Research areas
EARLY EaRTH DEPOSITIONAL SYSTEMS
Silicification
Siliceous rocks are one of the most promising deep time preservation agents – they encapsulate the earliest putative micro-fossils and microbial communities and preserve the world’s oldest known bio-signatures.
However, the depositional environment and conditions of formation for these archival silica-rich precipitates are often in dispute. They form at the intersection of hydrothermal and sedimentary processes, making their intricate diagenetic and alteration histories difficult to decipher. Our lab has several projects that combine textural and geochemical tools to investigate fundamental questions that link to how Precambrian silica-rich rocks form.
Want to learn more about our work on silicification? Check out these references: (1) https://www.sciencedirect.com/science/article/pii/S0301926820305350; (2) https://www.sciencedirect.com/science/article/abs/pii/S0016703718301017; (3) https://onlinelibrary.wiley.com/doi/abs/10.1111/ter.12192

Early Earth depositional systems
Diagenesis
To interpret primary features in Precambrian rocks, we must first determine the metamorphic and diagenetic history.
Our lab specializes in mineral paragenesis in Precambrian sedimentary and hydrothermal rocks with an emphasis on sedimentary petrology and micro-analytical geochemical techniques. We have several on-going projects in Archean greenstone belt terranes as well as Proterozoic sedimentary basins, enhanced by our regional connection to the Precambrian.
Recent graduate Sam Duncanson presented about diagenetic reactions in Paleoproterozoic iron formation at the virtual North-Central GSA section meeting (May 2020). You can view Sam’s presentation here! > https://gsa.confex.com/gsa/2020NC/meetingapp.cgi/Paper/346106

EARLY EARTH ANALOGS
Analogs
We collaborate with experts in modern hydrothermal systems.
Working in Precambrian terranes, we often utilize indirect approaches and work backwards to answer questions about ancient seawater or habitability on a nascent planet. We are fortunate to have recently begun collaborating with other scientists that work in modern hydrothermal systems to better understand processes of silicification and silica precipitation.

Science, Art and Communication
SciArt, SciComm
We have a funded project: “Involving UMD students across campus to update the museum-quality display cases in Heller Hall and connect to a modern audience” and are currently recruiting!
Project goal – The goal of this project is to involve UMD students from across campus in the re-design and renovation of the outdated museum-quality display cases on the first floor of Heller Hall.
Purpose – By updating the Heller Hall museum cases, we propose to bring the displays into the digital age and increase accessibility of the information for diverse audiences within our community. In re-designing the cases within an updated scientific framework, our goals are to improve: (1) science communication; (2) the connection between science and art; (3) diversity and accessibility of the displays.
Community impact – With the renovation we have the unique opportunity to increase public engagement with UMD by providing a free, accessible educational resource for classes, students, and the public.

Connecting with our community
Outreach
Our lab is dedicated to connecting with our local K-12 programs and broader community.
We have developed several outreach projects since the lab started in Fall 2015 and we remain committed to this goal. Check back in Fall 2021 for our shared resources (to be posted here).

