CONTENTS

Preface Introduction Box 1.1--Contours--a way of plotting information on a map Geography Exercises Gravity and the San Francisco Bay Area Box 2.1--How do geophysicists measure gravity? Box 2.2--Isostasy Box 2.3--Plate Tectonics Exercises Magnetism and the San Francisco Bay Area Box 3.1--Playing with magnets Box 3.2--Rock magnetism Box 3.3--Bio-magnetism Box 3.4--How deep is the source of a magnetic anomaly? Exercises Conclusion Box 4.1--The Chicxulub Crater (or how gravity and magnetic data helped find the smoking gun that killed the dinosaurs) Local Field Activities References/Further Reading

TABLE

FIGURES

1. 2. 3. 4. 5.	Geologic Map Color gravity map Color magnetic map Satellite image with gravity contours Satellite image with aeromagnetic contours