McGraw-Hill Dictionary of Geology and Mineralogy Second Edition McGraw-Hill New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto All text in the dictionary was published previously in the McGRAW-HILL DICTIONARY OF SCIENTIFIC AND TECHNICAL TERMS, Sixth Edition, copyright ᭧ 2003 by The McGraw-Hill Companies, Inc. All rights reserved. McGRAW-HILL DICTIONARY OF GEOLOGY AND MINERALOGY, Second Edi- tion, copyright ᭧ 2003 by The McGraw-Hill Companies, Inc. All rights reserved. Printed in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. 1234567890 DOC/DOC 09876543 ISBN 0-07-141044-9 This book is printed on recycled, acid-free paper containing a mini- mum of 50% recycled, de-inked fiber. This book was set in Helvetica Bold and Novarese Book by the Clarinda Company, Clarinda, Iowa. It was printed and bound by RR Donnelley, The Lakeside Press. McGraw-Hill books are available at special quantity discounts to use as premi- ums and sales promotions, or for use in corporate training programs. For more information, please write to the Director of Special Sales, McGraw-Hill, Professional Publishing, Two Penn Plaza, New York, NY 10121-2298. Or contact your local bookstore. Library of Congress Cataloging-in-Publication Data McGraw-Hill dictionary of geology and mineralogy — 2nd. ed. p. cm. “All text in this dictionary was published previously in the McGraw-Hill dictionary of scientific and technical terms, sixth edition, —T.p. verso. ISBN 0-07-141044-9 (alk. paper) 1. Geology—Dictionaries. 2. Mineralogy—Dictionaries. I. Title: Dic- tionary of geology and mineralogy. II. McGraw-Hill dictionary of scientific and technical terms. 6th ed. QE5.M3654 2003 550Ј.3—dc21 2002033173 Staff Mark D. Licker, Publisher—Science Elizabeth Geller, Managing Editor Jonathan Weil, Senior Staff Editor David Blumel, Staff Editor Alyssa Rappaport, Staff Editor Charles Wagner, Digital Content Manager Renee Taylor, Editorial Assistant Roger Kasunic, Vice President—Editing, Design, and Production Joe Faulk, Editing Manager Frank Kotowski, Jr., Senior Editing Supervisor Ron Lane, Art Director Thomas G. Kowalczyk, Production Manager Pamela A. Pelton, Senior Production Supervisor Henry F. Beechhold, Pronunciation Editor Professor Emeritus of English Former Chairman, Linguistics Program The College of New Jersey Trenton, New Jersey vi How to Use the Dictionary ALPHABETIZATION. The terms in the McGraw-Hill Dictionary of Geology and Mineralogy, Second Edition, are alphabetized on a letter-by-letter basis; word spacing, hyphen, comma, solidus, and apostrophe in a term are ignored in the sequencing. For example, an ordering of terms would be: abnormal fold acre-yield a-b plane Agassiz orogeny ACF diagram Age of Fishes FORMAT. The basic format for a defining entry provides the term in boldface, the field is small capitals, and the single definition in lightface: term [FIELD] Definition. A field may be followed by multiple definitions, each introduced by a bold- face number: term [FIELD] 1. Definition. 2. Definition. 3. Definition. A simple cross-reference entry appears as: term See another term. A cross reference may also appear in combination with definitions: term [FIELD] 1. Definition. 2. See another term. CROSS REFERENCING. A cross-reference entry directs the user to the defining entry. For example, the user looking up “abyssal” finds: abyssal See plutonic. The user then turns to the “P” terms for the definition. Cross references are also made from variant spellings, acronyms, abbreviations, and symbols. aenigmatite See enigmatite. aggradation See accretion. barkhan See barchan. ALSO KNOWN AS ...,etc. A definition may conclude with a mention of a synonym of the term, a variant spelling, an abbreviation for the term, or other such information, introduced by “Also known as ...,” “Also spelled ...,” “Abbreviated ...,” “Symbolized ...,” “Derived from ....” When a term has vii more than one definition, the positioning of any of these phrases conveys the extent of applicability. For example: term [FIELD] 1. Definition. Also known as synonym. 2. Definition. Symbolized T. In the above arrangement, “Also known as . .” applies only to the first defini- tion; “Symbolized . .” applies only to the second definition. term [FIELD] Also known as synonym. 1. Definition. 