Basic Research

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Areas of Research

• Geomicrobiology and Biosedimentology
  • Biomineralization processes
  • Microbial Mats and Microbialites
  • Paleoecology and Paleoenvironments
  • Fossilization Processes (Taphonomy)
  • Invertebrate Ichnology (Trace Fossils)
• Astrobiology
  • Exploration Strategies for Mars & Europa
  • Life in Extreme Environments
• Early Metazoan Evolution
  • Origins of Multicellularity
  • Origin of Animals
  • Evolution of Colonial Organisms

 

Currently Funded Projects

1) With PhD candidate, Michael Thomas, I have been studying the role of cyanobacterial biofilms in the precipitation and microfabric evolution of carbonate (tufa) deposits in Mono Lake, eastern California. Mike plans to graduate in the Fall of 2010. The project has been funded by a NASA Exobiology/Evolutionary Biology Program grant.

2) Working with Masters candidate, Valeria Routt, I have been studying the morphogenesis and micropaleontology of oncoid stromatolites that form in karst stream systems of the Rio Mesquites, Cuatro Cienegas Basin, North Central Mexico. Valeria plans to graduate at the end of the Fall semester, 2009. The Cuatro Cienegas project received funding from the NASA Astrobiology Institute.

3) In collaboration with Linda Jahnke and Niki Parenteau (NASA Ames Research Center) I have renewed my earlier interests in siliceous hydrothermal spring environments in Yellowstone Park to understand their potential for preserving a fossil record of chemical biomarkers (lipids and their derivatives) over a broad range of pH and temperature. Our goal is to better understand the potential for lipid biomarker preservation and to understand the impact of post-burial diagenetic processes on the mineralogy and microtexture and biosignature retention in siliceous hot spring deposits. We hope to apply what we learn to better interpret the origin and biosignature potential of high silica deposits recently discovered on Mars. This project is funded by a grant from the NASA Exobiology/Evolutionary Biology program.

4) In collaboration with PhD candidate, Jorge Nunez and Prof. Kathleen Campbell (University Auckland, NZ) we have been looking at the diagenetic evolution of siliceous hydrothermal deposits by comparing modern siliceous hot spring deposits of the Taupo Volcanic Field with Miocene-aged silica sinters from the Coromandel Peninsula, New Zealand. Our goal is to better understand the preservation potential of siliceous sinters as they pass through diagenesis, tracking mineralogical, microtextural and paleontological features of siliceous sinters as primary opaline silica (which is metastable) transforms to cristobalite and finally quartz, during diagenesis. In collaboration with ASU Masters candidate, Vicki Mills, we are also looking at primary and secondary (authigenic) clay minerals of siliceous sinters, to understand if there is a relationship between minor and accessory mineral assemblages, pH and temperature. This work is supported, in part, by a NASA pre-doctoral fellowship (NESSF) to Jorge Nunez, as well as Lewis and Clark and National Geographic grants for New Zealand field work.

5) With Dr. Steve Ruff (ASU) and colleagues at NASA Ames and the University of Auckland, I have been conducting collaborative research to understand the spectral, mineralogical, microtextural and geochemical features of siliceous hot-spring sinters and other high silica deposits. This work is designed to create a context for interpreting the origin of high silica rocks and soils discovered at Home Plate in the Columbia Hills, Gusev Crater, Mars by the MER rover, Spirit. This work is funded by the Mars Fundamental Research Program and supports Masters student Vicki Mills, who is examining the clay mineralogy of siliceous sinters over a broad range of pH and temperature (see 5, above), the silica phase transitions that occur during diagenesis and impacts of diagenesis on biosignature preservation.

6) With now graduated Masters candidate, Jill Lockard, I have been characterizing the organic biosignature record of sulfate evaporates, over a range of depositional environments and ages. We have analyzed samples from about 25 different localities worldwide with the goal to better understand the potential of sulfate evaporites to capture and preserve a fossil biosignature record. We hope to use this work to provide a context for evaluating the astrobiological potential of sulfate evaporates that have now been discovered at many places on Mars. This work, which is continuing, was supported by an Arizona Space Grant Fellowship and a Participating Scientist Grant from the Mars Exploration Program.

7) I am also Co-I for ASU’s recently funded node of the NASA Astrobiology Institute, working with microbiologists and biogeochemists on the ASU team to characterize the geology and micropaleontology of siliceous hot spring study sites in Yellowstone National Park and sulfate evaporite sites in the Cuatro Ciengas Basin, North Central Mexico. The goal of this work is to create a geological and biosignature context for our primary study sites to create an analog context for future Mars missions (e.g. the Mars Science Laboratory mission to launch in 2011). This work is supported by the NASA Astrobiology Institute.

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