This page provides links to diagrams or documents drafted by Dr. Bruce Railsback for basic geology classes at the University of Georgia. Educators are welcome to use these documents in their teaching, so long as the images are not reproduced in publications and are not used for financial gain. Persons wishing to use these documents in publications should contact Email to Railsback (

Basic Concepts
Scales of Observation
Facts, theories, and hypotheses
An introduction to maps, cross-sections, and 3D diagrams.
Geologic exposures in the field - sources of geological information
Earth at a glance - a diagramatic summary of key features
Evidence regarding the age of the Earth
Age of the Earth from Earth's bulk lead isotopes
The standard geological time scale
The standard and two non-standard geological time scales

Plate Tectonics
Large-scale theories of the Earth
Evidence for plate tectonics
Diagram showing general features of plate tectonics
Diagram showing the three kinds of plate tectonic boundaries
Diagram showing the Crust, Mantle, Lithosphere, and Asthenosphere
Cross-Section of the Earth to Scale
Divergent plate boundaries
Triple junctions of divergent plate boundaries
Convergent plate boundaries
Transform plate boundaries sketches.
A map showing ages of the Hawaiian Islands
Four diagrams explaining volcanic chains:
      The traditional hotspot model with a mantle plume
      A hotspot model with a fertile blob
      The propagating-crack model
      The non-propagating-crack model
A diagram showing possible driving forces for plate tectonics

A definition of a mineral, and some mineral properties
Simple crystal models
The chemical compositon of the crust
Some non-silicate minerals
The silica tetrahedron
Silicate mineral structures I
Silicate mineral structures II - top of diagram
Silicate mineral structures II - bottom of diagram
Silicate mineral structures III
A list of silicate minerals
Silicate minerals in igneous rocks

Igneous Rocks
The three fundamental kinds of rocks
Crystallization of igneous rocks
Classification of igneous rocks
Occurrence of igneous rocks
List of bodies of plutonic rocks
Diagram showing bodies of plutonic rocks
Kinds of volcanic material
Kinds/Forms of volcanoes
Kinds/Forms of volcanoes II
Plate Tectonic settings of volcanoes
Sizes of pyroclastic eruptions
An explanation of columnar jointing
The long-term significance of volcanism

Sedimentary Rocks
Three fundamental kinds of sedimentary rocks
Characteristics of sediments
Characteristics of sediments II: Layering
Four fundamental components of sedimentary rocks
A possible sedimentary rock
Sediments, the environments in which they accumulate, and the sedimentary rocks they form
Highly generalized locations of where sediments accumulate
Origins of breccias
Lithification of sediments
Possible diagenesis of sandstones
The path from weathering to lithification

Metamorphic Rocks
Foliation and lineation
A schematic explanation of metamorphism - Part I
A schematic explanation of metamorphism - Part II
Some metamorphic rocks
Stability fields of some familiar minerals under metamorphic conditions
Metamorphic conditions and locations

Some closing observations about rocks
Proportions of rock types in earth's crust
Origins of breccias
Properties and use of different kinds of rocks

Rock Deformation
Steno's Principles - starting points for considering structures in rocks
Three kinds of physical stress that deform rocks
Kinds of rock deformation
Stress and deformation: a six-fold matrix

Faults: a definition and two handy terms
Simple faults
More faults
Drag folds
Surface expression of faults

Folds, Basins, and Domes
Simple Folds
Plunging Folds
Doubly-plunging Folds
Scales of folding in sedimentary vs. metamorphic rocks
A geologic map of Michigan
A geologic map of Tennessee, Kentucky, southern Illinois, southern Indiana, and southern Ohio
A labeled map of Domes and Basins in Tennessee, Kentucky, southern Illinois, southern Indiana, and southern Ohio
A cross-section from Tennessee to central Illinois
Problems in Folding - Part 1
Problems in Folding - Part 2 - the results

Earthquakes and Seismology
Earthquakes and elastic rebound
Earthquake Waves I
Earthquake Waves II
Locating Earthquakes I
Locating Earthquakes II
Controls on Earthquake Impact
Measuring Earthquakes I
Measuring Earthquakes II
Dangers of Earthquakes
Prediction of Earthquakes
Earthquakes and Plate Tectonics
Locations of Intraplate Earthquakes

Earth's Interior
Evidence about Earth's Interior
Observations of Seismic Waves Across the Earth
(Inferred) Passage of S waves through the Earth
(Inferred) Passage of P waves through the Earth
Conclusions about Earth's Interior

Petroleum Accumulations
An Idealized Petroleum Accumulation
Basic Elements Required for a Petroleum Accumulation
Sketches of Petroleum Traps
Exploitation of a Discovered Petroleum Accumulation
Depth Distribution of US Oil.
Basics of Drilling an Oil Well.
Sequential Views of Drilling an Oil Well.
Things that Can Go Wrong in Drilling an Oil Well.

This is the first of two pages. You can go onward to page 2

Email to Railsback (
Railsback's main web page
UGA Geology Department web page