Geology in the Field

by Robert R. Compton (Stanford Univ.)

• ISBN13: 9780471829027
• ISBN10: 0471829021
• Format: Hardcover
• Copyright: 1985-08-01
• Publisher: Wiley

Summary

Replaces Compton'sManual of Field Geology (1962). A guide to advances in the increasingly broad and interpretive discipline of formation mapping theory. Thorough, yet compact enough for use in the field, it consists of brief descriptions of textures and structures useful in interpreting depositional environments, kinds of volcanic activity, and plutonic events and conditions. Included are procedures often reserved for the laboratory or office: staining rocks, correcting orientations of current indicators, constructing profile sections of folds, measuring strains, making photogeologic interpretations, and more. Covers pre-field considerations, methods of observation and measurement, recognition of key geologic features, and preparation of a report. Illustrated with composite drawings. Fourteen appendixes provide systemized data and procedures.

Table of Contents

Philosophy and Organization of a Field Study
Field Geology in General	1	(1)
Geologic Maps and Mapping	2	(1)
Selecting a Field Study	3	(1)
Reconnaissance	4	(1)
Preparations for the Field	5	(1)
Work in the Field	6	(2)
Completing a Field Study	8	(1)
References Cited	9	(1)
Basic Equipment and Its Uses
Equipment for Sampling and Recording	10	(3)
Selecting and Using a Hand Lens	13	(1)
Materials and Methods for Staining Rocks	14	(2)
The Compass	16	(1)
Taking a Compass Bearing	17	(2)
The Clinometer; Calculating Vertical Distances	19	(1)
The Hand Level	19	(1)
Taping and Pacing Distances	20	(1)
References Cited	21	(1)
Basic Procedures at Outcrops
Observations in the Field	22	(3)
Interpretation of the Outcrop	25	(2)
Taking Field Notes	27	(5)
Drawing and Photographing Outcrops	32	(2)
Measuring Strike and Dip	34	(4)
Measuring Attitudes of Linear Features	38	(2)
Finding and Collecting Fossils	40	(5)
Collecting Rock Samples	45	(2)
References Cited	47	(1)
Identifying Rocks in the Field
General Rationale	48	(1)
Textures of Sedimentary Rocks	48	(7)
Naming Sedimentary Rocks	55	(6)
Textures of Igneous Rocks	61	(4)
Naming Igneous Rocks	65	(3)
Textures of Metamorphic Rocks	68	(4)
Naming Metamorphic Rocks	72	(2)
References Cited	74	(1)
Mapping Rock Units and Structures
A Geologic Pace and Compass Traverse	75	(5)
Finding and Tracing Contacts Between Rock Units	80	(3)
Refining and Correlating Geologic Units	83	(3)
Mapping Geologic Structures	86	(2)
Rapid (Reconnaissance) Geologic Mapping	88	(1)
Outcrop Maps, Maps of Surficial Deposits, and Bedrock Maps	89	(3)
Mapping Engineering Geologic Units	92	(6)
References Cited	98	(1)
Geologic Mapping on a Topographic Base
Topographic Maps	99	(2)
Preparations for a Mapping Project	101	(1)
Locating Points in the Field	101	(5)
Interpretation of Geologic Lines on a Topographic Base	106	(2)
Office Routines; Constructing Vertical Cross Sections	108	(3)
References Cited	111	(1)
Use of Aerial Photographs and Other Remote Imagery
Conventional Aerial Photographs	112	(6)
Other Kinds of Remote-sensed Imagery	118	(2)
Photogeologic Studies	120	(3)
Equipment and Preparations for a Field Project	123	(1)
Determining Photograph Scales and Orientations	124	(1)
Locating Photo Points in the Field	125	(1)
Geologic Mapping in the Field	126	(1)
Compiling Data from Aerial Photographs	127	(2)
Cross Sections from Aerial Photographs	129	(1)
Compiling a Map by the Radial Line Method	130	(3)
References Cited	133	(2)
Mapping with the Plane Table and Alidade
The Alidade	135	(1)
Care and Adjustments in the Field	136	(1)
The Plane Table, Mapping Sheets, and Tripod	137	(2)
Stadia Measurements	139	(6)
Methods for Long Sights	145	(2)
Preparations for a Plane Table Project	147	(1)
Horizontal and Vertical Control	148	(7)
Locating Stations for Stadia Mapping	155	(3)
Stadia Mapping	158	(3)
References Cited	161	(1)
