landmasses.

Drift evidence

Fossil distribution, matching coastlines, rock types, and past climate data supporting drift.

Rejected drift

Initially dismissed due to lack of a mechanism explaining plate movement.

Spreading by

Harry Hess; proposed seafloor spreading as a mechanism.

Stripes record

Paleomagnetic reversals recorded in seafloor rocks; stripes indicate past polarity changes.

Oldest ocean floor

About 200 million years old.

Heat flow highest

At mid-ocean ridges where new crust is formed.

Youngest floor

Found at mid-ocean ridges where new crust is created.

Paleomagnetism proves

Evidence for plate motion and seafloor spreading.

Plates move by

Ridge push and slab pull (and related gravitational mechanisms).

Slab pull

Dense subducting slabs sink and pull the rest of the plate.

Ridge push

Gravitational sliding at ridges pushing plates apart.

Pangea broke

Around 200 million years ago.

Subduction zones

Regions where one plate sinks beneath another, forming trenches and volcanic arcs.

Cascades

Continental volcanic arc in western North America formed by subduction.

O-O convergent

Oceanic–Oceanic convergence; forms island arcs and deep trenches.

C-C coll

Continental–Continental collision; builds major mountain belts.

Terranes

Fragments of crust accreted to a continent.

Isostasy

Gravitational balance between crust and mantle; crust floats on mantle.

Mountains balanced

Deep roots anchor mountains and balance loads with the mantle.

Erosion+isostasy

Erosion reduces load, causing isostatic rebound and uplift.

Denser crust

Sinks more readily due to greater density and buoyancy differences.

Transform faults connect

Ridge segments and offset lithospheric plates along transform boundaries.

Not transform

Moho–mantle boundary is not a transform boundary.

San Andreas connects

A transform boundary that links segments of the Pacific-North American plate boundary.