Welcome!
In the Wisconsin ICP-TIMS lab, we study how the Earth became a habitable planet, from the origin and evolution of the earliest continents to the development of an oxygen-rich atmosphere. Our primary tools are radiogenic isotopes in rocks and minerals, which we use as chronometers and tracers in conjunction with stable isotope and geochemical compositions. We are also actively working on geochemical analytical technique development in order to expand the range of questions we can ask. Please refer to our Research page to learn more.
Recent News
May 2025: Geosci 457, co-taught by Shanan Peters, Phil Brown, and Annie, returned from another spectacular year mapping deformed sediments of the Huronian Supergroup in Ontario, Canada.
April 2025: Esther Stewart defended her PhD thesis, “Sedimentologic and geochemical markers of marine incursion to the interior Laurentian Oronto Group basin at ca. 1.08 Ga.” “Oront”ulations, Dr. Stewart!
Former post-B.Sc. student Abby Santis has been awarded a 2025 NSF GRFP in support of her PhD research at Washington University. Way to go, Abby!
February 2025: Our recent clean lab renovations are complete, just in time to welcome visiting undergraduate researcher Josh from Middlebury College. Congrats to PhD student Emily Palmer for passing her Thesis Background Exam in the Department of Chemistry, and to former PhD student Emily Mixon for featuring in a recent article by CAMECA highlighting her collaboration with WiscSIMS for work focused on assessing which tectonic environments were operative on the early Earth.
January 2025: PhD student and collaborator Research Scientist Tyler Blum are analyzing O isotopes in detrital zircons from the Jack Hills.
October 2024: Annie visited colleagues at Carleton College and got a tour of local business facades made of the 3.5 Ga Morton Gneiss!
September 2024: Former PhD student Emily Mixon has a new paper out in PNAS, “Geochemistry from Earliest Evolved Terranes Records Coeval Stagnant- and Mobile-lid Tectonic Regimes.” Please contact Emily (eemixon@wisc.edu) or Annie with questions.
Congrats to collaborator Lexie Millikin on the successful defense of her PhD thesis at Yale University, “Timing, Tempo, and Drivers of Proterozoic Environmental Change: Insights from the Empirical Record.” Lexie has a paper out in Geology, “A new Re-Os age constraint informs the dynamics of the Great oxidation Event,” available here.
Esther and Annie joined collaborators Kenz Carlton and Basil Tikoff for fieldwork in late Archean orthogneisses and amphibolites of the Upper Peninsula of Michigan. Kenz will be constructing a geologic map of these rocks.
Our clean chemistry lab is currently under construction and will be completed soon.
Students Em Palmer and Hanna Konavaluk presented research posters at the Wisconsin Center for Origins Research (WiCOR) on September 20th.
August 2024: Welcome to incoming PhD student, Rowan Gregoire! Rowan comes to our group from Dartmouth University, where he did undergraduate research under the direction of Prof. Brenhin Keller.
Emily Mixon defended her PhD thesis, “Characteristics of Archean Crustal Reworking: Insights from in-situ Zircon δ18O and Trace Elements” on August 16, 2024. This month, Emily started a permanent research position working with Professor Andrea Dutton in the SLEUTh lab, UW-Madison Department of Geoscience.
Annie will be at Goldschmidt in the following capacities: 1) research talk, “Coeval stagnant- and mobile-lid tectonic regimes in the Eoarchean,” in session 3fO1; 2) as the MC at lunch sessions “Career Paths in Geoscience: Personal Perspectives” on Monday and “How to set up a lab” on Wednesday; and 3) as a co-convenor for the Early Earth Processes: Crust-Mantle evolution in the Hadean and Archean Eons session (3fP1, 3fO1, and 3fO2).
Bon voyage to researcher Abby Santis, who is headed to WashU to start a PhD in the fall. We will miss you!
