Steve Jacobsen
Department of Earth and Planetary Sciences
Northwestern University
Evanston, IL 60208
Tel 847.467.1825


Biographical Sketch

Steve Jacobsen, Associate Professor of Earth and Planetary Sciences, studies the fundamental role of material properties in various aspects of Earth, planetary, and materials sciences. In mineral physics, he uses high-pressure experiments and information about the composition, structure, and other properties of minerals and melts to understand geophysical processes, geochemical cycling, and to investigate potentially useful properties of minerals and new materials for societal applications. He is especially interested in the origin and distribution of water in the Earth.

Little is known about how much water the Earth contains as a whole, or how the oceans developed. Was Earth's water delivered by comets, or did most of it degass out of the primitive mantle? Jacobsen investigates water in minerals and the role hydrated minerals may play in plate tectonics and the evolution of our planet into a habitable world.

The mineral physics research group at Northwestern works on a wide range of topics, including synthesis of minerals and new materials at extreme conditions, equations of state, composition of the Earth's interior, spectroscopy of volatiles (such as H and C) in minerals, melts, and meteorites, cement mineralogy, elastic properties of materials, and design and synthesis of novel superhard materails. Much of his group's research is carried out at the Advanced Photon Source of Argonne National Laboratory.


This research has been supported by grants from the US National Science Foundation (NSF), awarded through the Geophysics Program and the Petrology and Geochemistry Program (EAR-0440112, EAR-0748707, and EAR-1452344), the Instrumentation and Facilities Program (EAR-0651173, EAR-0948953), and through the Division of Materials Research, Ceramics Program (DMR-1508577). We also use facilities that have been supported by COMPRES, the Consortium for Materials Properties Research in Earth Sciences under NSF Cooperative Agreement EAR 11-57758. Jacobsen's lab is also a partner of the Carnegie/DOE Alliance Center (CDAC), a Stewardship Science Academic Alliances (SSAA) Program of the Department of Energy (DOE). Fellowships have been awarded by the Alexander von Humboldt Foundation and by the David and Lucile Packard Foundation.

Selected Publications

Complete List

Earth's Deep Water Cycle

Steven D. Jacobsen and Suzan van der Lee, Editors

This interdisciplinary volume, available through AGU books, covers research on the origin, distribution, and influence of water in the Earth. High-pressure silicates can incorporate water as OH-defects into their crystal structures, with some major consequences for their physical properties. Minerals within the transition region of the mantle from 410-660 km depth could contain the majority of our planet's water and acted to control surface waters over geologic time.

Could deep geochemical reservoirs of water be detected remotely using seismology? What role has water played in the evolution of plate tectonics and our habitable planet? This volume integrates studies from mineral physics, seismology, experimental petrology, geochemistry, and geodynamics. View the Table of Contents

High-pressure science and technology

In the Northwestern Mineral Physics Laboratory, using gem diamonds as superhard transparent anvils, we simulate conditions found deep inside the Earth and use pressure to modify the structure and physical properties of materials. The diamond anvils, each about 2.5 mm in height, are precisely cut and aligned to support static pressures at their tips in excess of 100 gigapascals (or 1 Mbar, about the pressure 3000 km deep in the Earth). Samples inside are compressed within a tiny sample chamber made by forming a hard, rhenium-metal gasket around the anvil tips. A pressure transmitting medium such as helium surrounds the sample to compress it without being crushed between the diamond tips. The diamonds, transparent to visible, infrared, and X-radiation, allow us to probe the structures and physical properties of materials formed under extreme conditions.

One of the questions we are exploring is how much water the Earth's interior might store deep inside, in the form of OH-defects in high-pressure silicate minerals. The image above right, shows a blue crystal of hydrous ringwoodite (g-Mg2SiO4) at about 30 GPa, just after laser heating to 1600 C (orange spots). By reacting minerals with water under deep mantle conditions, we are studying the hydrogen storage capacity of the mantle, and the influence of OH-related defects on the physical properties of Earth's mantle materials. For example, hydrated silicates of the mantle appear to transmit seismic waves more slowly than dry rock, suggesting that seismology might be used as a remote probe to search for "deep oceans" in the interior.

GHz-ultrasonic interferometry

I am developing a high-frequency acoustic method called gigahertz (GHz) ultrasonic interferometry. This ultrasonic probe has been interfaced with the diamond-anvil cell (DAC) to measure the compressional and shear-wave velocities in single-crystal samples that were previously too small for ultrasonic methods. GHz-frequency shear waves are produced by P-to-S conversion inside a single-crystal gem. Elastic properties of samples as thin as 20 microns have been measured, or about four times thinner than a human hair. The elastic tensor of materials relates stress to strain and is used in mineral physics to understand how seismic waves propagate through the solid Earth. In that sense, we simulate tiny earthquakes in the Northwestern Mineral Physics Laboratory (though at much higher frequency, and shorter wavelengths).

Seismograms from a real earthquake (top) and from inside the diamond-anvil cell.

Professional Interests

Mineral physics and solid-Earth geophysics; geochemistry, geology, planetary science, materials science, condensed matter physics, and physical chemistry, with emphasis on how pressure and temperature modifies fundamental properties of materials such as structure, bonding, and elasticity; Earth’s deep water cycle from atomic to geophysical scales; water in the solar system; extrasolar planets, superhard materials, cement minerals, role of minerals and materials in energy technology; science outreach at all levels.

Courses at Northwestern

EARTH-101: Earth Science for the 21st Century
EARTH-102: The Future of Renewable Energy
EARTH-300: Earth and Planetary Materials
EARTH-301: Petrology: Evolution of Crustal and Mantle Rocks
EARTH-438: Advanced Topics in Geophysics: Water in the Solar System
EARTH-438: Advanced Topics in Geophysics: Mineral Physics From Crust to Core
EARTH-440: Advanced Topics in Geochemistry: Metamorphic and Sedimentary Petrology


2014 Bessel Award, Alexander von Humboldt Foundation
2013 Distinguished Teaching Award, Weinberg College of Arts and Sciences, Northwestern University
2008 Presidential Early Career Award for Scientists and Engineers (PECASE), see a photo
2008 Packard Fellowship for Science and Engineering, David and Lucile Packard Foundation
2008 Faculty Early Career Development Award, National Science Foundation
2007 Mineralogical Society of America Distinguished Lecturer
2005 Barbara McClintock Fellowship, Carnegie Institution of Washington
2002 Alexander von Humboldt Fellowship, Bayerisches Geoinstitut


Ph.D. Geophysics; University of Colorado
B.A. Geology,; University of Colorado

Positions Held

Associate Professor, 2011-present
Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL

Assistant Professor, 2006-2011
Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL

Research Scientist (Principal Investigator), 2005-2006
Carnegie Institution of Washington, Geophysical Laboratory, Washington D.C.

Barbara McClintock Fellow; 2005
Carnegie Institution of Washington, Geophysical Laboratory, Washington D.C.

Alexander von Humboldt Fellow and Research Associate, 2002-2004
Bayerisches Geoinstitut, University of Bayreuth, Germany

CIRES Graduate Research Fellow, 1999-2000
Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Geological Sciences, University of Colorado


My favorite rock shop: Dave's Down to Earth Rock Shop.

RRUFF Project: Database of Raman spectra, X-ray diffraction, and chemical data for minerals.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.