James W. Head III.
Jim Head's research focuses on the nature of geological processes and the ways in which they combine in the geological record of the planets. Present research emphasizes the nature of volcanic and tectonic processes. Recent activities include theoretical and observational analyses of volcanism on the Moon, Mars and Venus with field studies of active eruptions in Hawaii forming an important element. Studies of tectonic activity emphasize the nature of lithospheric deformation on the planets and the different ways in which internal planetary evolution is manifested in deformational patterns. Comparative planetological studies form an important area of interest, and a focal point for these studies is the mechanism or mechanisms of lithospheric heat transfer on terrestrial planetary bodies. Venus, because of its similarities to the Earth, is a subject of intense research at the present time, including collaboration with scientists from Russia Analysis of Soviet and Russian space mission data is possible through institution-to-institution agreements between the two major space science institutes (Institute of Space Research and the Vernadsky Institute) and Brown University. These involve twice-yearly meetings in the U.S. and Russia in which students and faculty participate. There is additional interest in the nature and evolution of outer planet satellites, with particular emphasis on Io, Europa, Ganymede and Callisto, the satellites of Jupiter. Professor Head is involved in planning for the upcoming Galileo mission to Jupiter, the Russian Mars 1996/1998 missions and the U.S. Mars Surveyor program. Analysis of terrestrial data, including data from the sea floor and Shuttle Imaging Radar missions, is an important part of the program. Students working with Professor Head have an opportunity to participate in the planning, mission operations, and data analysis for these missions.
Head, J.W., S. Murchie, J.F. Mustard, C.M. Pieters, G. Neukum, A. McEwen, R. Greeley, E. Nagel and M.J.S. Belton (1992) Lunar impact basins: New data for the western limb and farside (Orientale and South Pole-Aitken Basins) from the first Galileo flyby, Journal of Geophysical Research, 98, 17149-17181.
Wilson, L. and Head, J.W. (1994) Mars: Review and analysis of volcanic eruption theory and relationships to observed landforms, Reviews of Geophysics (in press).
Head, J.W., E.M. Parmentier and P.C. Hess (1994) Venus: Vertical accretion of crust and depleted mantle and implications for geological history and processes, Planetary and Space Science, in press.
Head, J.W. and Wilson, L. (1992) Lunar mare volcanism: Stratigraphy, eruption conditions, and the evolution of secondary crusts, Geochimica et Cosmochimica Acta, 55, 2155-2175.
Magee, K. and Head, J.W. (1993) Large-scale volcanism associated with coronae on Venus: Implications for formation and evolution, Geophysical Research Letters, 20, 1111-1114.
Burt, J.D. and Head, J.W. (1992) Thermal buoyancy on Venus: Underthrusting vs. subduction, Geophysical Research Letters, 19, 1707-1710.
Grosfils, E.B. and Head, J.W. (1994) The global distribution of giant radiating dike swarms on Venus: Implications for the global stress state, Geophysical Research Letters, 21, 701-704.
Keddie, S.T. and Head, J.W. (1994) Height and altitude distribution of large volcanoes on Venus, Planetary and Space Science, in press.
Head, J.W., Crumpler, L., Aubele, J., Guest, J. and Saunders, R.S. (1992) Venus volcanism: Classification of volcanic features and structures, associations, and global distribution from Magellan data, Journal of Geophysical Research, 97, 13153-13197.
Basilevsky, A.T. and Head, J.W. (1994) Global stratigraphy of Venus: Analysis of a random sample of 36 test areas, Icarus (submitted).
Head, J.W. and Wilson, L. (1994) Lunar graben formation due to near-surface deformation accompanying dike emplacement, Planetary and Space Science, 41, 719-727.
Paul C. Hess.
Professor Hess is a theoretically oriented petrologist whose research deals with the petrogenesis, solution chemistry and phase equilibria of planetary magmas. Recent work deals with the origin of basalts on the moon and on the ocean floor on Earth and the interplay of tectonics and magmatism on Venus.
