Geologic Maps: A Practical Guide to Preparation and Interpretation by Edgar W. Spencer
221 pages, $46.95 list
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Geologic Maps
A Practical Guide to Preparation and Interpretation
Third Edition
Geologic maps supply a wealth of information about the surface and shallow subsurface of the earth. The types of materials that are present in a location and the three-dimensional structure of the bedrock both can be gleaned from a clearly prepared geologic map. Geologists, civil and environmental engineers, land-use planners, soil scientists, and geographers commonly use geologic maps as a source of information to facilitate problem solving and identify the qualities of a region. Maps reveal the position of many types of natural hazards, indicate the suitability of the land surface for various uses, reveal problems that may be encountered in excavation, provide clues to the natural processes that shape an area, and help locate important natural resources.

Suitable for lab courses in structural geology as well as field geology work, Spencer describes representative examples of features found on geologic maps and outlines procedures for interpretation and projection. Geometric techniques are explained using a step-by-step approach. Coverage of mapping methods includes tools that provide necessary data, such as Google Earth, GPS, GIS, LiDAR maps, drones, and aerial photographs. Challenging and engaging exercises throughout the text involve students in the mapping process and stimulate an appreciation of the extent and precision of information presented in geologic maps.

Regional geology is an important component of lab and field mapping projects. As such, the Third Edition includes new maps of the Gulf of Mexico Coastal Plain, Rocky Mountain Front Range, Yellowstone region, Moab, Utah, Shenandoah National Park, and Hawai’i. A new chapter devoted to tectonic maps also broadens students’ exposure. Ed Spencer brings over 45 years of teaching experience to the text along with valuable insight and clarity into the interpretation and preparation of geologic maps.
“There are a wide range of structural examples used throughout the book, which makes it ideal for preparing students for whatever geologic career they are heading into. Useful map interpretation and concept questions.” — Shannon Dulin, University of Oklahoma

“This is a fantastic book, obviously meticulously prepared by someone with enormous experience in producing and interpreting geological maps. The steps are clear and the book will be an asset to any student enrolling in field camp.” — Eric Ferré, Southern Illinois University
Table of Contents
1. Maps and Images Used in the Study of Earth
Types of Information You Can Obtain from Maps and Images / Base Maps / Oblique Aerial Photographs / Vertical Aerial Photographs / Orthophotographs / Remote Sensing Images / Google Earth / Side-Looking Airborne Radar (SLAR) Images / Geologic Maps / Geologic Cross Sections / Geologic Block Diagrams / LiDAR Maps / Structure Contour Maps / Tectonic Maps / Land-Use Maps Derived from Geologic Maps / Professional Uses of Geologic Maps

2. Base Maps
Map Projections / Topographic Maps

3. Preparation of Geologic Maps
Preliminary Preparations / Making a Reconnaissance Survey of the Area / Collecting and Recording Observations / Determining Location with GPS / Use of Drones in Mapping / Describing the Outcrop / Making Measurements with Compasses / Compiling Field Observations on the Base Map / Interpreting the Data / Field Checking Your Interpretation / Preparing the Final Map

4. Identification and Description of Sedimentary Rocks
Field Description of Sedimentary Rocks / Environments of Deposition / Primary Features in Sedimentary Rocks / Textural Variations in Sedimentary Rocks / Primary Features Found on Bedding Surfaces

5. Use of Aerial Photographs in Mapping
Vertical Photographs / Identifying Surficial and Bedrock Materials on Aerial Photographs

6. Interpretation of Surficial Geologic Maps
Uses of Surficial Geologic Maps / Types of Unconsolidated Materials Shown on Geologic Maps

7. Introduction to Geologic Maps of Bedrock
Primary Shape of Sedimentary Rock Bodies / Structure Contour Maps

8. Geologic Maps of Homoclinal Beds
Patterns of Homoclinal Beds on Geologic Maps / V-Shaped Contact Patterns on Geologic Maps / Determining the Strike and Dip of a Plane from Three Points of Known Elevation on the Plane / Tracing Plane Contacts through the Topography / Layer Thickness and Width on Maps / Constructing Cross Sections of Homoclinal Beds

9. Unconformities
Unconformity Patterns on Geologic Maps

10. Folds on Geologic Maps
Fold Geometry / Fold Patterns on Geologic Maps / Constructing Cross Sections of Folded Rocks / Tracing Folds through the Topography / Structure Contour Maps of Folded Strata

11. Faults on Geologic Maps
Fault Nomenclature / Cross-Section Construction in Faulted Areas / High-Angle Faults / Patterns along Strike-Slip Faults / Low-Angle Faults

12. Igneous and Metamorphic Rocks
Appearance of Plutons on Geologic Maps / Nomenclature and Classification of Intrusions

13. Tectonic and Regional Maps

Appendix A: Safety in the Field
Appendix B: Geologic Maps and Explanations