The petrology, mineral chemistry and alteration history of the Martian meteorites, and what they tell us about the crust of Mars.
The recovery and classification of Antarctic meteorites and micrometeorites.
The recent history of the East Antarctic icesheet and its relationship to polar meteorite concentrations.
Studies of terrestrial analogs to igneous planetary materials, such as "primitive" archean ultramafic complexes.
Cryogenic weathering processes and ice / rock interactions.
The geochemical controls on biological activity in cryogenic settings.
The general petrology and mineral chemistry of mafic and ultramafic plutonic rocks.
Geological mapping and analysis via planetary images.
Statistical modeling of particle breakage, movement and recovery.
Research Skills:
Electron microprobe (EMP) analysis including both EDS (energy dispersive spectroscopy) and WDS (wavelength dispersive spectroscopy) systems
Scanning and transmission electron microscope(SEM, TEM) analysis
Secondary ion mass spectrometry (SIMS) for major, minor and trace element analysis
Petrographic microscope analysis of thin-sections and polished mounts
Fluid and melt inclusion analysis
Stable light isotope analysis
Microparticle handling and mounting for analysis
Image analysis for remote sensing and chemical mapping studies
Mathematical and statistical modeling of geological processes
Research Philosophy:
I approach my research from a broad, interdisciplinary, and fundamentally geological viewpoint. Although technology now lets us observe and measure nature at nanometer and femtogram scales, realistic interpretations of the history experienced by geological materials are easily lost when working with only the finest detail. The power of geology lies in the ability to synthesize chemical, physical, and observational data at a range of scales so that natural processes are put into a realistic context applicable to the larger world.
I love to discover new things and learn their place among known geological materials and processes. I also believe that advanced analytical tools are at their most useful when a full baseline of standard tools have already been applied, so I pursue the full hierarchy of analysis from basic to sophisticated. I often engage new or underused analytical techniques through collaborations, and do not hesitate to pass on my data and ideas to colleagues when I think it will improve our understanding of a problem.
I am also a firm believer in curiosity-driven (rather than funding-driven) research. When a problem interests me, I find ways to pursue it, or encourage others to do so, and don’t let programmatic considerations stand in my way. I am not afraid to use my research funding outside the bounds of original proposals, and while not every program manager loves my style, it has led to rapidly evolving research, successful proposals and continuous funding.
Active awards:
Greenland Search for Meteorites program (GREENSMET), funded by National Geographical Society, 2002-2003 ($25k).
Antarctic Search for Meteorites program (ANSMET), funded by NSF's Office of Polar Programs-Antarctic Geology and Geophysics program, 2000-2006 ($420k).
Recovery and Study of Antarctic meteorites. Funded by NASA Cosmochemistry program, 2001-2004 ($575k).
Logistical support for the recovery of Antarctic meteorites. Funded by NASA Cosmochemistry program, 2002-2005 ($1,481k).
Studies of Martian Meteorite ALH84001, NASA's Ohio Space Grant College, 2000-2003 ($54k) (support for Ph.D. candidate C. Corrigan).
Examination of RADARSAT images in support of ANSMET program, funded by Alaska SAR facility and NASA, 1999 - present (free images, no cash).
Recent previous awards:
Multi-year collections of micro-meteorites from the South Pole Water Well, Antarctica ($90k). NSF Office of Polar Programs-Glaciology 2000-2001 (Co-investigator).
Antarctic Search for Meteorites program (ANSMET), funded by NSF's Office of Polar Programs-Antarctic Geology and Geophysics program, 1997-2000 ($260k).
Electron Microscopy Survey of carbonate-bearing regions of ALH84001, funded by NASA Ancient Martian Meteorite program 1997-1999 (extended into 2000) ($120k).
Antarctic Search for Meteorites program (ANSMET), funded by NSF-OPP-Geology and Geophysics program, 1992-1998 ($472k). With W.A. Cassidy, University of Pittsburgh.
Retrieval and analysis of extraterrestrial particles from the water well at the South Pole Station, Antarctica, funded by NSF's Office of Polar Programs-Antarctic Glaciology program, 1994-1996 ($178k). With S. Taylor and J. Lever, CRREL.
Studies of South Pole Water Well micrometeorites, funded by NASA Johnson Space Center Faculty Support program; 1996-1998 ($15k).
Support for Meteorite Working Group meeting, funded by NSF-OPP-Geology and Geophysics program, 1992-1998 ($22k).
Flora Stone Mather Alumni Association Support for
student attendance at scientific meetings, 1996-97 ($2k).
Meteorite recovery efforts in Antarctica. The Antarctic Search for Meteorites (ANSMET) program has been active since 1976 and is currently funded through 2006. I have been the principal investigator of this program since 1991, leading 11 expeditions and participating in several others. In addition to recovering meteorites, our annual expeditions collect ice movement, ablation, and climatological data to explore the relative importance of the various processes (ice movement, ablation and climate change) that together produce meteorite concentrations. See the Antarctic Search for Meteorites website here.
