Acceptance speech for F. W. Clarke Medal

Abstract

Thanks for the kind introduction and let me say I feel it a very great honor to be chosen to be here today. There are many persons without whose aid I would not be standing before you today. Foremost among these are my colleagues at Harvard, especially John Longhi and Jim Hays who have collaborated in and considerably improved any contributions I may have made. I feel that they are as much a part of this honor as I am. I would also Iike to thank those responsible for carrying out the Apollo program who provided this marvelous legacy of planetary samples on which we have been fortunate enough to work. Surely the return of these samples must be considered a triumph of initiative and imagination. Finally I would like to thank my wife Sandy for her years of pleasant patience while I puttered in the lab. They helped a lot. 1 should hasten to add that there was no small element of luck in any progress that we may have made. There are at least two important aspects to this luck. First is that for a beginner in the experimental petrology game it was extremely fortunate that the lunar basaltic compositions proved to be relatively tractable experimentally, owing to their volatiledepleted character. Also their compositional variation was amenable to graphic analysis with simplified phase diagrams. It could easily have turned out otherwise but luckily it did not. Secondly, in the context of a whole new planet offered for study, there was a relative minimum of previous prejudicial experience. For the beginner those two circumstances must be considered happy indeed! f would like to offer you a brief historical perspective on thoughts concerning basalt petrogenesis which, of course, is the main field of my interests. I do this not only to amplify the latter circumstance I have just noted, but also to point out some interesting parallels between terrestrial and lunar petrogenetic ttlinking because I feel there are some. Although there are distinct parallels in the thinking, the time scale for terrestrial basalt ideas of about 200 years is telescoped into the last few years for the lunar basalts. At least three ‘vintages’ of thought are worth exptoring for parallelisms. TWO hundred years ago the question was: are basal% the product of fire or of water?-the old Neptunist-Vulcanist controversy, resolved in favor of the Vulcanists. Now I may perhaps be straining a point, but I remind you that water was once thought to be responsible for the lunar maria-as their name implies. Indeed it would be quite irresponsible of me to have you believe that a major achievement of the Apollo program has been to resolve this point for