Director, Electron Microprobe Lab Ph.D. 1989, Johns Hopkins University

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Cameca SX50/51
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------------------------ One of my favorite images is on my card: "Save the Earth Garden". Find out more about it and download a 178 KB copy


(This page is somewhat "old"; more up-to-date information about research is at the Electron Microprobe Lab page

Research Interests and Projects

Volcanic eruptions and early peoples of the Alaska Peninsula:

I am working toward development of a tephrochronology for the Cold Bay region of the Alaska Peninsula, in collaboration with Dave Mickelson and his students Tina Dochat (Ph.D. 1997) and Eric Carson. As many of the tephra layers present here are from Unimak volcanoes to the southwest, proximal tephras from Unimak are important. This project is also tied in with the anthropological research being carried out by H. Maschner (Dept of Anthropology) and associates in the Izembek Lagoon area and on Unimak Island.

Aleutian Volcanic Action
Akutan Volcano 3/96
198 KB image of Akutan

Photo by U.S.G.S.
For more details on active Aleutian volcanoes: Alaska Volcano Observatory

Aleutian arc volcanism:

I have been studying Shishaldin Volcano, one of the largest Aleutian volcanic centers, since 1984. Unlike other Aleutian volcanoes, Shishaldin has erupted a wide range of lavas and pyroclastics -- 3 types of basalts as well as dacite, with apparently little andesite. A major question in arc petrology concerns the significance of high alumina basalts, which generally have abundant plagioclase phenocrysts, and their relation to high magnesian basalts. A variety of tools are used, including major and trace element geochemistry, mineral chemistry, phase equilibria, plus the recently developed crystal size distribution technique.

Shishaldin page with photos

Sulfur-rich Volcanic Eruptions
and Magmatic Anhydrite

Some recent volcanic eruptions have been recognized as having high sulfur contents, which may have significant climatic effects. I have been studying anhydrite-bearing pumices from the 1985 eruption of Nevado del Ruiz (Colombia) and the 1991 eruption of Mt. Pinatubo. As anhydrite phenocrysts rapidly dissolve away after several rainy seasons, the presence of such sulfur-rich eruptions in the geologic record is poorly known. The discovery of anhydrite inclusions within other phenocrysts (e.g., plagioclase, hornblende, or orthopyroxene as shown in this BSE image), however, may provide a valuable clue to discovering past sulfur-rich eruptions. The host minerals for the inclusions can also provide important clues to the pre-eruption magmatic conditions (e.g., pressure, temperature and melt water content).

Magmatic anhydrite page

Courses Taught:

Geology 875-004: Explosive Volcanism, Volcanic Ash, and Tephrochronology Graduate seminar, Spring 1996, for students from Geology, Geography, Soil Science, Anthropology, and Atmospheric Sciences

Syllabus, readings and software

Geology 777: Electron Microprobe Analysis This 2-credit course is taught once a year and provides a theoretical background to an understanding and appreciation of the operation of the electron microprobe. Actual hands-on training for running the SX50 is provided at the time that a user requires it.

Syllabus, readings and software


Fournelle J, Carmody R and Daag A (1996) Anhydrite-bearing Pumices from the June 15, 1991 Eruption of Mount Pinatubo: Geochemistry, Mineralogy, and Petrology, in Fire and Mud: Eruiptions and Lahars from Mount Pinatubo, Philippines, Edited by Newhall and Punongbayan, PHIVOLCS-University of Washington, p. 845-863

Fournelle J, Marsh BD and Myers JD (1994) Age, character and significance of Aleutian Arc Volcanism, in Plafker and Berg (ed) Cordilleran Orogen: Alaska (Volume G-1 of The Decade of North American Geology, published by the Geological Society of America).

Fournelle J and Marsh BD (1991) Shishaldin Volcano: Aleutian high-alumina basalts and the plagioclase accumulation question. Geology 19:234-237.

Fournelle J (1990) Anhydrite in Nevado del Ruiz November 1985 pumice: relevance to the sulfur problem. Journal of Volcanology and Geothermal Research 42:189-201.

UW Electron Microprobe Lab

I run the UW-Madison electron microprobe lab, which consists of a state of the art Cameca SX50 electron microprobe #485 (installed in late 1993), and associated equipment.

John's Picks to Other Home Pages

A plethora of links to other home pages, selected by yours truly


45 Helium Balloons + Lawn Chair = Up UP and AWAY

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