David London

Experimental Geochemistry, Mineralogy, Igneous and Metamorphic Petrology, Economic Geology of Metals

Research

My research pertains to the origin and chemical evolution of felsic magmas that solidify as granites, pegmatites, and rhyolites, and to the properties of crystalline and melt phases that promote the transfer of volatile and lithophile trace elements from deep to shallow crustal reservoirs. To date, we have utilized field and analytical methods, plus made extensive use of my experimental lab at OU, to assess the abundance and behavior of H2O, fluorine, boron, and phosphorus, rare alkalis and alkaline earths (Li, Rb, Cs, Be, Sr, Ba) and high field-strength elements (Nb, Sn, Ta) in these magmas. We have mapped out the geochemical cycles of these elements from aluminous migmatite sources, through granite differentiation, to end-stage pegmatites and other granite-associated ore deposits. This work proceeds in an iterative fashion between field and experimental lab studies to develop models or to test hypotheses for the derivation and fractionation of these silicic magmas.

From the combination of field and experimental work, I have formulated a model for the origin and internal differentiation of granitic pegmatites that successfully integrates observed chemical trends with crystal fabric and mineral zonation. Much work remains in the correlation of the model with natural pegmatites, however. My current research, and directions for future study to hone the model, are described on my pegmatite web page at: http://pegmatopia.ou.edu The purpose of this site is to describe the opportunities for pegmatite-related research for prospective graduate students at OU. If you are interested in pegmatites, or the experimental side of our work, then please visit PEGMATOPIA to learn more. I am also chair of and manage an international body of professional and amateur scientists, mineral collectors, and others interested in the mineralogy and petrology of pegmatites. We are the Pegmatite Interest Group, or PIG for short. The "PIG pen" is hosted by the Mineralogical Society of America at: http://www.minsocam.org/msa/special/Pig/ The PIG site presents short articles on pegmatites, and news of pegmatites and pegmatite minerals, MUCH more quickly than these appear in publications. There is also a question & answer section that hosts considerable activity, and "Best Shots" of photos related to pegmatites.

I supervise the School's laboratories for experimental petrology and fluid inclusion analysis, and am in charge of the School's mineral collections. I am also the director of the University's electron microprobe laboratory.

Teaching

My undergraduate courses have included Physical Geology; Gold, Silver, and Gemstones; Introduction to Mineral Sciences; Igneous and Metamorphic Petrology. Graduate courses have included Metamorphic Petrology; Economic Geology of Metallic Ore Deposits; and other courses on specific aspects of experimental geochemistry, fluid inclusion analysis, and granite systems.

Students and Visiting Scientists

Graduate instruction in hard-rock disciplines at OU is mostly tutorial in nature and is customized to the interests and needs of the student. My graduate students also learn from group interactions that are both formal (weekly meetings) and informal instruction in the labs and field. For the M.S. degree, I recommend that the thesis have some component of field study, even if only sample collecting and analysis, to give meaning and context to the more abstract work that follows. A student might take a field/analytical study for the M.S. degree on to an experimental program for the Ph.D. For the Ph.D., the geologic training comes mostly from research in my working group. I advise Ph.D. candidates to obtain a minor area of specialization in another discipline, such as chemistry, mathematics, engineering, etc. I also encourage graduate students to obtain some training in small business administration as the basis for creating and running their own companies.

Where Are They Now?

Kathleen S. Goodman (M.S. 1986) principal geoscientist, Enviros, Seattle, WA
George B. Morgan VI (M.S., 1986, Ph.D. 1988) Research Scientist II and Adjunct Associate Professor, University of Oklahoma
Jonathan P. Icenhower (Ph.D. 1995) Group geochemistry leader, Battelle Corporation, Pacific Northwest National Laboratory, Richland, WA
Michael B. Wolf (Visiting Scientist, 1992-1995) Associate Professor, Augustana College, Rock Island, IL
Joseph M. Evensen (Ph.D. 2001) Research Scientist, Shell International Exploration and Development, Houston, TX
Eric A. Fritz (M.S. 2001) Gem Research Laboratory, Gemological Institute of America, Carlsbad, CA
Antonio Acosta-Vigil (Visiting Scientist, 1998-2004) Faculty of Geoscience Research, University of Granada, Spain

Current Projects for Prospective Students

My students and visiting scientists have engaged in work closely related to my own, so that we function as a group. The notion of group activity is pervasive, and we all share in the dialogue and research leading to solutions. One group activity just beginning will entail detailed petrographic, mineral- chemical, and isotopic analysis across complete (sawed & polished) sections of zoned pegmatite dikes. Working as a group, we will be the first to generate such complete data sets across zoned pegmatite dikes, and we will use these natural samples to evaluate our experimentally based models. Other experimental projects study the interactions of crystals and melts as applied to some basic questions of igneous petrology: how do melt compositions change as crystals dissolve, and how do melt compositions change as crystals grow? A third experimental program involves the formation of metallic ore deposits in granites, and serves as a test of long-held assumptions about specific associations of metals and complexing agents.

