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| Research My research is focused on the history of microbialites. Microbialites are sedimentary structures that are built by microbes, mostly bacteria or algae. The sedimentary aspect can either be from in situ cementation by the microbes or from trapping of grains. There are many different shapes and forms of microbialites. The most common form are "stromatolites" or layered microbialites. A form most common in the Cambrian and Ordovician is the "thrombolite" which is recognized by its clotted texture. Another type of microbialite that I am interested in is the "dendrolite" which is neither laminated or clotty, but is composed of a dendritic pattern produced by calcified microbes. Little is known about dendrolites, but they are found in Cambrian and potentially Devonian rocks. I am interested in how these various forms are distributed in time and space and what sedimentological, ecological, and environmental factors are crucial for their development. |
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| How did I get into this research direction? I was fortunate in my nebulous youth to have a mentor, Robert Dill. Bob Dill was the guru of marine geology and invited me to work with him on submarine canyons in San Diego. About this time, he discovered living stromatolites in the Bahamas and asked me to join him. Now, if you were 17 and invited to go to the Bahamas, SCUBA dive in 80 degree water, bask in the Caribbean sun, wouldn't you be hooked? Captain Bob passed away last year but his legacy in geology will last for many generations and he is much missed. | |||||||||||||||||||
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Currently, I have active research in four areas. First, the wonderful Tepee Buttes of Colorado. These carbonate mounds were built by microbes feeding off of methane that was seeping through the sea floor. These types of buildups are well-known from the recent and have been described from ancient settings. The Tepee Buttes are some of the best exposed methane-seep carbonates in the fossil record. My colleages in this endeavor are Karla Parsons-Hubbard (Oberlin College) and Timothy Lyons (University of California, Riverside). | ||||||||||||||||||
| Second, I have started a new project in the Mesabi Iron Range of northern Minnesota, trying to understand the beautiful stromatolites of the Biwabik Iron Formation. These lovely structures yield important clues to the environments the iron formation was deposited in as well as insight into the paleobiology of the Earth two billion years ago. Noah Planavsky, a student at Lawrence University, is working with Ali Cordie (Senior at Gustavus) on this project. We are also getting lots of help from the microscopy wizards at Thin-Films Technology. |  |
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Third, I am working with Julie Maxson (Research Associate at Gustavus) on travertine, tufa, and oncoids from the Lower Cretaceous Cedar Mountain Formation of Utah. Julie kindly asked me to join her on her REU project in 2004 and wouldn't you know it? I found microbialites! Finally, I will never turn my back on my true love, the Cambrian of the Great Basin! I am working on a project with Stanley Awramik (University of California, Santa Barbara) on some silicified microfossils from the Upper Cambrian. I am also continuing to work on various aspects of Cambian reefs with Melissa Hicks (University of Nevada, Las Vegas) and Tom Anderson (Sonoma State University). If you are interested in learning more about my research, or are a student and wish to join in, please send me a note. |
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Mesabi Range Geologic Society Recent Publications: Joseph Beer: “Age and Depositional Setting of the ‘Blue Earth Siltstone’, Minnesota River Valley” (2003) Melissa Hicks: “Development of a Sequence Stratigraphic Framework for the Upper Nopah Formation (Upper Cambrian, Eastern California and Western Nevada)” (2002) Robyn Howley: “Carbonate Depositional History Refined by Gamma Radiation Analysis: Middle to Lower Upper Cambrian Highland Peak Formation, Eastern Nevada” (2002) Treasure Bailey: “Using Dendrolite Morphology to Correlate Upper Cambrian Formations in the Delamar and Spring Mountains, Southern Nevada” (2002) Christopher Gale: “A Petrographic and Scanning Electron Microscopic Investigation of Fossil Bacteria in the Late Campanian Aged Tepee Buttes of Pueblo County, Colorado” (2001) Peter Taylor: "SEM and Petrogaphic Investigation of Stromatolites Associated with Coal Seams, Cape Breton Island, Nova Scotia" (2000) Jennifer Slepian: "Paleoecology of Silurian Corals, Eastport, Maine" (2000) Rosie Myers: "Growth History of a Pleistocene Reef, Exuma Islands, Bahamas" (2000) |
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