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Introduction: A tribute to Hatten S. Yoder, Jr. on his 80th birthday

BJORN MYSEN

Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., W, Washington D. C 20015, USA

This Special Issue has been prepared to mark the 80th birthdayof Hatten S. Yoder, Jr. The authors of the individual papersrepresent but a small fraction of all those whose careers havebeen touched and influenced by Hat’s own 54-year researchcareer.

The impact of Hat’s research on our understanding of thephysicochemical principles that control rock-forming processesis a direct consequence of his wide range of interests andresearch activities, including phase equilibria in silicate andsulfide systems, properties of minerals and melts at high pres-sure, hydrothermal mineral synthesis, energy transfer in par-tially molten systems, and abiotic synthesis of organic com-pounds. There is hardly a topic in modern experimentalpetrology and geochemistry where we cannot find that he hasbeen involved and often led the way. Of course, none of thiswould have been possible were it not for his enthusiasm,energy, and willingness to share his thoughts with those aroundhim. The published record does not, however, reflect his earliercareer as a meteorologist in the U. S. Navy during World WarII nor his stint as a semiprofessional trombonist in Chicago tosupport himself while a student.

The focus of Hat’s scientific career, whether his early studieson the high-pressure stability of jadeite, stability relations ofmicas, sulfide mineral stabilities, or his most recent activitiesassociated with organic geochemistry, has been experimenta-tion in the laboratory at high pressure and high temperature. Alogical venue for such research was, and is, the GeophysicalLaboratory, where high-temperature experimental studies al-ways have been a central endeavor.

Hat joined the scientific staff at the Geophysical Laboratoryin 1948, served as its director from 1971 until 1986, and hasworked here as an emeritus ever since. The transition to emer-itus status did not, however, slow Hat down. Before Hat’sarrival at the Geophysical Laboratory, high-pressure experi-ments were limited by instrumental constraints to the upper-most portions of the Earth’s crust. Therefore, upon arriving in1948, Hat set out to design an apparatus capable of reaching thepressure and temperature conditions of the deep crust and uppermantle. The resulting apparatus, the internally-heated, high-pressure apparatus, is still in use.

Hat’s early work on jadeite stability relations and on theeffect of pressure on the melting point of diopside took fulladvantage of the new apparatus. Those studies were soonfollowed by several experimental investigations on the stabilityrelations of micas. The interest in mica stability relations cul-minated with a detailed investigation of the melting relations ofphlogopite in the pressure range of the crust and the uppermantle of the Earth. An important result of that investigationwas that a hydrous mineral such as phlogopite was stable atupper mantle pressures to its melting point. Hat established,

therefore, more than 40 years ago, that phlogopite could be aprincipal mineral in which H2O could be recycled from near theEarth’s surface and its crust into the interior of the Earth. Thestudy on phlogopite stability also provided the principles thatgovern melting relations of other hydrous minerals at highpressure.

Perhaps inspired by giants such as Normal L. Bowen andFrank Schairer, characterization of high-pressure and high-temperature stability relations of minerals quickly led Hat tofocus on melting relationships among silicates. This interest isreflected in a number of simple-system experimental studiespublished in the Fifties. Those, in turn, led to a major study onthe origin of basalt magmas, a 190-page article published in theJournal of Petrology. It was here that the now-classic basalttetrahedron first saw the light of day. The phase relations withinthe basalt tetrahedron remain the guiding light for anyoneinterested in basalt petrogenesis to this day.

HATTEN S. YODER, JR.

Pergamon

Geochimica et Cosmochimica Acta, Vol. 66, No. 12, pp. 2071–2072, 2002Copyright © 2002 Elsevier Science LtdPrinted in the USA. All rights reserved

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2071

The central theme of Hat Yoder’s career as an experimen-talist always has been that if an experimental protocol could bedesigned to illuminate a problem, he would go ahead and do theexperiments. If he could not do them himself, he would findsomebody who could. As Hat’s colleagues, we have often been

on the receiving end of his many ideas and suggestions. Forthose of us who have had the pleasure of Hat’s inspiringpresence, we expect this to continue.

This Special Issue marking Hat’s 80th birthday certainly willnot mark the end of a long career, but simply a milestone.

2072 B. Mysen