Field areas include localities of granites, pegmatites, and migmatitic metamorphic rocks in California, Connecticut, Canada, England, and Spain.

Current funding in support of my research, including stipends for graduate research assistants, is provided through grants from the National Science Foundation, the U.S. Department of Energy, and University sources.

Snap Shots

[Click on images to view larger]

Selected Recent Publications

1. London, D., Ertl, A., Hughes, J.M., Morgan VI, G.B., Fritz*, E.A., and Harms*, B.S. (2006) Synthetic Ag-rich tourmaline: structure and chemistry. American Mineralogist, 91, 680-684.

2. Acosta-Vigil#, A., London, D., and Morgan, G.B. VI (2006) Experimental partial melting of a leucogranite at 200 MPa H2O and 690-800oC: compositional variability of melts during the onset of H2O-saturated crustal anatexis. Contributions to Mineralogy and Petrology, 151, 539-557.

3. Acosta-Vigil#, A., London, D., Morgan, G.B., VI, and Dewers, T.A. (2006) Dissolution of quartz, albite, and orthoclase in H2O-saturated haplogranitic melt at 800°C and 200 MPa: diffusive transport properties of granitic melts at crustal anatectic conditions. Journal of Petrology, 47, 231-254.

4. London, D. (2005) Geochemistry of Alkalis and Alkaline Earths in Ore-Forming Granites, Pegmatites, and Rhyolites. Invited chapter for “Rare-element geochemistry of ore deposits” (Linnen, R. and I. Sampson, eds.). Geological Association of Canada Short Course Handbook, 17, 17-43.

5. Cerný, P., Blevin, P.L., Cuney, M., and London, D. (2005) Granite-related ore deposits. Economic Geology, 100th Anniversary Volume, 337 - 370.

6. Morgan, G.B. VI and London, D. (2005) Phosphorus distribution between potassic alkali feldspar and metaluminous haplogrnaite liquid at 200 MPa (H2O): the effect of undercooling on crystal-liquid systematics. Contributions to Mineralogy and Petrology, 150, 456-471.

7. Morgan, G.B. VI and London, D. (2005) Effect of current density on the electron microprobe analysis of alkali aluminosilicate glasses. American Mineralogist, 90, 1131-1138.

8. Acosta-Vigil#, A., London, D., and Morgan, G.B., VI (2005) Contrasting interactions of sodium and potassium with H2O in haplogranitic liquids and glasses at 200 MPa from hydration-diffusion experiments. Contributions to Mineralogy and Petrology, 149, 276-287.

9. London, D. (2005) Granitic pegmatites: an assessment of current concepts and directions for the future. Invited contribution to: “Granitic Systems – State of the Art and Future Avenues” (O.T. Rämö, P.J. Kosunen, L.S. Lauri, and J.A. Karhu, eds), an issue honoring the retirement of Prof. Ilmari Haapala, University of Helsinki. Lithos, 80, 281-303.

10. Acosta-Vigil#, A., London, D., Morgan, G.B. VI, and Dewers, T.A. (2003) Solubility of excess aluminum in hydrous granitic melts in equilibrium with peraluminous minerals at 700-800°C and 200 MPa: significance and applications of the aluminum saturation index. Contributions to Mineralogy and Petrology, 146, 100-119.

11. Morgan, G.B. VI and London, D. (2003) Trace element partitioning at conditions far from equilibrium: Ba and Cs distributions between alkali feldspar and undercooled hydrous granitic liquid at 200 MPa. Contributions to Mineralogy and Petrology, 144, 722-738.

12. Evensen*, J.E. and London, D. (2003) Experimental partitioning of Be and other trace elements between cordierite and silicic melt, and the chemical signature of S-type granite. Contributions to Mineralogy and Petrology, 144, 739-757.

13. London, D. and Evensen*, J.M. (2003) Beryllium in silicic magmas and the origin of beryl-bearing pegmatites. Invited chapter for Beryllium: mineralogy, petrology, and geochemistry (E.S. Grew, ed.). Mineralogical Society of America Reviews in Mineralogy & Geochemistry, 50, 445-486.

14. Acosta-Vigil#, A., London, D., Dewers, T.A., and Morgan, G.B. VI (2002) Dissolution of corundum and andalusite in H2O-saturated haplogranitic melts at 800ºC and 200 MPa: constraints on diffusivities and the generation of peraluminous melts. Journal of Petrology, 43, 1885-1908.

15. Evensen J.M*. and London, D. (2002) Experimental silicate mineral/melt partition coefficients for beryllium, and the beryllium cycle from migmatite to pegmatite. Geochimica Cosmochimica Acta, 66, 2239-2265.

16. London, D., Morgan, G.B. VI, and Wolf, M.B. (2001) Amblygonite-montebrasite solid solutions as monitors of fluorine in evolved granitic and pegmatitic melts. American Mineralogist, 86, 225-233.

* Student; # Post-doctoral Visiting Scientist