Fluid-Rock Geochemistry and Biomineralogy
My interests involve reactive fluid flow and mineralization in sedimentary and volcanic systems in both ancient and modern environments, as well as microbially mediated reactions at the earth's surface. I primarily focus on the geochemistry of mass extinctions and the role of tectonics in shale gas development (particularly during the late Devonian), and the geomicrobiology of cave deposits. I also work on the geochemistry of the Engare Sero Footprint Site in Tanzania.
My research involves a variety of techniques such as CL (cathodoluminescence), scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction, Fourier Transform Infrared Spectroscopy (FT-IR), and stable isotope analysis (particularly strontium, carbon and oxygen). My current field areas include Tanzania, western China, western Mongolia, east Tennessee (USA), and caves in the southern Appalachians.
Research GroupsFor the last six years, I have worked extensively with Dr. Suzanna Bräuer in the Department of Biology, and Dr. Cara Santelli at the Smithsonian Natural History Museum on manganese oxide biominerals produced by both bacteria and fungi. We do extensive fieldwork in southern Appalachian caves as well as on a variety of regional rocks at the surface that have experienced reactive fluid flow and/or biomineralization. For more information about our geomicrobiology research group, visit http://geomicrobiology.appstate.edu.
Since 2011, I have worked with the UNESCO-funded International Geoscience Programme Project 596, which studies climate change and biodiversity in the mid Paleozoic. My main collaborators include paleontologists Dr. Johnny Waters (Department of Geology) and Dr. Erika Kido (University of Graz, Austria), and stratigrapher Dr. Thomas Suttner (University of Graz, Austria). We work primarily in the Central Asian Orogenic Belt (western China and western Mongolia) and in Europe to determine the extent and scope of Devonian ocean anoxia events, and the rebound from the mass extinctions associated with these events.
News and Updates
- Feburary 2014 - Recent work by the Waters-Carmichael Devonian research group now in press: A New Model for the Kellwasser Anoxia Events (Late Devonian): Shallow Water Anoxia in an Open Oceanic Setting in the Central Asian Orogenic Belt, Palaeogeography, Palaeoclimatology, Palaeoecology (DOI:10.1016/j.palaeo.2014.02.016)
- December 2013 - Hot off the presses, all the things you (never?) wanted to know about human feces in caves, and the interplay with manganese oxide mineralization! Evidence of Sustained Anthropogenic Impact in Carter Saltpeter Cave, Carter County, Tennessee, Journal of Cave and Karst Science
- December 2013 - Sarah's work on the geochemistry of mass extinctions in the Late Devonian (a collaboration with Dr. Johnny Waters and a UNESCO-sponsored team of international researchers) highlighted in Science Daily.
- August 2013 - Sarah traveled to Kunming, China to participate in the NSF- and CNSF-sponsored Sino-US Critical Transitions Workshop: History of Life Evolution in Critical Geological Periods workshop. She presented her collaborative work with Dr. Johnny Waters on the geochemistry of the Frasnian-Fammenian extinction.
- April 2013 - Sarah receives the Wayne D. Duncan Faculty Enrichment and Teaching Fellowship for Excellence in Teaching in General Education
- April 2013 - Congratulations to Josh Feierstein '15 for his research award at the 16th Celebration of Student Research and Creative Endeavors
- March 2013 - Recent work by the Carmichael-Bräuer geomicrobiology research group now in press: Mn(II)-oxidizing bacteria are abundant and environmentally relevant members of ferromanganese deposits in caves of the upper Tennessee River Basin (Geomicrobiology Journal).
- March 2013 - Sarah receives grant to study the geochemistry of an early human footprinted ash in Tanzania from the Appalachian State University Board of Trustees
- January 2013 - Sarah receives ShaRE grant to study biological Mn oxidation via TEM-EELS microscopy at Oak Ridge National Laboratories
- June 2012 - Congratulations to Leigh Anne Roble '12 and Aubry DeReuil '13 for presenting their research at the V.M. Goldschmidt Conference in Montreal, QB, Canada.
- April 2012 - Congratulations to Leigh Anne Roble '12 and Aubry DeReuil '13 for winning awards for their research at the 15th Annual Celebration of Student Research and Creative Endeavors
- December 2011 - Carmichael-Bräuer geomicrobiology research group's work on microbial biominerals spotlighted in the Appalachian news
- April 2011 - Sarah receives grant to study biominerals from NC Space Grant New Investigator's Program