This third edition of the Glossary of Geology contains approximately 37,000 terms, or 1,000 more than the second edition, as well as 650 emendations and corrections. In addition, it includes for the first time the division of cited terms in syllables, with accents to aid in pronunciation. Approximately 150 references have been added to the 2,000 in the second edition. Literature cited ranges from the early 1790s to 1986. New entries are especially numerous in the fields of carbonate sedimentology, hydrogeology, marine geology, mineralogy, ore deposits, plate tectonics, snow and ice, and stratigraphic nomenclature. Many of the definitions provide background information. Thus the reader will learn the difference between sylvanite and sylvinite, and many other look-alike pairs; the origin of such terms as charnockite and lottal; the meaning of BHP, LVL, MORB, and more than 100 other abbreviations now common in the geoscience vocabulary; and the dates when many terms were first used, the meaning of certain common prefixes, and the preferred term of two or more synonyms.The authority of this new edition - like that of its predecessors - rests on the expertise of geoscientists from many specialties, who have reviewed definitions, added new terms, and cited references. Their contributions make the Glossary an essential reference work for all in the geoscience community. Printed on recycled, acid-free paper.