Primary Features of Marine Sedimentary Rocks
Beds and Bedding	162	(2)
Depositional Bed Forms and Structures	164	(5)
Postdepositional Structures	169	(2)
Paleocurrent Direction and Paleoslope Direction	171	(5)
Trace Fossils; Bioturbation	176	(2)
Unconformities; Rates of Deposition	178	(2)
Environments Affected by the Tides	180	(4)
Beach and Shelf Deposits	184	(4)
Marginal and Basinal Deposits of the Deep Sea	188	(5)
Structures Indicating Stratigraphic Facing (Tops) of Beds	193	(1)
References Cited	194	(3)
Surficial Sediments; Continental Environments
The Quaternary Record	197	(1)
Alluvial Deposits	198	(2)
Lake Deposits	200	(1)
Eolian Deposits	201	(2)
Glacial Deposits	203	(3)
Colluvium and Soil Creep	206	(1)
Landslides, Nonvolcanic Debris Flows, and Rockfalls	207	(3)
Periglacial Deposits and Features	210	(2)
Soils	212	(7)
References Cited	219	(3)
Stratigraphic Sections
Preliminary Steps	222	(1)
Subdividing and Describing a Section	223	(2)
Covered, Deformed, or Laterally Variable Strata	225	(4)
Measurement with the Jacob Staff	229	(4)
Measurement using Eye Height and a Brunton Compass	233	(1)
Tape-Compass-Clinometer Method	234	(2)
Transit Method	236	(1)
Plane Table Methods	237	(1)
Presenting Stratigraphic Sections	238	(3)
References Cited	241	(1)
Features of Deformed Rocks
Early Formed Deformational Features	242	(1)
Determining Directions and Amounts of Strain	243	(6)
Folds	249	(6)
Foliations, Cleavages, and Related Lineations	255	(4)
Faults	259	(6)
Joints	265	(1)
Melanges	266	(3)
References Cited	269	(3)
Volcanic Structures and Field Relations
Map Units, Stratigraphy, and Ages	272	(2)
Subaerial Basalts and Other Fluid Lavas	274	(4)
Subaqueous Basaltic Lavas and Hyaloclastic Deposits	278	(2)
Flows and Domes of Viscous Lava	280	(2)
Pyroclastic Deposits Produced by Explosions	282	(6)
Fragmental Rocks Formed Without Explosion	288	(2)
Volcanic Feeders and Related Intrusions	290	(2)
References Cited	292	(4)
Field Studies of Plutons
Rock Units, Ages, and Depth Relations	296	(4)
Fabrics of Plutonic Rocks	300	(3)
Inclusions in Plutons	303	(2)
Layering (Banding) in Plutons	305	(2)
Schlieren and Related Structures	307	(1)
Pegmatite and Other Volatile-related Rocks	308	(4)
Fracture Systems in Plutons	312	(3)
Autometamorphism of Plutons	315	(1)
References Cited	316	(3)
Field Studies of Metamorphic Rocks
Protoliths of Metamorphic Rocks	319	(2)
Metamorphic Mineral Reactions	321	(2)
Metamorphic Zones Based on Minerals or Textures	323	(2)
Metasomatism	325	(4)
Segregated Metamorphic Rocks; Gneisses	329	(3)
Migmatites	332	(1)
Hydrothermal Alteration	333	(3)
Age of Metamorphism; Sequence of Metamorphic Events	336	(2)
References Cited	338	(3)
Preparing Illustrations and Writing Reports
From Field Study to Report Writing	341	(1)
Major Illustrations First	342	(8)
Photographs, Drawings, and Diagrams	350	(3)
Designing the Report	353	(4)
The Writing Itself	357	(2)
Specific Parts of the Report; Format	359	(2)
References Cited	361	(2)
Appendixes
1. Equipment and Supplies for Geologic Field Work	363	(1)
2. Abbreviations of Geologic Terms	364	(2)
3. Percentage Diagrams for Estimating Rock Compositions by Volume	366	(2)
4. Strength (Coherence) and Hardness of Rocks and Sediments	368	(1)
5. Township-section Cadastral System of the U.S. Bureau of Reclamation	369	(1)
6. Use of Charts for Standardizing Colors of Sediments and Rocks	370	(2)
7. Symbols for Geologic Maps	372	(4)
8. Lithologic Patterns for Stratigraphic Columns and Cross Sections	376	(2)
9. Fossil and Structure Symbols for Columnar Sections and Field Notes	378	(1)
10. Major Geochronologic and Chronostratigraphic Units in Use by the U. S. Geological Survey	379	(1)
11. Natural Trigonometric Functions, at 0.5° Intervals	380	(1)
12. Equivalence Among Common English and Metric Units	381	(1)
13. Table for Interconversion of True Dip and Apparent Dip	382	(1)
14. Equal-area (Schmidt) Stereographic Net	383	(2)
Index	385