Parmentier, E.M. and Hess, P.C. (1992) Chemical differentiation of a convecting planetary interior: Consequences for a one plate planet such as Venus. GRL, 19, 2015-2018.
Hess, P.C. (1994) The thermodynamics of thin liquid films. JGR, 99, 7219-7229.
John F. Mustard.
Dr. Mustard joined the planetary group as the W. M. Keck Foundation Assistant Professor for research in 1991. His research is focused on characterizing surface composition from remote sensing data and using this information to further our understanding of crustal composition and surface processes. One area of active research is directed towards Mars. Recent activities have centered on exploiting a unique data set acquired by a French instrument flown on the then Soviet space probe Phobos. From these efforts, detailed compositions of volcanic units from several Martian plain as well as from Valles Marineris have been derived that document substantial heterogeneities. Similarly, bright regions show a diversity in the amount and forms of water and alteration minerals. These results are now being used to further understand the volcanic evolution and alteration history of Mars. Another area of planetary research concerns the formation of lunar light plains and the early volcanic history of the Moon through analyses of data acquired by the Galileo space probe. Dr. Mustard is also active in studies of the terrestrial environment. A major effort is focused on developing stable and quantitative models for the detection and quantification of change in terrestrial systems. In addition, he has participated in numerous projects to study crustal composition of mafic and ultramafic terrains on the earth using data acquired from sophisticated advanced sensors. A central theme that lies at the heart of these efforts is the development, testing, and application of analytical models for extracting quantitative information from remote sensing data. This information is then integrated with related data sets using the advanced image processing facilities in the Planetary group for the various applications. The approach to the modeling of remote sensing data incorporates the theory and principles of spectroscopy, laboratory experiments using the extensive RELAB laboratory facilities, observations and applications, and field investigations to continually refine and advance our capabilities.
Mustard, J. F., Associations of soils and bedrock in the Kaweah serpentinite melange, CA, Remote Sensing of Environment,44, 293-308, 1993.
Mustard, J. F., S. Erard, J.-P. Bibring, J. W. Head, Y. Langevin, C. M. Pieters, Surface composition of Syrtis Major-Isidis Basin from imaging spectrometer observations: Implications for volcanism and surface processes, J. Geophys. Res., 98, 3387-3400, 1993.
Murchie, S. L., J. F. Mustard, and S. Erard, Spatial variations in the spectral properties of bright regions in Mars, Icarus 105, 454-468, 1993.
Mustard, J. F., Lithologic mapping of gabbro and peridotite sills in the Cape Smith fold and thrust belt with Thematic Mapper and airborne radar data, Canadian Journal of Remote Sensing, (in press), 1994.
Mustard, J. F., and J. F. Bell III, New composite spectra of Mars from 0.4 to 3.14 m, Geophys. Res. Letters, 21, 353-356, 1994.
E. Marc Parmentier.
Professor E.M. (Marc) Parmentier's research interests focus in planetary geophysics and tectonics. His work has recently centered on studies of the role of compositional buoyancy in the large-scale dynamics of planetary interiors. Partial melting to generate the crust of a planet creates chemically buoyant residual mantle. On Venus (Parmentier and Hess, 1992), in the absence of mantle flow associated with plate tectonics, this buoyant, refractory layer can collect at the top of the mantle. As this depleted layer thickens the melting temperature at the top of the underlying convecting mantle also increases and the degree of partial melting of mantle added to the depleted layer decreases. As the chemically buoyant depleted layer cools it becomes heavier than the underlying mantle. The accumulation and instability of the depleted layer occurs repeatedly over a substantial portion of the planet's evolution with a period of 300-500 Myr consistent with results of the Magellan mission is that the population of impacts craters give a surface age of about 500 Myr. Other work on Venus includes the origin of tectonic features (Zuber and Parmentier, 1990) and highlands on Venus (Bindschadler and Parmentier, 1990) as well as the distinctive corona features (Stofan, et al., 1991). His work (Hess and Parmentier, 1994) also examines the internal evolution of the Moon and how this relates to its surface magmatic evolution, specifically, the well described but not so well understood origin of the mare basalts. A model in which the dense ilemenite-rich cumulates that forms the last residual of the magma ocean sinks to the center of the Moon to form a core. This magma ocean residual is highly enriched in incompatible heat producing elements such as U, Th, and K. Radioactive heating of the core causes thermal instability of the overlying mantle which, as it rises, melts to generate mare basalt magma. This model explains two of the most important characteristics of mare basalt volcanism: its timing and the chemical requirement of deep melting of a source material that was a cumulate of the magma ocean.
