Academic Personnel Emeriti

Cathy BusbyCathy J. Busby
Professor Emerita
Ph.D., Princeton University (1983)
1125 Earth & Physical Sci
Structural Geology and TectonicsEarth-Surface ProcessesPaleoclimate and Paleoenvironmental Change; Igneous and Metamorphic Petrology

A first-generation college student, Professor Busby got her B.S. degree from UC Berkeley (1976), her Ph.D. at Princeton University (1983), and was a faculty member at UC Santa Barbara for 32 years. She raised three daughters, who all graduated from the University of California. Cathy moved to UC Davis in January 2015 as Professor Emerita and Research Scientist because the Earth and Planetary Sciences department has a high proportion of female faculty and is very supportive of women. Her current research is on late Cenozoic transtensional rift tectonics and volcanology of the Sierra Nevada/Walker Lane and the Gulf of California, as well as an accreted oceanic arc terrane in Baja California, with comparisons to modern oceanic arcs. Cathy’s research is based on detailed geologic mapping of volcanic terranes, supported by petrographic, geochemical, geochronological, paleomagnetic and mineral chemistry data. | Google Scholar profile

Richard CowenRichard Cowen
Senior Lecturer Emeritus
Ph.D., Cambridge (1966)
richard "at"

Functional and anatomical reconstruction of fossil invertebrates; the interrelationship between geology and people. Projects include work on trilobite eyes, algal symbiosis in fossils, and analysis of the human impact of a historic earthquake in the area.

Howard DayHoward W. Day
Professor Emeritus
Ph.D., Brown (1971)
2234 Earth & Physical Sci | 530-752-2882
Igneous and Metamorphic Petrology

Professor Day’s research interests are in the broad field of igneous and metamorphic petrology and geochronology with significant emphasis on thermodynamics and phase equilibria and applications to understanding the evolution of orogenic belts. Most of his work has been in the Sierra Nevada of California but also includes contributions to the metamorphic petrology and geochronology of the California Coast Ranges, the New England Appalachians, and the Qinling and Tianshan orogenic belts of China. Continuing projects involve the structure and metamorphism of Mesozoic volcanic arc terranes in the Sierra Nevada foothills. Currently, he is studying the geochronology and petrology of high-grade exotic blocks in Franciscan mélange in the California Coastal Range. Google scholar profile | ORCID

John DeweyJohn F. Dewey
Distinguished Professor Emeritus
Ph.D., University of London (1960)
Structural Geology and Tectonics

Basic interests and knowledge are in structural geology and tectonics from the small-scale materials science of deformed rocks to the large-scale origin of topography and structures. Ongoing field-based research is on the rock fabrics and structures of transpression and transtension especially in California, New Zealand, Norway, Ireland and Newfoundland. Evolving interests are in the neotectonics of California and Nevada in the relationship among faulting,topography, and sediment provenance, yield and distribution. Derivative interests are in the geohazard of volcanoes, earthquakes and landslides.

Jim DoyleJames A. Doyle
Professor Emeritus
Ph.D., Harvard University (1971)
5349 Storer Hall | 530-752-7591

Professor Doyle's research deals primarily with the origin and early evolution of angiosperms. His oldest interest is in Cretaceous fossil pollen and leaves and their implications for the evolution, geographic spread, and original ecology of angiosperms. More recently his research has emphasized phylogenetic analyses of relationships between angiosperms and other seed plants and among living primitive angiosperm groups, based on morphological, molecular, and fossil evidence. Jim has worked on phylogeny, evolution, and biogeography of several living plant groups, especially the tropical family Annonaceae, the largest family of primitive angiosperms. His current main project aims to integrate Early Cretaceous fossils into the predominantly molecular phylogeny of living primitive angiosperms and to evaluate implications of the results for morphological evolution.

Eldridge MooresEldridge M. Moores
Distinguished Professor Emeritus
Ph.D., Princeton (1963)
2211A Earth & Physical Sci | 530-752-0352
Structural Geology and Tectonics

Professor Moores' Interests lie in tectonics, structural geology, and petrology;  ophiolites and their significance, the tectonics of Alpine-type mountain belts, Cordilleran tectonics, Precambrian tectonics, and K-12 education and public awareness of Earth Science. His field experience has included work and/or field excursions in about 60 countries including all seven continents. Moores is relatively fluent, if rusty, in Modern Greek, German, and French, and can survive in Italian and Spanish. He is the author or co-author of over 130 publications, including two textbooks (with R.J. Twiss), entitled Tectonics, and Structural Geology (2nd Ed),  monographs, and books for a popular audience. Eldridge is prominently featured in John McPhee's books Assembling California and Annals of the Former World. He was Editor of Geology from 1981-87, and Science Editor of GSA Today from 1991-95, 1996 President of the Geological Society of America and 2004-2008, Vice President of the International Union of Geological Sciences.

Jeff MountJeffrey F. Mount
Professor Emeritus
Ph.D., UC Santa Cruz (1980)
Paleoclimate and Paleoenvironmental Change

Fluvial geomorphology, ecogeomorphology, river and water resource analysis. Research emphasis on the geomorphology and ecology of rivers and streams, their response to changes in land use/land cover and flow regulation, and their restoration and assessment. Projects include restoration of river floodplains, management of levee systems in floodplain/estuary systems, re-operation of hydropower systems to improve aquatic ecosystems and adapt to climate change, and restoration of spring fed streams and meadow systems. Outreach includes assisting agencies and non-profits in assessment and formulation of river management policies.