PUBLICATIONS (since appointment at UMD in 2015) *student authors
Eyster, A., Brengman, L.A., Nichols, C., *Levitt, Z., *Wilcots, J., & Bergmann, K., (2021). A new depositional framework for massive iron formations after the Great Oxidation Event. Geochemistry, Geophysics, and Geosystems (G3). 22, e2020GC009113. DOI: https://doi.org/10.1029/2020GC009113
Brengman, L. A., Fedo, C. M., Whitehouse, M., Banerjee, N., & Jabeen, I., (2021). “Evaluating the geochemistry and paired silicon and oxygen isotope record of quartz in siliceous rocks from the ~3 Ga Buhwa Greenstone Belt, Zimbabwe, a critical link to deciphering the Mesoarchean silica cycle”. Invited research article, Chemical Geology, 577, 120300. DOI: https://doi.org/10.1016/j.chemgeo.2021.120300
Stewart, E.K., Brengman, L.A. and Stewart, E.D., (2021). “Revised Provenance, Depositional Environment, and Maximum Depositional Age for the Baraboo (< ca. 1714 Ma) and Dake (< ca. 1630 Ma) Quartzites, Baraboo Hills, Wisconsin.” The Journal of Geology, 129(1), pp.1-31. DOI: https://doi.org/10.1086/713687
Brengman, L.A., Fedo, C. M., Whitehouse, M. J., Banerjee, N. R., & Jabeen, I. (2020). “Textural, geochemical, and isotopic data from silicified rocks and associated chemical sedimentary rocks in the ~ 2.7 Ga Abitibi greenstone belt, Canada: Insight into the role of silicification.” Precambrian Research, Volume 351, December 2020, 105946. DOI: https://doi.org/10.1016/j.precamres.2020.105946
Brengman, L. A., & Fedo, C. M. (2018). “Development of a mixed seawater-hydrothermal fluid geochemical signature during alteration of volcanic rocks in the Archean (∼2.7 Ga) Abitibi Greenstone Belt, Canada.” Geochimica et Cosmochimica Acta, 227, 227-245. DOI: https://doi.org/10.1016/j.gca.2018.02.019
Brengman, L.A., Fedo, C. M., & Whitehouse, M. J. (2016). Micro‐scale silicon isotope heterogeneity observed in hydrothermal quartz precipitates from the >3.7 Ga Isua Greenstone Belt, SW Greenland. Terra Nova, 28.1, 70-75. doi: https://doi.org/10.1111/ter.12192
PUBLISHED REPORTS (since appointment at UMD in 2015) *student authors
Stewart, E. K., *Rasmussen, J., Skalbeck, J., Brengman, L. A., & Gotkowitz, M. (2018). Mapping the base of the Cambrian aquifer through geophysical modeling of Precambrian topography, southern Wisconsin. Wisconsin Geological and Natural History Survey Project Completion Report, 15 p.
Brengman L. A., Heins W.A., & Matthews J.A. (2016). Dissolution and Transformation of Provenance Lithotypes during Initial Sediment Generation with Application to Play-Element Prediction. ExxonMobil Upstream Research Company Research Application Report URC.2016.046, 136 p.
STUDENT ADVISEES
Graduate students supervised
- Ann Marie Prue, M.S. student (2020 – present, primary advisor). In progress, anticipated graduation 2022. Thesis project title: “Multi-method geochemical investigation of the Neoarchean Soudan iron formation, NE, Minnesota”.
- Sam Duncanson, M.S. student 2018 – 2020 (primary advisor). Thesis: “Identification of primary and diagenetic mineralogy preserved in silica-cemented horizons of the Biwabik Iron Formation, Minnesota, using petrography and electron microprobe analysis.”
Undergraduate students supervised (research projects and UROPs)
- Elizabeth Boor, Geological Sciences, B.S., (2019 – 2020).
- Heidi Krauss, Geological Sciences, B.S., (2019 – 2020).
- Emily Wojtowicz, Geological Sciences, B.S., (2019 – 2021) Senior Honors Thesis project.
- Logan Carpenter, Geological Sciences, B.S., (2019 – 2020).
- Danielle Stolze, Geological Sciences, B.S. (2019 – present). Project: “Comparative mineralogy of the ~2.7 Ga Soudan Iron Formation, Minnesota and the Deloro Iron Formation, Timmins, ON, and the Temagami Iron Formation, Temagami, ON.” https://conservancy.umn.edu/handle/11299/213805
- Kendall Johnson, Geological Sciences B.S. (2017 – 2018). Project: “Grain size distributions and mineralogy of coated grains, detrital sand and silt within the ∼1.9 Ga Mesabi Iron Range, Minnesota” https://conservancy.umn.edu/handle/11299/213998
- Anthony Wetzel, Geological Sciences B.S. (2017 – 2018). Project: “Broadly constraining Proterozoic ocean pH by determining primary and secondary carbonate mineral reactions in iron formation from the ~1.9 Ga Mesabi Iron Range, MN”
- Stephen Hanson, Geological Sciences, B.S. (2016 – 2017). Project: “A textural and mineralogical investigation of early diagenetic reactions in the ~1.9 Ga Biwabik iron formation, MN”
Undergraduate summer Research Assistants
- Katie Linderholm, Environmental Sciences, B.S., (2021 – present).