July 2024: Hanna Konavaluk, Annie, and collaborators Zach Adam (UW-Madison) and Laurie Zielinski (Dartmouth) conducted fieldwork in the Belt Supergroup, Montana. Along with collaborator Sarah Slotznick (Dartmouth),we are working on an NSF-funded project focused on the geochemistry, provenance, stratigraphy, and paleobiology of these rocks and are excited to get moving on our analytical work this fall.
Wonderful news for the Gabon and Oxygenation of Earth Drilling Early Earth Project (GOE-DEEP) team; we have received official support from the International Continental Drilling Program to move forward with our project studying the sedimentary record in Franceville, Gabon. We are now working to obtain matching support from the member countries and hope to move ahead with drilling next year. Annie is the Co-Investigator of the Geochronology theme.
Congrats to collaborator Mingming Zhang on publication of his paper, “Forging inner-disk Al-rich chondrules by interactions of CAI-like melt and ambient gas.” Mike Tappa and Mingming used the QQQ-ICP-MS and LA-ICP-MS in our lab to measure the elemental compositions of chondrules. The paper can be freely accessed at this link through August 25, 2024.
June 2024: Congrats to Hanna Konavaluk on her receipt of a GSA Grad Student Research Grant.
April 2024: A special congratulations to PhD student Hanna Konavaluk and Post-BSc researcher Abby Santis on their receipt of 2024 NSF GRFP Honorable Mentions! And a further congrats to Hanna Konavaluk on her receipt of a Tobacco Root Geological Society 2024 Field Scholarship for her upcoming fieldwork.
Also, congrats to PhD student Emily Mixon on her receipt of the 2024 Distinguished Graduate Student Award in the UW-Madison Department of Geoscience and undergraduate researcher Alissa Choi on her receipt of the 2024 Outstanding Sophomore Award in the UW-Madison Department of Geoscience. Rock on!
A hearty welcome to baby Adelaide, the 6th ICP-TIMS Geobadger baby since 2021!
March 2024: Congrats to Middlebury College collaborators Jeff Munroe, Abby Santis, and Elsa Soderstrom on the publication of, “Mineral dust and pedogenesis in the alpine critical zone,” in SOIL. As part of their BSc senior theses, Abby and Elsa traveled to our lab and conducted Sr and Nd isotope measurements.
February 2024: Welcome to incoming PhD student, Emily Palmer! We are delighted to have her join us from the UW-Madison Department of Chemistry. Emily will be taking on a variety of U-Th-Pb projects focused on atmospheric evolution and crustal evolution.
January 2024: Annie participated in a wonderful teaching workshop, The Discussion Project. The focus of the workshop was to promote thoughtful and inclusive discussions in group spaces. It is run by UW-Madison and graduate students, staff, and faculty can participate!
December 2023: Congrats to PhD student Esther Stewart on the publication of “End-Mesoproterozoic (ca. 1.08 Ga) epeiric seaway of the Nonesuch Formation, Wisconsin and Michigan, USA” in GSA Bulletin with coauthor Tony Prave. The article can be accessed here.
At the 2023 AGU Fall Meeting, Annie has an invited oral presentation, “The Acasta Gneiss Complex, Canada, as a cornerstone for early tectonic models,” and ICP-TIMS lab collaborator Cat Ross has a poster, “U-Pb dating of mineralized fault systems in the Rio Grand Rift.”
November 2023: Congrats to PhD student Emily Mixon on the publication of “Mechanisms for generating elevated zircon δ18O in Archean crust: Insights from the Saglek-Hebron Complex, Canada” in EPSL with coauthors Jonathan O’Neil, Hanika Rizo, Tyler Blum, John Valley, and Chloe Bonamici. Here is the share link for free access to the article.
September 2023: Welcome, incoming PhD student Hanna Konavaluk and post-BSc researcher Abby Santis. We’re happy to have you as part of our team.
