Geological Field Techniques

by Coe, Angela L.

• ISBN13: 9781444330625
• ISBN10: 1444330624
• Edition: 1st
• Format: Paperback
• Copyright: 2010-10-25
• Publisher: Wiley-Blackwell

Summary

The understanding of Earth processes and environments over geological time is highly dependent upon both the experience that can only be gained through doing fieldwork, and the collection of reliable data and appropriate samples in the field. This textbook explains the main data gathering techniques used by geologists in the field and the reasons for these, with emphasis throughout on how to make effective field observations and record these in suitable formats. Equal weight is given to assembling field observations from igneous, metamorphic and sedimentary rock types. There are also substantial chapters on producing a field notebook, collecting structural information, recording fossil data and constructing geological maps. The volume is in a robust and handy size, with colour coded chapters for ease of use and quick reference in the field.This textbook is designed for students, amateur enthusiasts and professionals who have a background in geology and wish to collect field data on rocks and geological features. Teaching aspects of this textbook include: step-by-step guides to essential practical skills such as using a compass-clinometer, drawing a geological map and making a field sketch; tricks of the trade, checklists, flow charts and short worked examples; over 200 illustrations of a wide range of field notes, maps and geological features; appendices with the commonly used rock description and classification diagrams; a supporting website hosted by Wiley Blackwell.

Author Biography

Dr Angela L. Coe specializes in sedimentology and stratigraphy and has over 20 years of experience of collecting geological field data in Europe, Asia, North and South America. Over this time, she has also designed and taught field geology courses for several UK universities and has led many field trips for international conferences and petroleum companies.

Dr Tom W. Argles is a geologist who has conducted structural and metamorphic fieldwork in several mountain belts (Alps, Himalaya, Betic Cordillera, Caledonides, Basin and Range) for 20 years. He has set up and taught field courses in a range of locations across the UK and Europe

Dr David A. Rothery is a volcanologist and planetary scientist. He has taught geology in the field for 30 years and has research experience of igneous rocks (including active volcanoes) in the Oman, Cyprus, Italy, the Andes, central America, NW USA, Hawaii and Western Australia.

Professor Robert A. Spicer is a palaeobotanist and sedimentologist with over 30 years field experience working in remote regions of Northern Alaska and northeastern Russia, China and Tibet, India, Australia, New Zealand, and Mexico.

Table of Contents

Preface

Acknowledgements

Introduction

A selection of general books and reference material on geology

Books on geological field techniques

Field equipment and safety

Introduction

The hand lens and binoculars

The compass-clinometer

Orientation of a dipping plane

Orientation of a linear feature

Triangulation: Determining location using a compass

Global positioning systems and altimeters

Measuring distance and thickness

Standard thickness and distance measurements

Use of the Jacob staff to measure the thickness of inclined strata

Classification and colour charts

Hammer, chisels and other hardware

The hardcopy field notebook

The laptop, netbook or PDA as a notebook

Writing equipment, maps and relevant literature

Writing equipment

Maps and relevant literature

Comfort, field safety and field safety equipment

Clothes, backpack/rucksack and personal provisions

Field safety

Field safety equipment

Conservation, respect and obtaining permission!

Further reading

Introduction to field observations at different scales

Introduction: What, where and how?

Defining the fieldwork objective

Deciding where to do the fieldwork

Locating your position

Scale of observation, where to start and basic measurements

Regional context

Whole exposure

Hand specimens

Overview of possible data formats

The field notebook

Introduction: The purpose of field notes

Field notebook layout

Preliminary pages

Daily entries

General tips

Field sketches: A picture is worth a thousand words

General principles: Aims, space and tools

Sketches of exposures

Sketching metre- and centimetre-scale features

Sketch maps

Written notes: Recording data, ideas and interpretation

Notes recording data and observations

Notes recording interpretation, discussion and ideas

Correlation with other data sets and interpretations

Recording palaeontological information

Introduction: Fossils are smart particles

Why are fossils important?

Collecting fossil data

Fossil types and preservation

Body fossil classification

Body fossil preservation

Trace fossils

Molecular fossils

Fossil distribution and where to find them

Transported or life position?

Sampling strategies

Sampling for biostratigraphic or evolutionary studies

Sampling of bedding surfaces and palaeoecology

Estimating abundance

Presence/absence and qualitative abundance estimates

Quantitative measures of abundance

How many samples are required?

Summary

Further reading

Recording features of sedimentary rocks and constructing graphic logs

Introduction

Description, recognition and recording of sedimentary deposits and sedimentary structures

Recording sedimentary lithology

Recording sedimentary structures

Graphic logs

Conventions for graphic logs

Constructing a graphic log

Rocks in space: Reconstructing sedimentary environments and their diagnostic features

Using sedimentary rocks to interpret climate change and sea-level change

Climate change

Sequence stratigraphy and relative sea-level change

Further reading

Recording features of igneous rocks

Equipment, basic tips and safety

Field relationships of igneous rocks

Relationships with surrounding rocks

Internal architecture: Joints and veins

Internal architecture: Other exposure-scale fabrics

Mineralogy and small-scale textures of igneous rocks

Petrologic type

Mineral texture and fabric

Recent and active volcanoes

Equipment and safety

Access

Observations

Further reading

Recording structural information

Equipment and measurement

Structural measurements and notations

Brittle structures: Faults, joints and veins

Planar brittle features - orientation

Determining past motion on brittle structures

Ductile structures: Shear zones, foliations and folds

Orientation of ductile planar features

Direction of shear/stretching: Stretching lineations

Sense of shear: Kinematic indicators

Magnitude of shear strain

Fold analysis

Further reading

Recording features of metamorphic rocks

Basic skills and equipment for metamorphic fieldwork

Field relations and context

Textures

Banding

Grain textures

Reaction textures

Mineralogy

Identifying common metamorphic minerals

Using mineral assemblages

Classification of metamorphic rocks

Unravelling metamorphism and deformation

Pre-kinematic features

Syn-kinematic features

Post-kinematic features

Further reading

Making a geological map

Principles and aims

Preparation and materials

Base maps and other aids

Equipment for mapping

Location, location, location

Equipment

Using base maps

Making a field map

Information to record on field maps

The evolving map

Sketch cross-sections

Mapping techniques

Traverse mapping

Contact mapping

Exposure mapping

Using other evidence

The geological map

Inking in the field map

Cross-sections

Fair copy maps

Digital maps and GIS

Further reading

Recording numerical data and use of instruments in the field

Data collection

Instrument calibration and base stations

Survey grid

Transport and protection of the instruments

Correlation with other data sets

Further reading

Photography

Sampling

Selecting and labelling samples

Samples for thin-sections

Orientated samples

Samples for geochemical analysis

Samples for mineral extraction

Samples for fossils

Sampling for regional studies

High-resolution sample sets

Labelling samples and their packaging

Practical advice

Packing and marking materials

Extraction of samples

Concluding remarks

Further reading on scientific report writing

References

General

Fossils

Sedimentary

Igneous

Structural

Metamorphic

Mapping

Index

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