DEPARTMENT OF EARTH AND PLANETARY SCIENCES

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Research

My research group seeks to better understand how the fundamental coupled components of the Earth system—the atmosphere, biosphere, hydrosphere and solid Earth—interact to regulate the chemical composition of the ocean-atmosphere system and how this has changed over the past ~1 billion years.  In particular, we focus on identifying the complex set of processes that regulate the global carbon cycle and the evolution of Earth’s climate system.  My research is driven by three questions:

When did oxygen concentrations in the ocean-atmosphere system rise to near modern values, and how and why have these levels varied through the past one billion years?

How do variations in oxygen levels in the past relate to extreme climate change (e.g.,glaciation) and the evolution and diversification of macroscopic organisms?

How have past changes in ocean chemistry affected the way in which the Earth system operates to regulate the global carbon and oxygen cycles?

To answer these questions, we study modern and ancient sedimentary systems, integrate field observations with a variety of geochemical tools (mostly stable isotopes), and combine these efforts with simple geochemical models.

Teaching

EARTH 105: Climate Catastrophes in Earth History
EARTH 203: Earth Systems History
EARTH 312: Stable Isotope Geochemistry
EARTH 331: Field Problems in Sedimentary Geology
EARTH 440: Paleoceanography

Selected Publications

Kitch G.D., Jacobson A.D., Hurtgen M.T., Sageman B.B., Harper D.T., Zachos J.C. (2021) Calcium isotope composition of Morozovella over the Late Paleocene-Early Eocene. Geology, v. 49, p. 723-727.

Wang J.W., Jacobson A.D., Sageman B.B., Hurtgen M.T. (2021) Stable Ca and Sr isotopes support volcanically-triggered biocalcification crisis during Oceanic Anoxic Event 1a.  Geology, v. 49, p. 515-519.  DOI:  10.1130/G47945.1.

Joo Y.J., Sageman B.B., Hurtgen M.T. (2020) Data-model comparison reveals key environmental changes leading to Cenomanian-Turonian Oceanic Anoxic Event 2.  Earth-Science Reviews, v. 203, p. 1-15.

Linzmeier B.J., Jacobson A.D., Sageman B.B., Hurtgen M.T., Ankney M.E., Petersen S.V., Tobin T.S., Kitch G.D., Wang J (2020) Calcium isotope evidence for environmental variability before and across the Cretaceous-Paleogene mass extinction. Geology, v. 48, p. 34-38.

Wang J.W., Jacobson A.D., Zhang H., Ramezani J., Sageman B.B., Hurtgen M.T., Bowring S.A., Shen, S. (2019) Coupled d^44/40Ca, ⁸⁷Sr/⁸⁶Sr, and d^88/86Sr geochemistry across the end-Permian mass extinction event. Geochimica et Cosmochimica Acta, v. 261, p. 143-165.

Kristall B., Jacobson A.D., Sageman B.B., Hurtgen M.T. (2018) Coupled strontium-sulfur cycle modeling and the Early Cretaceous sulfur isotope record.  Palaeogeography, Palaeoclimatology, Palaeoecology, v. 496, p. 305-322.

Mills J.V., *Gomes M.L., *Kristall, B., Sageman B.B., Jacobson A.D., Hurtgen M.T. (2017) Massive volcanism, evaporite deposition, and the chemical evolution of the Early Cretaceous ocean.  Geology, v. 45, p. 475-478.  doi:10.1130/G38667.1

Kristall B., Jacobson A.D., Hurtgen M.T. (2017) Modeling the seawater radiogenic strontium isotope record:  A case study of the Late Jurassic – Early Cretaceous.  Palaeogeography, Palaeoclimatology, Palaeoecology, v. 472, p. 163-176.

Holmden C., Jacobson A.D., Sageman B.B., and Hurtgen M.T. (2016) Response of the Cr isotope proxy to Cretaceous Ocean Anoxic Event 2 in a pelagic carbonate succession from the Western Interior Seaway.  Geochimica et Cosmochimica Acta, v. 186, p. 277-295.

Gomes M.L., Hurtgen M.T., and Sageman B.B. (2016) Biogeochemical sulfur cycling during Cretaceous Ocean Anoxic Events: A comparison of OAE1a and OAE2.  Paleoceanography, v. 31, p. 233-251, doi:10.1002/2015PA002869.

Sim M.S., Ono S., Hurtgen M.T. (2015) Sulfur isotope evidence for low and fluctuating sulfate levels in the Late Devonian ocean and the potential link with the mass extinction event. Earth and Planetary Science Letters, v. 419, p. 52-62.

Gomes M.L., Hurtgen M.T. (2015) Sulfur isotope fractionation in modern euxinic systems: Implications for paleoenvironmental reconstructions of paired sulfate-sulfide isotope records.  Geochimica et Cosmochimica Acta, v. 157, p. 39-55.