About

Dr. Rebecca Flowers

Professor, Dept of Geological Sciences, University of Colorado Boulder   

Curriculum Vitae        

I am a geochronologist who couples geochronology and thermochronology data with geologic observations to address Earth science problems. My group’s research includes:

  • Developing and refining geochronology techniques, especially (U-Th)/He thermochronology. This has included work on conventional (e.g., apatite, zircon) and novel (e.g., rutile, perovskite conodonts, pyrite) (U-Th)/He thermochronometers, and a new emphasis on innovation with high spatial resolution, laser-ablation (U-Th)/He dating.
  • Deciphering Cenozoic histories of topographic evolution to evaluate links among tectonics, mantle dynamics, erosion, and climate. These studies have focused on the carving of the Grand Canyon, the rise of the southern African Plateau, the uplift history of the Rockies and High Plains, the development of the Marlborough Fault System of New Zealand, and the topographic history of New Guinea.
  • Developing and applying “deep-time” (U-Th)/He thermochronology to decipher thermal histories over 100s of Myr to Gyr intervals.
  • Constraining the timing of ancient unconformity development (e.g., the “Great Unconformities”) and potential links with tectonic, environmental, and biologic change.
  • Determining long-term (10s-100s Ma) burial and erosion histories in continental interiors and their potential geodynamic and tectonic causes.
  • Constraining lunar impact histories using (U-Th)/He thermochronology.

Director, CU TRaIL (Thermochronology Research and Instrumentation Lab)

Our (U-Th)/He lab is the core facility of our research group. I established the lab in 2012 with support from an NSF Instrumentation & Facilities award. We have continued to expand our instrumentation with two additional NSF grants. We recently installed an ESI NWR193UC excimer laser and an KLA ZETA-20 optical profiler, and are building a custom, low-volume, He extraction and measurement line. Together this equipment is adding in situ, laser-ablation U-Pb and (U-Th)/He dating capabilities to the TRaIL.

Our lab generates thousands of (U-Th)/He analyses annually, counting >200 scientists and students among its users and regularly hosting lab visitors. We also have begun offering U-Pb analyses via LA-ICPMS. Please visit our lab website and contact me at rebecca.flowers@colorado.edu or research associate Dr. Jim Metcalf if you’re interested in obtaining data in our lab.

Our Research Team

Our group fosters a collaborative and supportive environment in which we emphasize high-quality data, careful thinking about the science problems, and clear writing. I have been fortunate to have a series of excellent students and postdocs over the years who have pushed me and our group’s science. I have also been lucky to have Dr. Jim Metcalf be the cornerstone of our lab for over a decade, as both a research associate and the TRaIL lab manager.

I am always seeking smart, creative, motivated students who are a good fit for our research team, although funding availability varies annually. If you may be interested in joining my group, please contact me at rebecca.flowers@colorado.edu. If you are a potential postdoc with initiative and project ideas, feel free to reach out to discuss possible funding opportunities.

