Our research group uses remote sensing techniques and laboratory spectroscopy to investigate planetary surface processes. Presently our research activities can be divided into three broad themes: 1) spacecraft data analysis, presently with a focus on Mars, 2) laboratory spectroscopy and remote/field studies of planetary analog surfaces on Earth, and 3) environmental remote sensing.
Characterizing Planetary Surfaces Using Spacecraft Data Analysis
The principal objective of this research theme is to understand the volcanic, aqueous and sedimentary histories of planetary surfaces that we cannot study in-situ. Presently, my group focuses on Mars because of the abundance of data and the rich set of geologic processes that have occurred there. Through site-specific, integrated compositional and geologic mapping, we have made several contributions towards understanding Martian crustal evolution and alteration. Example investigations include:
Analysis of subsurface rock unit compositions and distributions exposed by impact craters (in progress, by graduate student Cong Pan)
Compositional/geomorphological characterization of materials in a putative paleolake basin (in progress, by graduate student Adam Nazarian)
Detection of ancient flood basalts that likely formed during tectonic development of giant impact basins (Rogers and Nazarian, 2013)
Analysis of systematic compositional differences between fine-grained regolith and bedrock surfaces and the implications for alteration processes during regolith development (Rogers et al., 2009; Rogers and Fergason, 2011; Bandfield et al., 2010)
Global-scale mapping of major surface mineralogic assemblages with thermal infrared data, showing variations associated with crustal terranes, age and latitude (indicating frost/ice-related alteration processes) (Rogers et al., 2007; Rogers and Christensen, 2007)
Detection and characterization of mineralogically unique volcanic units exposed in channel walls, indicating extensive olivine-rich volcanic flows (Rogers et al., 2005)
Mineralogical characterization of candidate landing sites for the Mars Science Laboratory (Rogers and Bandfield, 2009)
Example from previous work (left): High resolution data from the Mars Odyssey Thermal Emission Imaging System (THEMIS) show compositional stratification in the upper crust of Mars. Layers of bedrock containing ~25% olivine (red) are exposed in the walls of the Ares Vallis outflow channel, as well as in nearby impact crater ejecta (Rogers et al., 2005).
Laboratory Spectroscopy and Mars Analog Studies
To enhance interpretation of remotely acquired spectra from planetary surfaces, we are characterizing the spectral properties of rocks and minerals of interest in the laboratory and conducting combined satellite-based/field-based studies of planetary volcanic analog terrains. Most of the projects described below focus on understanding how alteration or structural transitions affect the measured spectral characteristics of relevant planetary analog samples:
Investigation of crystallinity controls on the spectral properties of sulfate phases. Experimental studies on the stability of sulfate minerals under Martian conditions have shown that some sulfate phases on the surface are likely to be poorly crystalline or amorphous. We are generating these phases in the laboratory and characterizing the local structure and spectral properties for comparison to planetary data. (in progress, by Eli Sklute and Heidi Jensen, collaborating with Rich Reeder and Brian Phillips)
Characterizing the spectral properties of synthetic Martian basalts that have been altered under various conditions (in progress, by Marcella Yant, collaborating with Nekvasil and McLennan). This will allow direct spectral comparison of altered Martian basalts with the Mars mission data, and will close a knowledge gap that exists between a) detailed mineralogical information obtained from controlled geochemical experiments on basalt weathering and b) spectral studies of naturally weathered basalts and tephras.
Characterization of the mid-infrared spectral mixing behavior of sedimentary rocks and their constituents. Because rocks of sedimentary origin comprise a significant fraction of the Martian surface, it is important to understand the spectral properties of these potentially complex mixtures and whether quantitative mineralogic composition of sedimentary rocks may be determined from mid-infrared spectra (in progress, by Mike Thorpe and Cong Pan)
Assessment of our ability to interpret planetary volcanic terrains remotely through combined remote/field/lab studies of Hawaiian volcanic flows (collaboration with Jacob Bleacher at Goddard Space Flight Center)
Environmental Remote Sensing
We are using aerial thermal imaging to locate potential regions of submarine groundwater discharge (SGD) into Long Island's near-shore environments. SGD brings nitrates and other nutrients into harbor waters, which feeds harmful algal blooms and disrupts natural ecosystems. In the image to the left, warm plumes represent groundwater discharging into cooler harbor waters. Aided by this imagery, Stony Brook collaborators and graduate students can better target locations to sample the chemistry and flux of groundwater discharge.
My group is also beginning a study using satellite and aerial imagery to characterize temporal changes in infrared properties of playas and other desert surfaces, with the goal of understanding how these changes may relate to susceptibility of dust emissions from these surfaces. Airborne dust is a significant radiative force on Earth's climate, as well as a health hazard, thus it is important to characterize the major source regions of dust.
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