- Logan Carpenter, Geological Sciences, B.S., (2019 – 2020).
- Danielle Stolze, Geological Sciences, B.S. (2019 – 2020).
- Mady David, Geological Sciences B.S. (2018 – 2019).
- Kendall Johnson, Geological Sciences B.S. (2017 – 2018).
- Anthony Wetzel, Geological Sciences B.S. (2017 – 2018).
- Stephen Hanson, Geological Sciences, B.S. (2016 – 2017).
Research employees
- George Segee-Wright, Hamilton College, Summer/Fall 2017.
- Kendall Johnson, Spring 2020.
Graduate student committees
- Jacob Daire, Civil Engineering, M.S. (2018 – 2019).
- Kristi Kotrapu, Geological Sciences, M.S., 2017 – 2018.
- Amber Roberts, Geological Sciences, M.S., 2016 – 2018.
- Matthew Matko, Geological Sciences. M.S., 2017 – 2018.
- Margaret Upton, Geological Sciences, M.S., 2017 – 2018.
ABSTRACTS *graduate student authors, **undergraduate student authors
Eyster, A., Brengman, L. A., Ramezani, J., George, S., Bergmann, K., (2021). The first high resolution CA-ID-TIMS constraints on post-GOE Iron formation deposition. Geological Society of America, Portland Oregon (upcoming).
*Prue, A.M, Brengman, L.A., (2021). Preliminary custom iron formation calibration for a portable x-ray fluorescence instrument using the Neoarchean Soudan iron formation, Minnesota, USA. Geological Society of America, Portland Oregon (upcoming).
*Prue, A.M, Brengman, L.A., (2021). Preliminary pXRF results from Precambrian rocks of northern Minnesota. Institute of Lake Superior Geology (ILSG).
Eyster, A., Brengman, L.A., Bergmann, K., (2020). Investigating the coupling between plume volcanism and massive iron formation deposition after the rise of oxygen. (Virtual presentation Fall AGU meeting, December 8th, 2020).
*Duncanson, S.D., Brengman, L.A., Fournelle, J., Moy, A. (2020). Reconstructing Fe-silicate paragenesis using paired textural and compositional data in the ~1.9 Ga Biwabik Iron Formation, MN. North-Central Geological Society of America, May 18-19, 2020 (virtual presentation, COVID-19).
Eyster, A., Brengman, L.A., Nichols, C., **Levitt, Z., Bergmann, K.D. (2020), The tectonic context for the Gogebic Range iron formations. North-Central Geological Society of America, May 18-19, 2020 (virtual presentation, COVID-19).
**Boor, E., **Carpenter, L., **Krauss, H., **Wojtowicz, E., Brengman, L.A., Goodge, J.W., Hansen, V.L. (2020), Origin of Neoarchean metasedimentary rocks near Pike Lake, Vermilion District, Northeast, Minnesota. North-Central Geological Society of America (presentation cancelled, COVID-19).
Brengman, L.A., Stewart, E.K., **Stolze, D., **Faust, E., Wittkop, C. (2020), The role of silica in iron formations: textural, mineralogical, and geochemical comparisons from low metamorphic grade Neoarchean and Paleoproterozoic examples. North-Central Geological Society of America (presentation cancelled, COVID-19).
Brengman, L.A., Stewart, E. (2019), Textural and mineralogical characteristics of the <1710 Ma Freedom Formation compared to well-characterized, low-metamorphic grade Archean and Paleoproterozoic iron formations. PP51E-1406, American Geophysical Union.
