Dawn’s Research Group

Follow Our Research:

    Dawn’s Twitter, Dawn in Antarctica blog, Dawn on Mars blog, and Sumnerd’s videos

    Tyler’s Cyanobacterial Adventures and PLRP & Mars Life blogs

    CrustaMars’ videos

    KeckCAVES and SpelunkerUCD videos


Cara Harwood - Ph.D. student, studying Cambrian thrombolites

Tyler Mackey - Ph.D. student, studying microbial mats in Antarctica

Amy Williams - Ph.D. student, studying biosignatures in Fe-S weathering environments

Kate Wall - Ph.D. student, studying the genetics of microbial mats in Antarctica

Megan Kursor - Ph.D. student, studying the genetics of microbial mats in Antarctica

Marisol Juarez Rivera - M.S. student, studying the morphology of fenestrate microbialites

Athena Phan - Undergraduate, studying porosity and permeability in gossan with iron-oxide coated filaments

David Barasch - Undergraduate, serial sectioning microbialites

Sasha Leidman - Undergraduate, using GIS and historical data to reconstruct lake levels for Lake Joyce, Antarctica

Current Students

Tyler Mackey completed his M.S. in spring 2012.  He worked on Antarctic microbial mats and is continuing the project as a Ph.D. student working with me.

Thesis Title:  Initiation of branched growth in conoform stromatolites as a response to microbial community and water depth changes in Lake Joyce, Antarctica

Cara Harwood completed her M.S. in 2009.  She worked on Beck Spring microbialites, interpreting community differences based on stratigraphy, facies analysis, and petrography.

Thesis Title: Multiple origins of diverse microbial fabrics in co-occurring thrombolitic and stromatolitic structures from the Neoproterozoic Beck Spring Dolomite.

Rebekah Shepard completed her Ph.D. in spring 2009. She worked on the morphology of microbial communities and cyanobacterial motility influences morphology for her Ph.D. thesis. She also characterized microbial communities in Lake Pavillion, B.C.

Thesis Title: The Significance of Cell Motility to Microbial Community Morphogenesis

James Bishop (M.S. 2004) completed his Ph.D. in Winter 2008 with Isabel Montanez, Dave Osleger and me. He is currently working as a geologist at Chevron, San Ramon, CA. 

Thesis Title: Sedimentation and Diagenesis During the Late Paleozoic Ice Age: Arrow Canyon, Nevada, and the Capitan Backreef, Slaughter Canyon, New Mexico.

Greg Chavdarian completed his M.S. degree in Spring 2008. He characterized cracking mechanisms in sand at White Sands National Monument and studied the enchange of water vapor between the sand and the atmosphere. He is currently working as an astronomy tour guide in Hawaii. 

Thesis Title: Polygonal Cracks and Mineral-Atmospheric Water Cycling in Hydrous Sulfate Sands: An Analog to Martian Outcrops.

Nik Huerta finished his M.S. thesis in Winter 2007 on neutron CT imaging techniques at McClellan Nuclear Radiation Center after completing his senior thesis in December 2003. His focused on developing methods for evaluating porosity in sandstones, including using computational and mathematical approaches to evaluating images. Nik earned a masters in petroleum engineering at UT Austin, and is now working on a Ph.D.. 

Thesis Title: Neutron Computed Tomography and Porosity in Geologically Relevant Samples.

Megan Murphy completed her Ph.D. in Fall 2006 on microbial tube structures, fenestrate microbialites and facies in the Neoarchean Carawine Formation, Western Australia. Megan will start an internship at Chevron in the San Ramon Carbonate Research Group in February 2007.

Thesis Title: Variations in Microbialite Morphology with Depositional Environment in a Precambrian Ramp Deposit, Hamersley Group, Western Australia.

Maris Tabor completed her M.S. thesis in 2004 on neutron CT imaging techniques at McClellan Nuclear Radiation Center. Her focus was on calibrating the attenuation characteristics of carbonates and organics to image ancient microbial structures. 

Thesis Title: Applications of Neutron Computed Tomography for 3-D Imaging of Microbial Structures in Archean Carbonates.

James Bishop finished his M.S. thesis in Winter 2004. He continued his research as a Ph.D. student at UCD and now works for Chevron. See his papers on the origin of molar-tooth structures

Thesis Title: A New Model for Molar Tooth Structure, Facies, and Stratigraphy of the Neoarchean Monteville Formation, Transvaal Supergroup, South Africa.

Kat "Phoenix" Perkins (once Bergk) finished her M.S. thesis in Spring 2003. May Kat's new feathers remain strong and beautiful for years to come! 

Thesis Title: Sequence Stratigraphy of a Portion of the Lower Cambrian Grand Cycle C, Southwestern Nevada and Southeastern California.

Nat Stephens finished his Ph.D. thesis in Spring 2002 on Late Devonian microbial reefs and carbon isotopes of the Canning Basin, Australia. Nat is currently working as a geologist for ExxonMobil.

Thesis Title: Late Devonian Stratigraphy, Stable Isotopic Analyses, and Paleoecology in the Napier, Oscar, and Emanuel Ranges, Canning Basin, Western Australia.