2. Definition. In the above arrangement, “Also known as . .” applies to both definitions. MINERAL FORMULAS. Mineral definitions may include a formula indicat- ing the composition. viii Fields and Their Scope [GEOCHEM] geochemistry—The field that encompasses the investigation of the chemical composition of the earth, other planets, and the solar system and universe as a whole, as well as the chemical processes that occur within them. [GEOL] geology—The study or science of earth, its history, and its life as recorded in the rocks; includes the study of the geologic features of an area, such as the geometry of rock formations, weathering and erosion, and sedimentation. [GEOPHYS] geophysics—The branch of geology in which the principles and practices of physics are used to study the earth and its environment, that is, earth, air, and (by extension) space. [MINERAL] mineralogy—The study of naturally occurring inorganic sub- stances, called minerals, whether of terrestrial or extraterrestrial origin. [PALEOBOT] paleobotany—The study of fossil plants and vegetation of the geologic past. [PALEON] paleontology—The study of life in the geologic past as recorded by fossil remains. [PETR] petrology—The branch of geology dealing with the origin, occurrence, structure, and history of rocks, especially igneous and metamorphic rocks. ix Pronunciation Key Vowels Consonants aasinbat, thatbasin bib, dribble a¯ as in bait, crate ch as in charge, stretch a¨ as in bother, father d as in dog, bad easinbet, netfasin fix, safe e¯ as in beet, treatgasin good, signal iasinbit, skithasin hand, behind ¯ı as in bite, lightjasin joint, digit o¯ as in boat, note k as in cast, brick o˙ as in bought, tautkasin Bach (used rarely) u˙ as in book, pull l as in loud, bell u¨ as in boot, poolmasin mild, summer ə as in but, sofa nasinnew, dent au˙ as in crowd, power n indicates nasalization of preced- o˙ iasinboil, spoil ing vowel yə as in formula, spectacular ŋ as in ring,single yu¨ as in fuel, mule p as in pier, slip rasinred, scar Semivowels/Semiconsonants sasinsign, post wasinwind, twin sh as in sugar, shoe yasinyet, onion tasintimid, cat th as in thin, breath Stress (Accent) th as in then, breathe precedes syllable with primary vasinveil, weave stress zasinzoo, cruise zh as in beige, treasure precedes syllable with secondary stress Syllabication и Indicates syllable boundary precedes syllable with variable ¦ when following syllable is or indeterminate primary/ unstressed secondary stress x Preface The McGraw-Hill Dictionary of Geology and Mineralogy provides a compendium of more than 9000 terms that are central to a broad range of geological sciences and related fields. The coverage in this Second Edition is focused on the areas of geochemistry, geology, geophysics, mineralogy, paleobotany, paleontology, and petrology, with new terms added and others revised as necessary. Geology deals with the solid earth and the processes that formed and modified it as it evolved. Related disciplines include the study of the physics of the earth (geophysics); earth chemistry, composition, and chemical changes (geo- chemistry); the composition, properties, and structure of minerals (mineral- ogy); the description, classification, origin, and evolution of rocks (petrology); and the study of ancient life (paleontology). All of the definitions are drawn from the McGraw-Hill Dictionary of Scientific and Technical Terms, Sixth Edition (2003). Each definition is classified according to the field with which it is primarily associated; if it is used in more than one area; it is identified by the general label [GEOLOGY]. The pronunciation of each term is provided along with synonyms, acronyms, and abbreviations where appropriate. A guide to the use of the Dictionary appears on pages vii-viii, explaining the alphabetical organization of terms, the format of the book, cross referencing, and how synonyms, variant spellings, abbreviations, mineral formulas, and similar information are handled. The Pronunciation Key is pro- vided on page x. The Appendix provides conversion tables for commonly used scientific units as well as revised geologic time scale, periodic table, historical information, and useful listings of geological and mineralogical data. It is the editors’ hope that the Second Edition of the McGraw-Hill Dictionary of Geology and Mineralogy will serve the needs of scientists, engineers, students, teachers, librarians, and writers for high-quality information, and that it will contribute to scientific literacy and communication. Mark D. Licker Publisher v Contents Preface ................................................................................................................. v Staff ...................................................................................................................... vi How to Use the Dictionary ........................................................................... vii Fields and Their Scope .................................................................................