Areas of Emphasis in Graduate Study and Research
Research opportunities in planetary geology span several disciplines, including remote sensing, experimental and theoretical geochemistry, experimental petrology, laboratory spectroscopy, and field-based research on planetary analog terrains. Particular emphasis is placed on understanding the magmatic evolution of Mars and the Moon, Martian sedimentological and aqueous alteration processes, and the mineralogical and physical properties of planetary regoliths. Facilities and equipment available for pursuing planetary geology studies include (1) a custom-built mid-IR emission spectrometer, (2) a UV-visible-near-IR reflectance spectrometer, (3) a micro-FTIR imaging spectrometer, (4) a micro-Raman imaging spectrometer, (5) a nano-FTIR spectrometer and imager, (6) a micro X-ray fluorescence spectrometer built to replicate the performance of the Mars 2020 PIXL instrument, (7) a pressure and temperature-controlled environmental chamber for infrared spectral studies under simulated lunar, Martian, and asteroid environments, (8) a low-temperature experimental geochemistry laboratory, (9) a fully-equipped experimental petrology laboratory capable of simulating conditions from deep within planetary interiors to the surface, (10) a portable thermal hyperspectral imager, Raman spectrometer and visible/near-infrared spectrometer for field studies, and (11) an image processing facility.
Remote sensing studies make use of a variety of instruments orbiting Mars and the Moon as part of several missions, including Mars Global Surveyor, Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, OSIRIS-REx, and the Lunar Reconnaissance Orbiter, as well as instruments carried on landed missions, notably the Mars Exploration Rovers Spirit and Opportunity, the Mars Science Laboratory rover Curiosity, and the Mars 2020 Perseverance rover. Current projects using data from these missions are focused on understanding the presence of salts, clays, and other minerals on the Martian surface, evaluating the composition and evolution of the Martian crust and sedimentary record, and determining the origin of unique lithologies on the lunar surface.
Examples of experimental projects currently underway involve understanding the conditions of formation of secondary minerals formed in surface water settings on the ancient surfaces of Mars and the Earth; the spectral properties of isochemically-altered synthetic Martian basalts and glasses, and X-ray amorphous sulfates; determining the mid-IR optical constants of a range of common silicate minerals; determining large-scale crustal evolution of Mars through magmatic evolution, metamorphic overprinting, alteration of wallrock by exsolving magmatic fluids, and precipitation of sublimates at the surface; evaluating the effect of degassing on lunar apatite in order to assess the true volatile budget of the Moon; determining the SiO2 speciation in lunar granites; and characterizing the mineralogy and organic content of carbonaceous chondrite meteorites and samples from the near-Earth asteroid Ryugu.
Seismology, Tectonics, and Geophysics
A primary focus in seismology and tectonics is the determination of detailed three dimensional earth structure, from the core to the surface, and related studies on the dynamics that drives mantle convection, deformation of the lithosphere, and plate tectonics in general. Particular emphasis is placed on interdisciplinary research and collaboration, where inferences made from seismological, geodynamic, and geodetic investigations are integrated with findings from the fields of mineral and rock physics, geochemistry, and petrology. Areas of specific focus in seismology include inner core structure, anisotropy, and attenuation, outer core structure, core-mantle boundary structure, upper mantle structure, strong ground motion studies, earthquake source parameter studies, and theoretical studies on seismic wave propagation. Investigations in tectonophysics include the coupling between mantle convection and lithospheric dynamics, the development of the kinematics, mechanics, and seismicity within plate boundary deformation zones, and the inference of mantle flow beneath the lithosphere. Current projects involve using earthquake and space geodetic data to infer the deformation fields and employing numerical, analytical, and analog modeling to understand surface geodynamical observations, ranging from geoid, topography, plate motions and surface deformations in the global and regional scales to the partitioning of strain and tectonic implications at geometrically complex plate margins. Research in shallow subsurface geophysics includes field geophysical surveys of glaciotectonic deformation of Long Island sediments using ground penetrating radar and electrical resistivity.
Mineral and Rock Physics
Research in these fields focuses on the investigation of the structure and composition of the Earth, geophysical properties of Earth materials, and the mechanical behavior of the crust and mantle. An important emphasis is the study of high-pressure and high-temperature phases and assemblages, particularly those of relevance to the mantle. In situ measurement of elastic properties, compressibility, and determination of crystal structure complement studies of high-pressure phase relations for constraining models for Earth's mantle and equations of state for mantle phases. Specific projects include determination of ultrasonic wave velocities of minerals and rheological determination of the strength of minerals at the pressure and temperature conditions of the Earth's mantle to depths greater than 500 km. Research initiatives in these areas are closely linked to the activities of the Mineral Physics Institute at Stony Brook and the NSF Consortium for Materials Properties Research in Earth Sciences [COMPRES]. Facilities available in the Department of Geosciences and the Mineral Physics Institute include equipment for ultrasonic interferometry, Brillouin spectroscopy, and multi-anvil apparatus for experiments at high pressure and temperature; these are all integrated with synchrotron X-ray sources at the NSLS. Complete single-crystal and powder X-ray diffraction facilities and transmission electron microscopy and electron diffraction are available.