Congratulations to collaborator Leah Evans, who was the featured textile artist in this recent article from the Cap Times. Leah will be teaching a workshop, “Science in Quilting,” at the Great Wisconsin Quilt Show on September 8 and 9, 2023, and will be joined by our collaborator and outreach expert at the UW Geology Museum, Brooke Norsted.
August 2023: PhD student Emily Mixon will be presenting an invited talk at the 2023 Gordon Research Seminar in Geochronology, “Evaluating zircon trace element proxies for Archean tectonic provenance using suites of cogenetic zircon from the Acasta Gneiss Complex” (abstract: GRC-Abstract-Mixon) and a poster at the 2023 Gordon Research Conference (GRC) in Geochronology. Annie is a co-Vice Chair of the GRC and will be serving as the Discussion Leader for the “Growth and Stabilization of Continents” session and will also be presenting a poster. Annie will be co-Chair of the next GRC in Geochronology in 2025 in Sunday River, Maine; hope to see you there!
July 2023: There are several new babies born within the families in our lab in 2023– welcome to the newest Geobadgers: Alec, Emelia, and Scotty!
Annie will be giving an invited presentation at Goldschmidt 2023 and would be pleased to meet with potential postdocs and graduate students.
March 2023: Congratulations to former MSc student, Khalil Droubi, on the publication of his first paper, “U-Th-Pb and Trace Element Evaluation of Existing Titanite and Apatite LA-ICP-MS Reference Materials and Determination of 208Pb/232Th-206Pb/238U Date Discordance in Archaean Accessory Phases,” in a special volume of Geostandards and Geoanalytical Research.
November 2022: Athena and Annie attended the GOE-DEEP ICDP workshop in Trondheim, Norway.
October 2022: We are mourning the loss of our dear friend and colleague, Frank Dudás. We will miss your corny jokes, unsurpassed expertise in mineral identification, and philosophical musings.
The UW Earth Evolution Group is at GSA! The following researchers are presenting:
–Athena Eyster (Sunday AM poster, “A synthesis of new structural, stratigraphic, and geochronologica constraints from NE Washington with implications for Neoproterozoic Snowball glaciations.”)
–Emily Mixon (Tuesday PM poster, “Early and variable contributions from supracrustal rocks in Archean magmas from the Saglek Block, Labrador, Canada.”)
–Khalil Droubi (Wednesday AM talk, “Tectonothermal evolution of the southern Laurentian margin from the Neoarchean to the Paleoproterozoic recorded in the Watersmeet Gneiss Dome, MI, USA.”)
–Annie Bauer (1- Sunday PM mentorship presentation in the Women in Geology Reception; 2- Wednesday AM talk: “Establishing a robust temporal framework for the Paleoproterozoic Lomagundi-Jatuli carbon isotope excursion in the Francevillian Basin, Gabon.”)
–collaborator Cailey Condit (Tuesday AM poster; “Petronet: A petrology and high-temperature geochemistry community built within an antiracist and inclusive network”)
–collaborator Clay Kelly (Sunday AM talk; “Icthyolith Nd isotope compositions suggest southerly incursion of boreal water mass along eastern margin of Western Interior Seaway during Campanian cooldown.”
June 2022: Congrats to Khalil Droubi, who defended his MSc on June 30th, and collaborator Joe Hayes, who also defended his MSc thesis on June 14th. PhD student Emily Mixon passed her preliminary exam and is officially a dissertator, well done!
May 2022: Congrats to Sally Stevens, who defends her MSc on May 20th. An AGU Advances article led by collaborator Prof. Nadja Drabon, “Destabilization of long-lived Hadean protocrust and the onset of pervasive hydrous melting at 3.8 Ga,” is available here. PhD student Esther Stewart is officially a dissertator, well done!
February 2022: Check out this recent article in Eos by colleague Alka Tripathy-Lang quoting a variety of Precambrian geochronologists (including Annie) regarding the difficulties in dating Precambrian rocks, especially sedimentary successions.
