Experimental and geochemical studies of terrestrial and lunar magmatic processes by Thomas Paul Wagner B.S. Geology, Binghamton University, 1989 Submitted to the Department of Earth, Atmospheric and Planetary Sciences in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in Geology at the Massachusetts Institute of Technology May 1995 © Massachusetts Institute of Technology All rights reserved /- / Signature of author Department of Earth, Atmdpheric and Planetary Sciences I A Certified by - Professor Timothy Grove Thesis Supervisor Accepted by Professor Thomas Jordan Department Head MASSACHIJSETS INSTITUTE OF TFCNJOLOGY JUN 0 51995 LIBRARIES 1 , ndgre 2 Experimental and geochemical studies of terrestrial and lunar magmatic processes by Thomas Paul Wagner Submitted to the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology on May 26, 1995 in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geology Abstract Experimental and geochemical studies were performed to understand the formation of certain terrestrial and lunar igneous rocks. Chapter one is a study of convergent margin magmatism at Medicine Lake Volcano, California. The petrogenesis of a suite of variably porphyritic, high-alumina lavas was inferred from field relations, hydrous melting experiments and geochemical modeling. I conclude that phenocryst-poor lavas formed by hydrous differentiation, while phenocryst-rich lavas formed by a combination of hydrous differentiation and crystal accumulation. Chapters two and three discuss the origin of oceanic island tholeiite at Kilauea volcano, Hawaii. Chapter two reports the results of phase equilibria experiments on an estimated tholeiite primary magma. The results show that tholeiite primary magmas are in equilibrium with depleted harzburgite at lithospheric depths beneath Hawaii. I propose that Hawaiian tholeiite forms by melting of garnet lherzolite in deep parts of a mantle plume and that these melts equilibrate with depleted harzburgite in the plume top. Chapter three is an ion-microprobe study of picritic glass grains from Kilauea volcano, Hawaii. These glasses have the highest MgO-contents of any glass found in Hawaii and were used to make the primary magma estimate studied in chapter two. The glasses have trace element abundances similar to other Hawaiian lavas and show variation consistent with derivation by partial melting of garnet lherzolite. Chapter four models the origin of lunar high-Ti magmas using the results of two experimental studies. First, the phase relations of the most Ti-rich lunar ultramafic glass, Apollo 14 black glass, were determined to 2.5-GPa. Second, the dissolution rate of ilmenite was measured in both high- and low-Ti lunar magmas. The experimental results support the generation of the high-Ti lunar ultramafic glasses by assimilation of ilmenite and clinopyroxene into low-Ti primary magmas. This model allows the generation of high-Ti lunar magmas without overturn of the lunar mantle. The thesis also contains two appendices that discuss the construction and calibration of the piston-cylinder device used to perform the experiments. Thesis Supervisor: Dr. Timothy L. Grove, Professor of Geology 4 Acknowledgments: Many people have contributed to my education and the completion of this thesis. First and foremost among those is Tim Grove, my mentor and friend, who put an exceptional amount of time and energy into teaching me about igneous rocks. Tim provides a very stimulating environment to work in by constantly pushing students to try new things and allowing us the freedom to explore any area we choose to work in. Fred Frey was always willing to discuss my work and his help enabled me to work on Hawaiian volcanism. Fred's 'Trace Element Geochemistry' course was one of the most important classes I have ever taken. Aside from the knowledge I gained, it was the place I learned to read and understand scientific papers. Rosamond Kinzler deserves a small monument for selflessly giving of her time. Ro taught me most of the techniques used in this thesis. Glenn Gaetani has been a great officemate and has provided thoughtful insight into all of my work. Alberto 'Bandito' Saal, Eiichi '5' Takazawa and Huai-Jen 'Wyman' Yang have continually helped me through discussion, reading of manuscripts and aiding in research. Steve Recca, Mike Jercinovic, and Nilanjan Chatterjee expertly maintained the MIT electron microprobe and contributed to these works through discussion of the analytical technique, as well as reviewing abstracts and manuscripts. Steve helped me write my first general exam paper by placing a pen in my hand, putting a pad in front of me and ordering me to write! Julie Donnelly-Nolan and Tom Sisson were instrumental in the