P.C. Hess and E.M. Parmentier, Overturn of magma ocean ilmenite cumulate layer: implications for lunar thermal and magmatic evolution, Lunar Planet. Sci. Conf. 25, 541-542, 1994.
E.M. Parmentier and P.C. Hess, Chemical differentiation of a convecting planetary interior: consequences for a one plate planet such as Venus, Geophys. Res. Lett. 19, 2015-2018 (1992).
E.R. Stofan, D.L. Bindschadler, J.W. Head, and E.M. Parmentier, Corona structures on Venus: models of origin, J. Geophys. Res. 96, 20933-946 (1991).
M.T. Zuber and E.M. Parmentier, On the relationship between isostatic elevation and the wavelengths of tectonic surface features on Venus, Icarus 85, 290-308 (1990).
Carle M. Pieters
Professor Pieters has been a faculty member at Brown since 1980, after having worked several years at the Johnson Space Center in Houston and as a Peace Corps volunteer in Sarawak. Her general research efforts include planetary exploration and evolution of planetary surfaces with an emphasis on remote compositional analyses. Remote sensing techniques continue to be a primary exploration tool for understanding the surfaces of planets, and the application of remotely sensed data to problems in the geological sciences often requires incorporating additional information from other science areas (engineering, astronomy, physics, chemistry, mathematics, computer science, etc.). Compositional information is derived from visible, near-infrared, and mid-infrared radiation that has interacted with surface materials. Remotely acquired compositional information is primary data used to address a variety of geologic issues (recent examples include identifying and characterizing mafic plutons on the Moon, searching for possible parent bodies of the ordinary chondrites, and evaluating the effects of space weathering on planetary materials). The research approach at Brown concerning remote sensing information applied to geological problems for the Earth and planets combines direct measurement of surface properties, acquisition of supporting interpretive information from laboratory spectroscopic data, and development of theoretical models and analysis approaches that accurately model or predict the natural system.
Dr. Pieters is the Science Manager of the NASA/Keck Reflectance Experiment Laboratory (RELAB), a NASA-supported spectroscopy facility at Brown that operates from 0.3 to 25 mm. She is also the PI for the Planetary Data System (PDS) Spectroscopy Subnode of the Geosciences Node which is designed to provide access to spectroscopic information for the broad science community. Dr. Pieters is a member of the Science Team for the "Clementine" mission to the Moon in 1994 and will continue to maintain an active lunar and asteroid research program.
Fischer, E. M. and Pieters, C. M. (1993) The continuum slope of Mars: Bidirectional reflectance investigations and application to Olympus Mons, Icarus, 102, 185-202.
Pieters C. M. (1986) Composition of the Lunar Highland Crust from Near-Infrared Spectroscopy, Revs. Geophysics 24, 557-558.
Pieters C.M., Head J.W., Patterson W., Pratt S., Garvin J., Barsukov V.L., Basilevsky A.T., Khodakovsky I.L., Selivanov A.S., Panfilov A.S., Getkin Y.M. and Narayeva Y.M. (1986) The Color of the Surface of Venus, Science, 234, 1379-1383.