Crystal Chemistry and Crystallography
The department has a strong background in the study of earth and planetary materials at the atomic and molecular level, and in using the results of these studies to interpret the properties of materials constituting planets, including Earth from crust to core. Two clusters of faculty, including the Mineral physics Institute (MPI) concentrate on the behavior of minerals in planetary crusts and Earth’s Interior, respectively. Both employ a wide range of structural probes, some located in the department and others located at national and international synchrotron X-ray and neutron facilities. Within the department, extensive facilities for powder X-ray diffraction, with capabilities for in situ high-temperature and high-pressure studies exist. Projects emphasize crystal structure studies on oxides, hydroxides, sulfides, carbonates, and silicates, including characterization of phase transitions, ordering phenomena, and ion exchange. Convenient access to the Brookhaven National Laboratory, which hosts the National Synchrotron Light Source II, NSLS-II, and Center Functional Nanomaterials, CFN, provides opportunities for unique experiments requiring specialized high-intensity X-ray sources. Other projects utilize X-ray absorption spectroscopy to examine local structure in minerals and neutron diffraction for studies of hydrous phases. Many of the department’s faculty are actively engaged in the design and construction of the next generation of beamlines required for high pressure and environmental investigations. These facilities are being designed with the requirements of the Stony Brook and wider national and international user base in mind.
There are broad opportunities for graduate study and research in many areas of geochemistry. Major departmental strengths include isotope and trace-element geochemistry, aqueous and hydrothermal geochemistry, and theoretical and experimental geochemistry across a range of conditions, from low-temperature aqueous systems to mineral-melt systems. All programs are founded in experimental and analytical work, and there are ample opportunities to integrate experimental work with field studies and computational approaches. Specific areas of research utilizing trace elements and radiogenic isotopes include evolution of Archean and Phanerozoic crust and geochronology of lithologic assemblages. These integrate with petrologic studies of sedimentary, metamorphic, and igneous terrains throughout the world. Research involving the chemistry and structure of sulfide and carbonate mineral surfaces are among the programs in low-temperature aqueous geochemistry; these include emphasis on geocatalysis, crystallization and trace element incorporation mechanisms, as well as the role of sulfides in the origin of life. Field-related studies focus on marine and continental paleoenvironments and climates . High temperature geochemical research focuses on experimental and theoretical investigations of melt and glass structure.
Experimental and analytical work makes use of the department's atomic emission spectroscopy, quadrupole, multicollector inductively coupled plasma mass spectrometers (ICP-MS), two thermal ionization mass spectrometers (TIMS), and dual-inlet and elemental analysis isotope ratio mass spectrometers (DI-IRMS and EA-IRMS), X-ray diffraction facilities, solid-state nuclear magnetic resonance (NMR) spectrometers, and two synthesis and experimental petrology labs. Additional work uses facilities in conjunction with the Center for Molecular Medicine at Stony Brook and in other Stony Brook departments as well as at nearby Brookhaven National Laboratory, including the NSLS.
Research in petrology focuses on experimental simulation of igneous processes in order to further our understanding of planetary evolution. These processes include those relevant to magma genesis and evolution in the source region of mid-ocean ridge basalt, development of magmatic diversity in subduction zones, crystallization of the lunar magma ocean, and degassing of reactive volcanic gas. Recent projects on volcanic processes on Mars have focused on simulating the formation of volcanic gas by magma boiling. This allows us to investigate the nature of minerals formed via gas condensation and through reaction between gas and volcanic glass. Recent projects on mid-ocean ridge and subduction zone magma source regions focus on the evolution of the residuum from partial melting and role it may have played in the formation of highly anorthitic plagioclase. Experimental petrology also extends into peripheral fields where mineral or materials synthesis is needed for structural, spectroscopic, isotopic, and toxicity studies. Recent experiments, for example, have produced OH-poor apatite for structural studies, new lunar simulants for toxicity studies, and various minerals for IR characterization.
Research initiatives in sedimentary geology at Stony Brook integrate geochemistry and geochronology with field, petrologic, and stratigraphic studies. Trace element and isotopic studies of marine and terrigenous sedimentary rocks provide information on their provenance, age, and composition, which yield insight to broader issues of crustal evolution, including sediment subduction, growth of continental crust and the sedimentary mass, and recycling of sedimentary rocks. Carbonate rocks and their diagenesis are another important area of research that utilizes a wide range of approaches. Petrography is combined with microanalytical techniques for trace elements and both stable and radiogenic isotopes to reconstruct the diagenetic environments and the physicochemical characteristics of paleohydrologic systems. Luminescence dating techniques are versatile methods that provide ages for a broad range of geological contexts. Emphasis is also placed on the quantitative modeling of water-rock interactions. A strong component of field work is common for studies of both clastics and carbonates. For many of of our field sites, an emphasis is placed on their suitability for understanding sedimentary processes on the ancient surface of Mars, including the generation of clastic sediments in modern basaltic terrains, and the conditions of carbonate mineral precipitation and preservation in shallow Proterozoic seawater recorded in iron formations. Analytical facilities include the department's optical and cathodoluminescence petrography facilities, a ICP-MS and TIMS mass spectrometry lab, a light stable isotope lab, a luminescence dating lab, X-ray diffraction facilities, and a variety of facilities at the NSLS.