Brengman, L.A., *Duncanson S.P., **Hanson, S., **Wetzel, A (2019). Crossing the redoxcline: an investigation into geochemical changes that directly link to textural transitions in the ~1.9 Ga Biwabik Iron Formation, MN. Geological Society of America Abstracts with Programs. Vol. 51, No. 5. doi: 10.1130/abs/2019AM-339533. https://gsa.confex.com/gsa/2019AM/webprogram/Paper339533.html
*Duncanson, S.P., Brengman, L.A., Fournelle, J.H., Moy, A (2019). Deciphering primary and diagenetic controls on mineralogy in the ~1.9 Ga Biwabik Iron Formation, MN using paired textural and geochemical analyses. Geological Society of America Abstracts with Programs. Vol. 51, No. 5. doi: 10.1130/abs/2019AM-339482. https://gsa.confex.com/gsa/2019AM/webprogram/Paper339482.html
Brengman, L. A., & Fedo, C (2018). Replacement minerals formed during alteration of volcanic rocks in the ~2.7 Ga Abitibi Greenstone Belt carry rare-earth element attributes of mixed hydrothermal fluids and seawater. American Geophysical Union Abstracts. https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/446424
Brengman, L.A., Stewart, E., Stewart, E., Moy, A., Fournelle, J., & **Segee-Wright, G. (2018) Reviving historical data >100 years later: a fresh look at the depositional setting and petrogenesis of the <1.71 ga freedom formation, Baraboo, Wi. Geological Society of America Abstracts. https://gsa.confex.com/gsa/2018AM/meetingapp.cgi/Paper/321325
Brengman, L.A., **Johnson, K., & Trower, L (2018). Grain size distributions and mineralogy of coated grains, detrital sand and silt within the ∼1.9 ga mesabi iron range, minnesota. Geological Society of America Abstracts. https://gsa.confex.com/gsa/2018AM/webprogram/Paper321622.html
Fedo, C., & Brengman, L.A. (2018) Geochemistry of multiple carbonate units from the ~3.7 ga isua greenstone belt, sw greenland. Geological Society of America Abstracts. https://gsa.confex.com/gsa/2018AM/meetingapp.cgi/Paper/321151
*Drazan, J., Brengman, L.A, & Fedo, C (2018). Preliminary petrographic and geochemical investigation of silicified volcanic rocks and silica-rich exhalative rocks from the ~2.7 Ga Abitibi Greenstone Belt, Canada. Institute of Lake Superior Geology (ILSG) Program and Abstracts.http://flash.lakeheadu.ca/~pnhollin/ILSGVolumes/2018%20ILSG%20Program%20and%20Abstracts.pdf
Stewart, E., Skalbeck, J., **Rasmussen, J., Gotkowitz, M., Brengman, L.A., **Segee-Wright, (2017) G. Developing a geologic framework for aquifer geometry through modeling of gravity and aeromagnetic data. (American Water Resources Association, Wisconsin Section Annual Meeting, Appleton, WI)
Brengman, L. A. (Author & Presenter), Fedo, C.M., Whitehouse, M.J. (2016), American Geophysical Union, “Textural and isotopic evidence for silica cementation in ~1.88 Ga Granular Iron Formation,” San Francisco, California, United States. (December 12, 2016).
Brengman, L. A. (Author & Presenter), Larson, P., **Hanson, S. (2016), Geological Society of America, “A textural and mineralogical investigation of early diagenetic reactions in the ~1.88 Ga Biwabik iron formation, MN,” Denver, Colorado, United States. Geological Society of America, Abstracts with Programs. v. 48, n. 7. (September 25, 2016).
Brengman, L.A., Fedo, C. M., Whitehouse, M. J. (2015) Micro-scale silicon isotope heterogeneity observed in hydrothermal quartz precipitates from the >3.7 Ga Isua Greenstone Belt, SW Greenland. Geological Society of America, Abstracts with Programs, Annual Meeting, Baltimore, MD, v. 47, n. 7, p.786.