Pieters C.M. and Englert, P.A.J. (eds) (1993) Remote Geochemical Analysis: Elemental and Mineralogical Composition, New York: Cambridge University Press, 594 pp.
Pieters, C.M., Fischer, E.M., Rode, O. and Basu, A. (1993) Optical effects of space weathering: The role of the finest fraction, J. Geophys. Res., 98, 20817-20824.
Pieters, C.M. and McFadden, L.A. (1994) Meteorite and asteroid reflectance spectroscopy: Clues to early solar system processes, Ann. Rev. of Earth and Planet. Sci., 22, 457-497.
Sunshine, J.M. and Pieters, C.M. (1993) Estimating model abundances from the spectra of natural and laboratory pyroxene mixtures using the modified Gaussian model, J. Geophys. Res., 98 (E5) 9075-9087.
Malcolm J. Rutherford.
Professor Rutherford is an experimental petrologist whose research interests include petrogenesis of igneous rocks on the earth and other terrestrial-like planetary bodies, volcanological processes, and the nature and role of volatiles in igneous processes. He has support from both NSF and NASA for working on such problems as well as support for investigations pertaining to the rates of volcanic processes. Professor Rutherford and his students have developed a widely recognized expertise in experimenting with silicate magma systems in equilibrium with either sulfide or sulfate phases and vapor at high temperature and pressure. The importance of this work ranges from climate modification such as that produced by the 1991 eruption of Mount Pinatubo to the process of core formation.
Johnson, M.C. and Rutherford, M.J. (1989b) Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley Caldera, CA, volcanic
Metrich, N. and Rutherford, M.J. (1992) Experimental study of chlorine behavior in hydrous silicate melts. Geochim. Cosmochim. Acta, 56, 607-616.
Geschwind, C.H. and Rutherford, M.J. (1992) Cummingtonite and the Mount St. Helens magma system, Geology, v 20, p 1011-1014.
Rutherford, M.J., 1993, Application of experimental petrology to understanding volcanic processes, E.O.S. invited article, v 74, p 49 & 55.
Rutherford, M.J., and Devine, J.D., (in press) Pre-eruption P-T conditions and Volatiles in the 1991 Pinatubo magma, U.S. Geol Survey Prof Paper.
Finnila, A.B., Hess, P.C., and Rutherford, M.J., (in press) Assimilation by lunar mare basalts: melting of crustal material and dissolution of anorthite, JGR, planets.
Fogel, R.A. and Rutherford, M.J., (accepted by Geochemica) Magmatic volatiles in primitive lunar glasses: FTIR and EMPA analyses of Apollo 15 green and yellow glasses and revision of the volatile assisted fire-fountaining theory.
Holmberg, B., and Rutherford, M.J., 1994, An experimental study of KREEP basalt evolution, LPSC, XXV, 557-559.
Peter H. Schultz.
Impact cratering is one of the few processes affecting all planetary bodies. Consequently, the expression and occurrence of this record can provide clues for contrasting geologic evolutions. The planetary record, laboratory experiments, field studies, and theoretical approaches allow exploring a process at scales we hope we never witness. Two areas of personal interest have been the effect of impact angle on cratering and the role of the atmosphere in modifying the process. They are graphically revealed on Venus where these two variables contribute to distinctive asymmetries in the ejecta deposits and long, turbulent flows. We can further assess these effects by studying the terrestrial record, such as large low-angle impact in Argentina, which occurred within the last 2000 years. Different planetary environments (gravity and atmospheric pressure), laboratory simulations, and theoretical models allow testing our understanding under extreme conditions and to extreme scales. This approach has led to diverse studies including the atmospheric response to large-body impacts on the Earth, Venus, and Mars; erosion rates on Mars and Earth; martian lithology deduced from ejecta deposits; formation and evolution of impact basins; and impact-generation of orbiting debris.