News                         

  • April 2024: Congrats to 2024 AGeS awardees Aurora Rosenberger (WSU) and Anthony Fuentes (UC-Berkeley), who will be collaborating with TRaIL on their research projects. Aurora will use low temperature thermochronology to investigate temporal connections between normal faulting, ductile stretching, and detachment faulting in the Snake Range core complex, Nevada. Anthony will explore development of detrital hematite U/Pb geochronology.
  • April 2024: Becky and Ramon Arrowsmith (ASU), together with the rest of the AGeS3 team, are enthusiastic to announce the 22 new AGeS-Grad awardees for 2024. The projects were funded at an average award amount of $8690. Thanks to the 10-member review committee, who invested substantial time reviewing and providing feedback on every submitted proposal, and for their thoughtful discussions during the review committee meetings.
  • April 2024: Congrats to Barra Peak, who defended her PhD thesis on April 5th with flying colors! Terrific work, Dr. Peak. Barra will begin a postdoctoral fellowship at UT-Austin later this year.
  • April 2024: It was excellent to have Dr. Graham Pearson (University of Alberta) visit for two days to give a Department colloquium talk on super-deep diamonds, teach us about tuite (a high-pressure phosphate phase that can occur diamonds) during TRaIL group meeting, and discuss research. Graham is a key collaborator on our NSF-funded project on Arctic kimberlites with TRaIL PhD student Spencer Zeigler and Becky. If there is one thing that we’ve learned during this project, it’s that kimberlites are complicated beasts! Can’t help but love them.
  • April 2024: Another noble gas mass spec has moved in next door to TRaIL! The previously owned Nu Instruments Noblesse magnetic sector machine from the 40Ar/39Ar lab at the University of Vermont has been passed on to Professor Carolyn Crow in our Department. Dr. Jeff Benowitz, who was employed in TRaIL in 2022 and continues to contribute his knowledge to our group, drove the extraction line across the country and is working to set up the equipment. Jeff has extensive expertise in 40Ar/39Ar dating and Alaska tectonics. We look forward to collaborating with our new neighbor lab on projects in the future!
  • March 2024: Welcome to new TRaIL postdoc Dr. Cat Ross (PhD, UT-Austin)! Cat is funded by an NSF Postdoctoral Fellowship to work on the thermochronology of deformed accessory minerals. Cat will be working in TRaIL until she begins a tenure-track faculty position at Baylor University in fall 2025.
  • March 2024: TRaIL PhD student Connor Antonio Diaz attended the Lunar and Planetary Science Conference in Houston, Texas, where he gave a talk on his phosphate (U-Th)/He thermochronology data for Apollo 14 Melt Breccia 14311. Our colleague Dr. Carolyn Crow also attended and presented work in which Connor, Jim, and Becky are involved as part of a funded NASA project on Apollo 14 and 15 samples.
  • February 2024: Congrats to PhD student Spencer Zeigler for finishing 2nd in the CU Boulder Three Minute Thesis Competition, in which graduate students across CU-Boulder explain their thesis research in three minutes to a general audience. Way to go, Spencer!
  • January 2024: Congrats to former TRaIL PhD student Colin Sturrock on a new paper published in Minerals with coauthors Becky, Barry Kohn (University of Melbourne), and Jim. This work presents apatite (U-Th)/He data across the southern Canadian shield to decipher the regional Phanerozoic burial and erosion history, contributing to our ongoing work using (U-Th)/He thermochronology to map out continental scale burial and erosion histories to beetter constrain causative mechanisms. 
  • December 2023: Summer RESESS intern Kaden Berkhahn presented their research on the characterization of kimberlitic megacrystic zircon at the Fall AGU meeting in San Francisco.
  • December 2023: Cullen Kortynk will start as a research associate in the CU TRaIL in May 2024 to aid in streamlining our laser-ablation (U-Th)/He methods. Cullen obtained his PhD at UT-Austin, and is currently a postdoc at the University of Connecticut.
  • December 2023: Becky, Ramon Arrowsmith (ASU), and the rest of the AGeS team are enthusiastic to announce the nine 2023 AGeS-DiG (Diversity in Geochronology) awardees, who received an average amount of $16,886 for projects to mentor underrepresented groups in geochronology.
  • November 2023: Becky travelled to Tanzania for field work with Princeton colleagues Blair Schoene and Francisco Apen to explore granites, kimberlites, and quartzites of the Tanzanian craton!
  • October 2023: See our new paper in PNAS on the rise of New Guinea and the fall of Neogene global temperatures! This contribution was lead by former postdoc Peter Martin with coauthors Francis Macdonald (UCSB), Nadine McQuarrie (UPitt), Becky, and Pierre Maffre (UC-Berkeley). This study used new (U-Th)/He thermochronology in New Guinea, a palinspastic reconstruction of the Central Range, and a coupled weathering-climate model to estimate 0.6 to 1.2°C of global cooling associated with New Guinea uplift and weathering.