Sarah Tourre finished her M.S. thesis in Fall 2000 on Eocene herringbone calcite. Last I heard, Sarah is working as a Staff Geologist in the environmental consulting industry.

Thesis Title: Cave-Filling Herringbone Calcite: Morphology and Geochemistry of an Unusual Carbonate Cement from Egypt.

Former Graduate Students

Undergraduates Who Have Worked with Me

Marisol Juarez Rivera (2013) studied the morphology of fenestrate microbialites.  She submitted a paper, Unraveling the three dimensional morphology of Archean microbialites to theJournal of Paleontology, special issue: Virtual Paleontology.  She is now a M.S. student in our lab.

    Thesis Title: Unraveling the three dimensional morphology of Archean microbialites

Rebecca Rodd (2013) serial sectioned and studied microbialites, but then did a senior thesis with Ken Verosub through the Keck program.

Alexandria Hernandez (2012) - Undergraduate, studied microbial mat morphology

Alicia Noel (2012) investigated the composition of dark sand in Gale Crater, Mars.

Jane Elliot (2012) logged microbial structures in Tyler’s underwater video of mats in Antarctic lakes.

Anahita Yadzi - briefly studied Mars visualization using Crusta before moving on to engineering projects.

Brook Contantz (2011) studied the morphology of thrombolites using KeckCAVES software.

Christopher Haley (2011) helped us greatly with Mars visualization using Crusta.  He figured out how to process HiRISE data into Crusta.  He is starting graduate school in aeronautical engineering at UCLA in fall 2011.

Lauren Dolezal (2009) did a senior thesis on reconstructing the 3D morphology of thrombolites using KeckCAVES software. She worked very closely with Cara.
    Thesis title: 2D and 3D Analysis of Thrombolites: Stromatolite Diagenesis or Originally Clotted Texture

Eric Stevens (2009) did a senior thesis on reconstructing the 3D morphology of fenestrate microbialites using KeckCAVES software. He presented a poster on this work at AGU 12/2009. He is starting graduate school at U Minnesota in fall 2011.
    Thesis Title: Microbialites in 2D and 3D

Natalie Stork (2008)worked with Bekah on cyanobacterial motility. She also spent a year in New Zealand working with Cathy Cambell! Natalie is now in graduate school at the University of Connecticut.
    Thesis Title: CaCO3 Precipitation in Freshwater Biofilms Dominated by Oscillatoria sp.

Dominique Waters (2009) researched the water quality of the Arboretum Waterway in collaboration with the course Geology of Campus Waterways. She was a math major and is currently pursuing a M.S. degree.

Patrick Senge (2006) worked with Megan Murphy on reconstructing the 3-D geometry of tube structures from Neoarchean carbonates using serial sectioning. Patrick is now a mine geologist working in Nevada.
    Thesis Title: Development of the Late Archean Microbialite Support and Drape Structures of the Gamohaan Formation, Transvaal Supergroup, South Africa

Greg Chavdarian (2005) worked and is working on understanding how cracks and fins in sulfate sands form on earth and on mars. Here are links to his thesis (220 KB pdf) and figures (14 MB pdf).
    Thesis Title: Cracks and Razorbacks: Pieces of Mars at White Sands National Monument, New Mexico.

Katie Alexander (2005) wrote a Senior Thesis investigating how cyanobacterial mats respond to water flow and how they bind sand-sized sediment. She created "Microbially Induced Sedminary Structures" in the lab. She worked closely with Bekah and is now in graduate school at ASU.

    Thesis Title: "MISS" in a Laboratory Setting: Observations and Mechanisms of Formation.

Gina Lee (2004) worked on characterizing erosion of Cache Creek near Guinda, CA for her thesis. She worked in environmental consulting for a while and then returned to school, earning a M.S. from San Francisco State and now working toward a Ph.D. at UC Santa Barbara.
    Thesis Title: Thirty-nine Years of Cache Creek Migration and Embankment Erosion

Nik Huerta (2003) worked on developing neutron imaging techniques at McClellan Nuclear Radiation Center and applied them to studies of porosity and organic compounds in rocks (Abstract of his AAPG poster presentation). He continued this research as a masters student at UCD and is now in a petroleum engineering masters program at UT Austin.
    Thesis Title: Neutron Computed Tomography: A Characterization of the System at McClellan Nuclear Radiation Center and Presentation of Groundwork Research for Use in Sedimentary Geology.

Jason Snyder (2002) graduated spring 2002 after working on the stable isotopic geochemistry of Egyptian herringbone calcite. Jason just finished a M.S. in atmospheric sciences at UCDavis.
    Thesis Title: Determination of Calcite Age through Paleoclimatology.

Marie Reil graduated fall 2001. She worked on compiling the geology of Shell Ridge in Walnut Creek, CA. She is working in water quality these days.

Tracy Fenger (2000) wrote a thesis on the Neoproterozoic Rainstorm Member of the Johnnie Formation (Abstract of her GSA poster presentation). Tracy also helped with my calcite precipitation experiments. After working for an environmental consulting firm for several years, she earned a graduate degree paleoclimatology at UNC Department of Geological Sciences.
    Thesis Title: A Glacial Interpretation of the Rainstorm Member of the Johnnie Formation, Eastern California