As Director of both the Northeast Planetary Data Center and the RI Space Grant Program, Dr. Schultz shares his excitement for research through educational outreach activities throughout New England. He also serves as the Science Coordinator of the NASA-Ames Vertical Gun Range. He sees the topic of impact cratering increasing in importance as we better understand its terrestrial signature, its effects on past climates, and even its role in localizing resources.
Schultz, P.H. (1992) Atmospheric effects on ejecta emplacement and crater formation on Venus from Magellan. J. Geophys. Res., 97, No. E10, 16,183-16,248.
Schultz, P. H. (1992) Atmospheric effects on ejecta emplacement, J. Geophys. Res., 97, 11,623-11,662.
Crawford, D.A. and Schultz, P.H. (1993) The Production and Evolution of Impact-generated Magnetic Fields, International J. Impact Eng., 14, 205-216.
Grant, J.A. and Schultz, P.H. (1993) Erosion of Ejecta at Meteor Crater, Arizona. J. Geophys. Res., 98, 15,033-15,047.
Wichman, T.W. and Schultz, P.H. (1993) Floor-Fractured Crater Models of the Sudbury Structure, Canada: Implications for Initial Crater Size and Crater Modification, Meteoritics 28, 222-231.
Dr. Crumpler's research activities in the past have included petrology, field mapping and structural geology, as well as geophysical, meteorological, and numerical studies of Earth and other planetary bodies. Currently, my research is focused on physical and tectonic processes associated with volcanism and effusive volcanism. The massive catalog of all volcanic features on Venus nears completion and will hopefully be published as a Geological Society of America Special Paper. A recent article was published in Science regarding some additional aspects of this work on Venus in which we examined the distribution of volcanism and global geologic characteristics to see if there were any first order correlation's that related to internal dynamics of Venus at large scale, at least as recorded in the geologic record. A paper describing the neotectonic characteristics of the Springerville volcanic field in eastern Arizona was just completed and will be published this fall; in this work we attempt show young tectonic movements involving subtle, left lateral strike-slip deformation, pull-apart basins, and related structures displacing young basalt flows - on the Colorado Plateau! - that may relate to the continued clockwise rotation of the Plateau over the past 2 Ma. One recent research project is focused on understanding the complex strain histories associated with caldera formation based on detailed analysis of the strain history in well-preserved martian calderas. A major goal is to show that certain magma replenishment rates are characteristic of many volcanic feature on the terrestrial planets. These may be more diagnostic than chemical composition of the magmas in governing observed morphologies of volcanic centers. Other research in the paper stage is a comparison of the distribution of hot spots and major magmatic centers on Earth, Venus, and Mars. Another project involving Mars that is completed and in review is a 1:500,00-scale map of the Mutch Memorial Station (Viking Lander 1) region of Mar. I used data from this map at a recent workshop to support a proposal for using the Chryse Planitia region of Mars as a viable landing site for Mars Pathfinder Lander (NASA Discovery program) mission scheduled for 1996. The final landing site has subsequently been selected and is just east of the area I proposed. I just begun a new mapping project of Mars at 1:500,000-scale that extends from the central Chryse Planitia region onto the adjacent highlands will attempt to study the highland-lowland geologic transition with a "transect" or geotraverse approach. A research project with the Artificial Intelligence Lab at JPL has involved the use of complex decision tree algorithms in automatic identification of small land forms on Venus, and follows their successful Sky Cat which cataloged and classified more stellar objects than ever before. We have immediate plans to extend this research to global change and Earth observation research questions using satellite remote sensing data, specifically to the task of monitoring volcanic eruption activity. My plans for future research include the use of satellite remote sensing technology and artificial intelligence decision algorithms in monitoring volcanoes on Earth; the quantifiable mechanics of volcanic eruptions; the significance of volcanism in the modern environment; and relation of solid Earth characteristics to meteorology. I am responsible for maintaining the active volcanism bulletin board in Lincoln Field. Everyone should drop by periodically to see what is happening. Also I continue as the second vice chairman of the Planetary Geology Division of the Geological Society of America, and act as a tie to GSA for the planetary group. Educational emphasis is on popular geology ("planets, volcanoes, and dinosaurs"), tectonism and volcanism, physical volcanology, meteorology, field geological approaches to general geology, environmental geology, and planetary geology. I also continue to explore ways to use emerging power of personal work stations and computers for analysis and presentation of geological data and education. The Springerville volcanic field geologic map is appearing on a GSA CD as an interactive Supermap and is widely held across the country as being at the leading edge of the next generation of geologic mapping. I have a demonstration copy for anyone who may be interested.
