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Dr. James H. Wittke

Title:  Geologic Materials Analyst
Degree: Ph.D., The University of Texas at Austin
Specialty:  Igneous Petrology, Meteoritics, Cosmochemistry

Research Interests: I supervise the operations of the electron microprobe laboratory, which houses a Cameca MBX microprobe and the Northern Arizona Meteorite Laboratory (with Ted Bunch). My research interests focus upon petrologic problems ranging from terrestrial igneous rocks to meteorites.

Recently, I have been part of an international team of researchers that have proposed an impact of a comet or low-density asteroid was the cause of the Lower Dryas Cooling, associated megafaunal extinctions, and demise of the Clovis Culture. Here is a link to the publication in the Proceedings of the National Academy of Sciences.

Colorized scanning electron microscope image of a reticulated glassy carbon sphere from the Lower Dryas boundary layer.

Recent Publications (2007)

R. B. Firestone, A. West, J. P. Kennett, L. Becker, T. E. Bunch, Z. S. Revay, P. H. Schultz, T. Belgya, D. J. Kennett, J. M. Erlandson, O. J. Dickenson, A. C. Goodyear, R. S. Harris, G. A. Howard, J. B. Kloosterman, P. Lechler, P. A. Mayewski, J. Montgomery, R. Poreda, T. Darrah, S. S. Que Hee, A. R. Smith, A. Stich, W. Topping, J. H. Wittke, & W. S. Wolbach, 2007, Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling. Proceedings of the National Academy of Science, 10.1073/pnas.0706977104.

J. H. Wittke, T. E. Bunch, A. West & R. S. Harris, 2007, Melt spherules from Peter's Pond, a Carolina Bay, South Carolina. Meteoritics & Planetary Science, Vol. 42, Supplement, Proceedings of 70th Annual Meeting of the Meteoritical Society, held August 13-17, 2007 in Tucson, Arizona, #5249.

T. E. Bunch, A. J. Irving, J. H. Wittke, S. M Kuehner, M. Gellissen, H. Palme, D. Rumble, III & D. A. Gregory, 2007, Petrology and bulk composition of CH3 chondrite Northwest Africa 2210. Meteoritics & Planetary Science, Vol. 42, Supplement, Proceedings of 70th Annual Meeting of the Meteoritical Society, held August 13-17, 2007 in Tucson, Arizona, #5132.

T. E. Bunch, A. J. Irving, J. H. Wittke, S. M. Kuehner, D. Rumble, 2007, Distinctive Magnesian, Protogranular and Polymict Diogenites from Northwest Africa, Oman and United Arab Emirates. Meteoritics & Planetary Science, Vol. 42, Supplement, Proceedings of 70th Annual Meeting of the Meteoritical Society, held August 13-17, 2007 in Tucson, Arizona, #5133.

T. E. Bunch,  A. J. Irving,  J. H. Wittke,  D. Rumble, III & A. A. Aaronson, 2007, Northwest Africa 2993: A coarse-grained lodran-like meteorite with affinities to Winoaites. 38th Lunar and Planetary Science Conference, paper 2211.

G. Ozinski, T. E. Bunch, A. Kearsley, and J. H. Wittke, Shocking carbonates at Meteor Crater, Arizona. Submitted to Geology, May 2007.

J. Irving, T. E. Bunch, J. H. Wittke, S. M. Kuehner & D. Rumble, 2007, III Assessment of multi-component mixing, oxidation, metamorphism and parental melting on the acapulcoite-lodranite parent body, 38th Lunar and Planetary Science Conference, paper 2254.

J. H. Wittke, T. E. Bunch & C. A. Goodrich, 2007, Classification of secondary reduction textures in ureilites. Meteoritics & Planetary Science, Vol. 42, Supplement, Proceedings of 70th Annual Meeting of the Meteoritical Society, held August 13-17, 2007 in Tucson, Arizona, #5246.

G. R. Osinski, T. E. Bunch & J. Wittke, 2007, Impact Melt Generation At Meteor Crater, Arizona: Implications For Impacts Into Volatile-Rich Target Rocks. Meteoritics & Planetary Science, Vol. 42, Supplement, Proceedings of 70th Annual Meeting of the Meteoritical Society, held August 13-17, 2007 in Tucson, Arizona, #5110.