Sarah RoeskeSarah M. Roeske
Research Geologist Emerita
Ph.D., UC Santa Cruz (1988)
1109 Earth & Physical Sci | 530-752-4933
Structural Geology and TectonicsIgneous and Metamorphic Petrology

Structural geology and metamorphic petrology. Combine detailed macrostructural analysis in the field with microstructural studies, metamorphic petrology, and geochronology, in order to solve tectonic problems. Current research topics include the tectonic evolution of convergent margins in Alaska and Argentina, with a focus on determining type, age and relative significance of different periods of fault movements. Related problems include uplift of high P/low T metamorphic rocks and role of strike-slip faults at convergent margins.

Jim RustadJames R. Rustad
Professor Emeritus
Ph.D., Minnesota (1992)

Interfacial and mineral surface geochemistry; mineralogy; mineral physics. Research is focused on computational chemical models of interfacial structure as well as surface charging, sorption, dissolution, and precipitation phenomena at oxide-water interfaces. Computational methods are also applied to problems in mineralogy and in aqueous and silicate melt geochemistry, including physics of hydrated minerals, ligand exchange and electron transfer reactions.

Peter SchiffmanPeter Schiffman
Professor Emeritus and Research Geologist Emeritus
Ph.D., Stanford (1978)
GeochemistryIgneous and Metamorphic PetrologyNEAT

Professor Schiffman's interests are in alteration petrology and mineralogy of active and fossil hydrothermal systems in terrestrial and submarine settings. In retirement, Peter is rediscovering his love for traditional music: he is a co-host of The Folk Brothers on Davis community radio KDRT (, and he also sings and plays guitar with Uncle Fergie’s House Band.

Don TurcotteDonald L. Turcotte
Distinguished Professor Emeritus
Ph.D., Caltech (1958)
2211A Earth & Physical Sci | 530-752-6808

Professor Turcotte has worked on a wide variety of problems in geodynamics. Many of these are included in his textbook (with Gerald Schubert) Geodynamics (3rd edition). He has also worked on a wide variety of applications of fractals and chaos to problems in geology and geophysics. Many of these are included in his textbook Fractals and Chaos in Geology and Geophysics (2nd edition). Don currently supervises graduate student research on induced seismicity and the distribution of carbon in the earth. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences.

Rob TwissRobert J. Twiss
Professor Emeritus
Ph.D., Princeton (1971)
Structural Geology and Tectonics

Professor Twiss' general research interests include the mechanisms and mechanics of rock deformation and the interpretation of associated structures. His research involves the inference of rotational components of deformation from inversion of seismic first-motion data and fault-slip data, using micropolar continuum theory; and the use of fault systematics to infer large-scale brittle deformation. Earlier research interests include paleopiezometry, which is the use of the microstructures of ductilely deformed mineral grains to infer the paleostresses associated with deformation; and the systematics of fold geometry. Twiss co-authored the textbooks Structural Geology, 2nd Edition (Twiss and Moores, W.H. Freeman & Co., 2007) and Tectonics (Moores and Twiss; Waveland Press, 2014).

Ken VerosubKenneth L. Verosub
Distinguished Professor
Ph.D., Stanford (1973)
3133 Earth & Physical Sci | 530-752-6911
Geophysics; Earth-Surface Processes

For much of his career, Ken Verosub has used the magnetic properties of rocks, sediments and soils to determine the behavior of the Earth's magnetic field, the ages of sedimentary sequences, the motions of tectonic plates, and the history of the Earth's climate during the past 40 million years. Recently he has become more generally interested in the influence of geologic processes on the development of societies, civilizations and cultures. In pursuit of this interest, he spent the 2009-2010 academic year as a senior science advisor for water and climate issues in the U.S. Department of State. In addition to on-going paleomagnetic and environmental magnetic studies, he is working on volcanic eruptions that have caused global cooling, seismic risk and subsidence problems in the Sacramento-San Joaquin Delta, the identification of deep groundwater aquifers and the determination of river flows directly from geospatial imagery.

Rob ZierenbergRobert A. Zierenberg
Professor Emeritus
Ph.D., Wisconsin (1983)
1105 Earth & Physical Sci | 530-752-1863
GeochemistryEarth-Surface ProcessesIgneous and Metamorphic Petrology

Aqueous geochemistry; stable isotope geochemistry; economic geology. Research has focused on water/rock interaction in active and ancient hydrothermal systems, including the "black smokers" on the mid-ocean ridges. Research topics include the geology and geochemistry of sulfide deposits and hydrothermal alteration in seafloor hydrothermal systems and on-land analogs. Hydrothermal activity at sediment-covered portions of the northern Juan de Fuca Ridge and southern Gorda Ridge seafloor spreading centers have been a long term research interest, including participation in Legs 139 and 169 of the Ocean Drilling Program. The Iceland Deep Drilling Project is providing new opportunities to investigate water/rock interaction in the deep, high-temperature roots of hydrothermal systems. Other interests include the environmental effects of mining, particularly the generation of acid mine drainage, mercury contamination in Clear Lake related to the abandoned Sulphur Bank Hg mine, the geochemical and biological cycling of sulfur, and sulfur isotope geochemistry.