completion of chapter one. Julie provided the samples, patiently explained the field relations and helped me rewrite the manuscript. Tom trained me in the experimental technique and intensively reviewed the manuscript. Discussions with Ro Kinzler greatly aided the development of the melting models in chapter two. Ro and Mike Walter generously allowed me to use their unpublished data on the composition of garnet lherzolite melts. David Clague provided the samples studied in chapter three, reviewed the manuscript and has given me a number of lessons on Hawaiian volcanism. Erik Hauri has become a good friend and collaborator on a number of projects, including chapters two and three. Even when busy moving from WHOI to DTM, Erik made time to help me on the ion-probe. Brian Evans and Nobu Shimizu served on my thesis committee and provided thought provoking discussions of my research. It was a pleasure talking with Nobu about the importance of the contribution of geoscience to society. Peter Kelemen's talks on melt/wall rock reaction given during the Keck Geodynamics seminar at WHOI inspired the assimilation models developed for both the Hawaiian and Lunar chapters. Discussions with Henry Dick and others during that seminar and its field trips were very valuable educational experiences. MIT colleagues and friends Drew Coleman, Beverly Saylor, Karen Bartels, Tom Juster, Alan Brandon and the Reverend Billy Jones helped in ways too numerous to list. Thanks also go to Derek Hirst, who machined many exact things from my inexact drawings and Karen Campbell who cheerfully provided critical assistance in library research. I've made a lot of great friends at MIT outside of EAPS who in no small part helped me finish. Special thanks go to the MIT men's and women's Rugby football clubs for great times and helping to keep me sane in the early years. I'd especially like to thank my housemates: Jon 'Dingo' Suber, Inpachelvan 'Chevy' Vithianithan, T.J. Craddick, and other rugby friends: Rachael Berman, Brigette Tannian, Eik, Stracher, EMO, Elmo, Paul, Killer, Leo, Greg T., Jaco, Fife, Hoss, Kiwi, Hyena, Ben Paul, Murph, Jeff, Pat M., Brian T., Jim Culliton, and the most inspirational leader I have ever met, Marthinus 'Tienie' van Schoor. I'd also like to thank all the students of D-Entry, MacGregor House for their friendship and for making graduate school a lot of fun! I wish I could list everybody, but in particular I want to thank: Leslie 'in-charge' Compton, Becky 'CEO- bound' Foster, John 'Control-Freak' Robinson, Art 'Prince of Cambridge' Min, Tan 'Gunjan' Bhatnagar, Vince 'Big-Mouth' Rose, Hemant 'Haji-Jordan' Taneja, Anand 'is a- nal' Radhakrishnan, Jon '2-tall' Hsiao, Dave 'Twitcher' Hully, Brian 'Baden Powell' Blatnik, Brian 'Rainbow Head' Zabel, Adel 'Rikers bound' Rophaiel, Diana 'Banana' Chiang, Zvonimir 'Z' Turcinov, Pratip 'the double E in Geek' Banerji, Mark 'Jedhi' Ribick, Maggie 'Betty Crocker' Raphael and last but not least, Brad Spiers, the most intense human being on earth and my personal career counseler. Thanks also go out to other MITers: Lynn Roberson, one of the most interesting people to discuss the meaning of life with I've ever met; Dave Custer, who has recently been teaching me about both writing and rock climbing; and Megan Jasek who commiserated with me on finishing a thesis! My professors and friends at SUNY Binghamton turned me on to geology and encouraged me to go on. Tim Lowenstein, through his outstanding course, Introduction to Geologic Processes, inspired myself and many other fortunate undergraduates to study geology. Great classes and discussions were also had with Bob Demicco, Dick Naslund, Dave Jenkins, Bill MacDonald, Erik Johnson, Julieanne Turko and Jim Kradyna. Important thanks go to all my classmates, including: Dave Winslow, Sara Marcus, Jen Montieth, and Becky Soble. We had a lot of fun and learned a lot together. I'd also like to thank Bernadette Kamin, Dan Abernethy and Kevin and Nancy Nazca for encouragement along the way. Some of the most important skills I used in performing this research I learned while working at Engelbosch bicycles with Mr. Charles Sulc, who was also my most excellent high school geometry teacher. Thank you Chuck! I'd like to thank all the teachers I've ever had, and in particular: Mr. Case, who taught us that learning was fun; Ms. Diane Yaris who started science-oriented extracurricular activities including the 'learn-at-lunch' computer course and the 'Robotics and Electronics' course; Mr. Rizzi, who combined learning the Spanish language with an intensive literature appreciation course; Mr. Danley, whose european history class was so well taught I still think of it often; Mr. Griffith, my engine mechanics teacher