  • September 2023: PhD student Connor Antonio Diaz participated in the Lunar Planetary Institute’s field training and research program at astronaut training sites in Flagstaff, Arizona used by NASA for lunar mission simulations. For his PhD, Connor is funded by a NASA grant to acquire phosphate (U-Th)/He data for lunar impact melt breccias to better decipher the lunar impact history.
  • August 2023: Check out our new paper in Earth and Planetary Science Letters lead by PhD student Barra Peak with coauthors Becky and Francis Macdonald (UCSB)! This work constrains substantial Ediacaran to Ordovician (post-Snowball) erosion below the Great Unconformity across the southern Canadian Shield, indicating tectonic and geodynamic drivers for this exhumation event.
  • August 2023: The CU TRaIL is advertising for a Research Associate/Lab Technician in Geo- and Thermochronology! Funds are available to fully support the position for 5 years. Start date is flexible. Feel free to reach out to me with questions about the position. Applications will be reviewed beginning September 12, 2023 and the position will remain open until filled.
  • August 2023: Becky, Spencer Zeigler, Liam Courtney-Davies, and Barra Peak are headed to the Gordon Research Conference on Geochronology in Mt. Snow, Vermont. Spencer, Liam, and Barra presented their research, while Becky facilitated the GRC “Power Hour”.
  • August 2023: Becky is traveling to MIT for the COOL (Context of Long-term Climate and Tectonics) workshop associated with a FRES grant on which she is co-PI with Francis Macdonald (UCSB), Oli Jagoutz (MIT), Nick Swanson-Hysell (UC-Berkeley), Lorraine Liesiecki (UCSB), and John Chiang (UC-Berkeley).
  • June 2023: Welcome to summer RESESS intern Kaden Berkhahn from the University of Wisconsin Milwaukee, who is working with Spencer Zeigler, Liam Courtney-Davies, and Becky on characterizing megacrystic zircon crystals from kimberlites!
  • May 2023: Becky and Jim Metcalf are awarded a new NSF Instrumentation & Facilities grant (EAR-2311978) for 5 years of laboratory technician support! We’re excited to help advance and broaden access to laser-ablation (U-Th)/He chronology through this award.
  • May 2023: Check out our new paper lead by PhD student Spencer Zeigler with coauthors Jim and Becky in the journal Geochronology on assigning uncertainty and improving the accuracy of alpha-ejection corrections and eU concentrations in (U-Th)/He chronology. Congrats Spencer!
  • April 2023: Congrats to Sabrina Kainz for being awarded a prestigious NSF Graduate Research Fellowship! Sabrina has been an invaluable research assistant for TRaIL since last fall, after completing her honors thesis in spring 2022 in TRaIL in collaboration with Dr. Lon Abbott. Sabrina will begin a PhD at the University of Washington this fall.
  • April 2023: Congrats to Dr. Cat Ross (PhD, UT-Austin) for receiving an NSF Postdoctoral Fellowship to work in TRaIL! Cat will collaborate with Becky and Kevin Mahan on the thermochronology of deformed accessory minerals. She will join TRaIL in April 2024.
  • April 2023: Becky and Ramon Arrowsmith (ASU), together with the rest of the AGeS3 team, are excited to announce the 22 new AGeS-Grad awardees for 2023. The projects were funded at an average award amount of $8585. Thanks to the 10-member review committee, who invested substantial time reviewing and providing feedback on every submitted proposal, and unanimously agreed upon the final award list.
  • April 2023: Becky was interviewed for a geochronology article on “How do we know how old Earth is?” published in livescience.com. You can check it out here.
  • March 2023: Becky has a new paper in Geology lead by former TRaIL PhD student (now assistant prof at Univ of Idaho) Jess Stanley! It was fun writing this contribution about obtaining the first glimpse of Cenozoic erosion on the southern African Plateau from thermochronology and the implications for associated topographic uplift.
  • March 2023: Our research on the Great Unconformites was featured in a GSA Science Communication blog: “Is ‘The Great Unconformity’ a Misnomer?”  You can read it here.
  • Feb 2023: Check out our new paper in the journal Geochronology led by postdoc Peter Martin along with coauthors Becky and Jim on the calculation of uncertainty in the (U-Th)/He system. We’ll be using the HeCalc program to compute the uncertainty of our (U-Th)/He data in TRaIL moving forward.
  • Feb 2023. Becky is a coauthor on a new paper with AGeS awardee Ellen Lamont (PhD, Oregon State Univ) is now published in Terra Nova! Funded by an AGeS-Grad award, Ellen acquired (U-Th)/He data in TRaIL to constrain the timing of NW Himalayan foreland accretion, concluding it predates late Cenozoic climate change.
  • Feb 2023. Welcome to new TRaIL postdoc Dr. Liam Courtney-Davies! Liam brings laser-ablation ICP-MS, U-Pb dating, and trace element chemistry expertise to TRaIL. He comes to us from a postdoc at Curtin University and a PhD at the University of Adelaide, both in Australia.
  • Jan 2023. Becky is a coauthor on a new paper on “Neoproterozoic of Laurentia” with colleagues Francis Macdonald (UCSB), Adolph Yonkee (Weber State), and Nick Swanson-Hysell (UC-Berkeley) in the Geological Society of America Memoir on “Laurentia: Turning Points in the Evolution of a Continent”. It was fun to delve into this time interval and contribute a piece on the Neoproterozoic thermochronologic record.