Study of the famous Martian meteorite ALH84001. A continuing multi-dimensional examination of the alteration history of this igneous meteorite. Analytical instruments that work on a variety of scales are being used to characterize a few uniquely large occurrences of secondary minerals in the rock. The goal is a comprehensive understanding of the alteration history of the meteorite explaining how, when and why the various alteration minerals were formed. Some specific aspects of current interest include characterizing a previously undescribed second generation of carbonate within the rock, exploring the effects of impact-induced thermal decomposion of mixed carbonates, and the rheology of feldspathic glasses (with graduate student C. Corrigan and undergraduate M. Garrels).
Meteorite recovery efforts in Greenland. With Antarctic meteorite concentrations as a model, we have used radar, visible light images and climatological data to identify regions of the Greenland icesheet that exhibit analogous iceflow and meteorological conditions and thus have an enhanced likelihood of harboring meteorite concentrations. A key region has been located in central east Greenland and a four person expedition is planned for August, 2003 (with H. Haack, U. Copenhagen and A. Meibom, Stanford U.).
Study of the climatological conditions present during weathering of Antarctic rocks. A set of terrestrial rocks with internal and surface instrumentation is being deployed in a variety of Antarctic settings where they will record temperature and other climatic variables. The goal is to better constrain the conditions under which cryogenic weathering takes place. This data will be used in a larger petrographic study aimed at characterizing specific mineral reactions that occur during cryogenic weathering (with high school teacher A. Caldwell and undergraduate student D. Howe).
Study of the relationship between microclimate and biological activity in high-altitude, snow-free areas of Antarctica. Snow-free areas near meteorite concentration sites provide an excellent endmember for studies of biological activity under extreme cryogenic conditions- much colder and drier than the well-known Dry Valleys. In 2002 we will deploy a suite of intelligent, autonomous sensors (a Sensorweb) that will monitor microclimate at a variety of points in an Antarctic "micro-oasis". Later deployments will also include sampling of soils and other substrates from these sites to allow an investigation of the microclimatic controls on microbial activity. This study is likely to be expanded to include studies of nutrient controls and microbial monitoring using metabolic sensors. Our goal is to prove the ability to pinpoint and characterize instances of maximum biological activity in extremely limiting environments (with K. Delin of JPL and undergraduate student M. Adams).
Survey of "sterile" Antarctic lakes. While significant research has sought to characterize those Antarctic lakes where life is extant in spite of extreme environmental conditions, little attention has been turned to other Antarctic lakes where conditions are only slightly more extreme and yet biological communities are extremely limited or absent. Through the study of a series of sediment and water samples collected from small, high-altitude Antarctic lakes we hope to understand the geochemical and climatological controls that determine the limits on biological activity. Perhaps a larger goal is to determine whether ANY site on our planet where liquid water has been present can be considered truly "sterile". (With J. Lisle of USGS).
Studies of cryoconite formation Climatic conditions determine why some rocks sink in the ice and others don't. We are developing a thermodynamical model that predicts when a rock will sink given air temperature, ice temperature and solar illumination to provide an improved understanding of the dynamics of rocks in and on ice in a variety of settings, from fast glaciers to hard cold planetary surfaces (with D. Moog, CWRU).
Studies of the Sirius Formation. The Sirius formation is a glacial till about 2.3 million years old. It is found on the highest peaks of the Transantarctic Mountains yet contains abundant marine diatoms, and its origin is enigmatic. Some speculation has begun that the oceanic debris might have been introduced by a giant impact, and we are currently cataloging the mineral content of the till to establish the presence or absence of impact related materials (With undergraduate student H. Boyd).
Other studies (less active or planned)
Studies of Antarctic micrometeorite particles. I have an extensive collection of micrometeorite-bearing sediments recovered from the South Pole Water Well, aeolian sediments, and other Antarctic sources. Thes have enormous potential for improving our understanding of the breadth of material present in our solar system and have only begun to be characterized. Of particular current interest is sediment from the BIT-58 layer found in Antarctic ice in 1996. This layer consists of ablation debris from a meteor that passed by 2 million years ago, and serves as critical ground truth for dispersed extraterrestrial signals (such as Ir concentrations associated with impact events).
Studies of Munro Township Basalts. A well-preserved set of outcrops of 2.3 billion year old basalts in Munro Township, Ontario, record an interesting period in the development of basalts on our planet. I have conducted several reconnaissance trips to the region and found a second set of outcrops, less accessable than those commonly studied, that offer broader and perhaps more complete exposure of the famous Theo’s and Fred’s flows.
Remote sensing studies of Mars using Mars Global Surveyor data. There now is a huge archive of unexamined images, topographical and thermal emission spectroscopy data from the Mars Global Surveyor spacecraft (more than 80,000 images and data files). I have begun planning a combined petrology / remote sensing study whose goal will be to identify specific volcanic and igneous outcrops on Mars that are consistent with the known martian meteorites. The study will use MOCS and THEMIS data to locate favorable dust-free outcrops, MOLA data to establish the physical dimensions of exposed flows, and TES data to identify mineralogically important elemental ratios.
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