Condit, C. D., L. S. Crumpler, and J. C. Aubele, 1:50,000 scale Lithologic, geochemical, and paleomagnetic maps of the Springerville volcanic field, Arizona: U. S. Geological Survey Miscellaneous Investigations map, Scale 1;100,0000, I- 2431, 1994.
L. S. Crumpler, J. C. Aubele, and R. Craddock, 1: 500,000-scale Geologic map of Central Chryse Planitia/Viking 1 Lander region, Mars. U. S. Geological Survey, MGM, in review, 1994.
L. S. Crumpler, J. C. Aubele, and J.. W. Head, Volcanic and magmatic features on Venus: A global survey. Geol. Soc. America Sp. Paper, in preparation,1994.
L. S. Crumpler, Head, J. W., and J. C. Aubele, Relation of major volcanic center concentration on Venus to global tectonic patterns. Science, 261, 591-595, 1993.
Head, J. W., L. S. Crumpler, J. C. Aubele, J. Guest, and R. S. Saunders, Venus volcanism: classification of volcanic features and structures, associations, and global distribution from Magellan. Jour.Geophys. Res., 97, 13153-13197, 1992.
C. B. Connor, C. D. Condit, L. S. Crumpler, and J. C. Aubele, Evidence of regional structural controls on vent distribution: Springerville volcanic field, Arizona: Jour. Geophys. Res., 97, 12349-12359, 1992.
Robert Pappalardo researches the geological histories of icy outer planet satellites and the processes that have shaped their surfaces through application of geomorphological, structural, and geophysical models to these satellites. Past research focused on Miranda, an icy satellite of Uranus. Examination of ridge and trough sets on Miranda led to the conclusion that large upwellings within the satellite shaped its surface. Present research concentrates on the ongoing encounters of the Galileo spacecraft with the Galilean satellites of Jupiter: Io, Europa, Ganymede, and Callisto. Previous research on Europa includes description of a region of tearing and separation of the satellite's icy lithosphere, investigation of a sea ice analog for the satellite's surface features, and identifciation of a probable volcanic flow that may be water-rich. New images of Ganymede and Europa are presently being returned by Galileo, revolutionizing our understanding of their geologies. Work continues on analysis of these new images and on planning the continuing Galileo observations of the jovian satellites.
Pappalardo, R.T., J.W. Head, G.C. Collins, and the Galileo Imaging Team, 1996. Stress and strain in Ganymede's grooved terrain: Structural analysis as revealed by Galileo imaging. GSA Abstr. Prog. (in press).
Pappalardo, R.T. and R.J. Sullivan, 1996. Evidence for separation across a gray band on Europa Icarus (in press).
Pappalardo, R.T., S.J. Reynolds, and R. Greeley, 1996. Extensional tilt blocks on Miranda: Evidence for an upwelling origin of Arden Corona. J. Geophys. Res. (submitted).
Pappalardo, R.T. and R. Greeley, 1995. A review of the origins of subparallel ridges and troughs: Generalized morphological predictions from terrestrial models. J. Geophys. Res. 100:18,985-19,007.
These various research activities and collaborative programs serve to illustrate that the research at Brown affords graduate students and visitors access to a variety of perspectives and approaches with other leaders in the field.