January 2022: Welcome to incoming researcher, Athena Eyster! Congrats to PhD student Emily Mixon on her recent 40Ar/39Ar methods paper following on her work in Prof. Brad Singer’s lab.
August 2021: Congrats to PhD student Emily Mixon for her receipt of the 2021 Lawrence A. Taylor Research Fund Award and a 2021 GSA Graduate Student Research Grant. Congrats to MSc students Khalil Droubi and Sally Stevens for their receipt of 2021 GSA Graduate Student Research Grants, as well!
July 2021: Annie is giving a keynote, “Zircon Hf isotopic evidence for the gradual onset of Earth’s mobile-lid tectonic regime,” in Session 3h (Formation and evolution of continental crust in the Precambrian: Linking Earth’s surface and deep interior) at Goldschmidt. Please check it out!
April 2021: Congrats to PhD student Esther Stewart for her receipt of the UW Geoscience Solien Assistantship and the 2021 Twenhofel Award– keep up the good work. Also congrats to visiting student Pan Hu for the acceptance of his recent paper on the Qinling orogen in Lithos and his upcoming PhD defense!
March 2021: In our group, we are invested in tackling gender and intersectionality bias issues in STEM. From Friday, March 12, through Sunday, March 14, the University of Wisconsin will be hosting the screening of the documentary Picture a Scientist, which highlights the struggles of three famous female scientists in the sciences. The screening will be followed by two panels on Monday, March 15 – one for faculty, staff, and postdocs at noon, and a second panel for all graduate and undergraduate students at 4 pm. If you are a UW employee or student, you can register to watch the film and/or attend a panel at this link.
December 2020: Our group at AGU 2020: Check out the “Ancient Earth Evolution: From Magma Ocean Solidification Through the Archean” oral D1022 + poster D1020 session, convened by Brad Foley, Natasha Barrett, Jesse Reimink and Annie Bauer. Also check out Annie (PP020-03 – Os and Nd isotope constraints on Paleoproterozoic global events as recorded in sediments from Russian Fennoscandia), Emily (V036-09 – Optimizing 40Ar/39Ar analyses using an Isotopx NGX mass spectrometer), and collaborator Nadja’s (DI022-04 – Destabilization of Long-Lived Hadean Protocrust and Onset of Pervasive Hydrous Melting at 3.8 Ga Recorded in Detrital Zircons of the Green Sandstone Bed, South Africa) talks.
September 2020: Welcome to our incoming students: Khalil Droubi, Sally Stevens, and Emily Mixon. We’re so glad to have you on our team.
May 2020: A huge congrats to our outgoing senior undergraduate thesis researchers, Sheila Abdul Rashid and Liv Parsons!
April 2020: A recent paper from our group is mentioned at the end of this well-written article in National Geographic by Maya Wei-Haas describing the results of a new study that documents a 3.2 Ga continental plate rate consistent with modern plate tectonics. Congrats to our colleagues at Harvard and their coauthors!
We have a new paper out, “Hafnium isotopes in zircons document the gradual onset of mobile-lid tectonics” (Bauer and Reimink et al. 2020) in Geochemical Perspective Letters, which is an open-access publication. You can read it here.
March 2020: The University of Wisconsin-Madison campus has shut down all non-essential research activities in response to the coronavirus epidemic. Our lab facilities are currently closed but we hope that we will be able to reopen soon.
January 2020: Adina Paytan (UCSC) is visiting our department as part of the Voices of Geowomen series, including a women+allies dinner, a Diversi-tea about the imposter syndrome, and a science talk.
Welcome, incoming PhD student Esther Stewart and visiting student Pan Hu!
December 2019: Annie is presenting at AGU in San Francisco; Poster V31G-0135.
October 2019: We are looking to recruit new graduate students for the upcoming academic year! Please see Join Our Group for more information.
September 2019: Our lab is currently under construction to accommodate a new Quadrupole instrument. More details and photos to follow.
