Julia Eve Hammer

I use field, analytical, and experimental methods to study magmas as they accumulate in crustal storage regions, mix and equilibrate with other magmas, and ascend to the surface during volcanic eruptions. I am interested in constraining and utilizing the differences in the rates of magmatic processes in order to better understand subsurface plumbing systems and transport processes. Toward this goal, I am building an experimental petrology laboratory that will be capable of studying geologic materials at high temperatures (600- 1700 ^oC) and at pressures corresponding to a depth range in the Earth's crust of 0- 12 km (1 bar to 4 kbar).

Publications

Shamberger, PJ and Hammer, JE (submitted) Leucocratic and Gabbroic Xenoliths from Hualalai Volcano, Hawaiπi. J. Petrology

Hammer, JE, M Coombs, PJ Shamberger, J Kimura (in press) Dynamic Submarine Flanks of Hualalai Volcano, Hawaii. J. Volcanol. Geotherm. Res. download pdf

Hammer, JE (in press) Influence of fO₂ and cooling rate on the kinetics and energetics of Fe-rich basalt crystallization. Earth Planet. Sci. Lett.

Hammer, JE (2006) Interpreting Inclusive Evidence. Nature 439: 26-27. download pdf

Hammer, JE (2004) Crystal nucleation theory applied to hydrous magma. Am. Mineral. 89: 1673-1679. download pdf

Hammer, JE and Rutherford, MJ (2003) Petrologic Indicators of pre-eruption magma dynamics. Geology 31: 79-82. download pdf

Hammer, JE, MJ Rutherford, and W Hildreth (2002) Storage conditions of intermediate magmas prior to the 1912 eruption in the Valley of Ten Thousand Smokes, Alaska. Contrib. Mineral. Petrol.144: 144-162. download pdf

Hammer, JE, and Rutherford,MJ (2002) An experimental study of decompression-induced crystallization in silicic melt. J. Geophys. Res. 107(B1), 8-1 - 8-24. download pdf

Hammer, JE, Cashman, KV, Voight, B. (2000) Magmatic processes revealed by textural and compositional trends in Merapi dome lavas. J. Volcanol. Geotherm. Res. 100: 165-192. download pdf

Hammer, JE, Cashman, KV, Hoblitt, R.P., Newman, S. (1999) Degassing and microlite crystallization during pre-climactic events of the 1991 eruption of Mt. Pinatubo, Philippines Bull Volcanol, 60: 355-380. download pdf

Hammer, JE, Manga, M, Cashman, KV (1998) Non-equilibrium and unsteady fluid degassing during slow decompression. Geophys Res Lett 25: 4565-4568.

Chamberlain, CP, Zeitler, PK, Barnett DE, Winslow, D, Poulson, SR, Leahy, T, and Hammer JE (1995) Active hydrothermal systems during recent uplift of Nanga Parbat, Pakistan Himalaya. J. Geophys. Res. 100 No. B1, 439-453

Recent Abstracts and Presentations

Hammer, JE (2005) Strange Attractors: Symbiosis in Magma Crystallization, Eos Trans. AGU, 86(47).

Brugger, C* and Hammer, JE (2005) Compositional Controls on Melt Polymerization, Eos Trans. AGU, 86(47).

Brachfeld, S and Hammer, JE (2005) Synthetic Fe-rich basalts as Mars analogs: Mineral magnetic and remanence properties, Eos Trans. AGU, 86(47).

Vasquez, J, Shamberger, P*, and Hammer, JE (2005) Timing of extreme magmatic differentiation at Hualalai and Mauna Kea volcanoes from 238U-230Th and U-Pb dating of zircons from plutonic xenoliths, Eos Trans. AGU, 86(47).

Hammer, JE and Rutherford, MJ (2005) Experimental crystallization of Fe-rich basalt: application to cooling rate and oxygen fugacity of Nakhlite MIL-03346. LPSC XXXVI abstract 1999.

Hammer, JE (2004) Rapid, informative crystal texture characterization using surface area to volume measurements. IAVCEI, Chile

Hammer, JE (2004) Crystallization in Hydrous Magmas. Penrose Conference on Neogene-Quaternary Continental Margin Volcanism. Metepec, MX

Hammer, JE (2003) Crystal nucleation theory applied to hydrous magma. Fall AGU.

Hammer, JE and Shamberger, PJ (2003) Dynamic Submarine Flanks of Hualalai Volcano, Hawaii. Fall AGU.

Shamberger, PJ and Hammer, JE (2003) Extreme Magma Differentiation in a Hawaiian Magma Chamber: An Analysis of Gabbro and Syenite Xenoliths from Hualalai Volcano. Fall AGU.

Shamberger, PJ, Hammer, JE, and Coombs, M (2003) Stratigraphy and geochemistry of submarine volcaniclastics in North Kona, Hualalai. Cities on Volcanos 3, Hilo, HI.

Hammer, JE, Brachfeld, S, and Rutherford, MJ (2003) An Igneous Origin for Martian Magnetic Anomalies? Lunar and Planet. Sci. Conf. XXXIV, Houston, TX.

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Graduate Students

Patrick J Shamberger

M.S. candidate, recipient of a National Weather Service Fellowship, a Harold T Stearns Fellowship, a GSA student research grant, and the UH Chancellor's 2004 Outstanding Student in Research Award; graduated Fall 2004

Pat's research involves analysis of xenolith nodules from Hualalai volcano, and interpretation of submarine-collected samples from the North Kona region around Hawaii. Pat is now pursuing a PhD in materials science from the University of Washington.

Carrie R Brugger

MSc. from the Universiity of Oregon 2001, matriculated in the UH PhD program Fall 2004

Carrie is investigating compositional controls on melt structure and the consequences for crystallization kinetics in erupting magmas.

Courses Taught in the Department of Geology and Geophysics

[note: the following syllabi are pdf files that automatically download]

GG 101 Dynamic Earth; syllabus

GG 170 Physical Geology; working syllabus

GG 301 Mineralogy; syllabus

GG 602 Theoretical Petrology; syllabus

GG 710 Magma Chambers and Conduits; syllabus, course evaluation

Current and Recent Projects

Kinetics of Crystallization

1. Study of the crystallization of Fe-rich basalts with application to the origin of magnetic anomalies on Mars

2. Decompression-induced crystallization in rhyolite melt

3. Nucleation data in a theoretical context

Phase equilibrium approaches to determining magmatic pre-eruption conditions

1. Magma differentiation and nature of the plumbing system at Hualalai Volcano, Hawaii

2. Storage of intermediate magmas erupted from Novarupta

3. Pinatubo pre-eruption dynamics

Dynamic submarine flanks of Hawaiian volcanos

1. Submarine sliver in North Kona: A window into the early magmatic and growth history of Hualalai Volcano, Hawaii

Image Galleries

Experimental Petrology Lab

As of spring 2006, all major components of the lab are in place and installation/calibration is nearly complete. Soon it will be possible to study a variety of problems and processes extending from the surface to 10 km into the Earth's crust (considerably deeper in Mars or an asteroid), with pressure conditions that we can vary almost as easily as temperature.

Available facilities:

* One atmosphere CO₂-H₂ gas-mixing furnace (Deltech 1700 ^oC)

* Argon-medium high pressure line for cold seal vessels (TZM/HZM) operating up to 1100 ^oC and 2 kbar, with one rapid quench furnace and one traditional quench furnace

* Water-medium line for cold seal vessels (waspaloy), seven clamshell 1100 ^oC furnaces and plans for 4-5 vertical tube furnaces for rapid-quenching of runs up to 3 kbar

* Pressure variator by Harwood Engineering for automated pressure control (60,000 psi) in the water-medium line

* Mettler 5-place analytical balance

* Olympus BX-51 Pol microscope and Olympus 5050 Zoom digital camera with connected color TV

* Thin sectioning and polishing equipment, including Buehler high-speed saw, and 10" lap wheel, and Vibromet polisher

Hualalai Volcano, Hawaii

Graduate student Pat Shamberger's field work in 2003 on the flanks (Puu Waa Waa pumice cone, Puu Anahulu trachyte flow) and summit (Luamakami) area of Hualalai Volcano

Submersible Study

I was fortunate to participate in leg 1b of the 2002 cruise aboard the RV Yokosuka (JAMSTEC) investigating the submarine flanks of Hawaiian volcanos with chief scientist Eiichi Takahashi (TI Tech, Tokyo). (Several photos are by Michelle Coombs.) Pat Shamberger, Michelle Coombs (USGS Alaskan Volcano Observatory), Jun-Ichi Kimura (Shimane Univ., Matsue, Japan) and I are examining samples collected by the submersible Shinkai 6500 on dives S690 and S692 on the North Kona region of Hualalai Volcano. We are excited by volatile-rich hawaiite lavas that may represent the volcano's pre-shield stage of volcanism.

Magnificent Magnetite

Highlights from an ongoing experimental study with Stefanie Brachfeld (Montclair State University, NJ) examining the effects of cooling rate and oxygen fugacity on texture, liquid line of descent, and magnetic properties.

Feldspar Decompression-Crystallization Textures

Sample back-scattered electron (BSE) images and figures describing experiments wherein Pinatubo dacite was decompressed isothermally from magma reservoir conditions, as described in Hammer and Rutherford (2002)