New Paper Update: Tropically Hot Cenomanian temperatures in the Western Interior Seaway

The latest SCIPP-Lab paper comes from former SCIPP-lab postdoc Dr. Matt Jones (now at the Smithsonian Institute), publishing the work he did while at UM. Dr. Jones looked at fossil oysters from the Cretaceous Western Interior Seaway and used clumped isotope to reconstruct seaway temperatures during the time they lived.

We found that temperatures during the Cretaceous Thermal Maximum (Cenomanian-Turonian period, ~95 Million years ago) reached upper 20’s to lower 30’s Celsius in what is now modern day Utah and Wyoming. This is very hot! These water temperatures, which occurred in the mid-latitudes during the Cretaceous, are today only found in the warmest areas of the ocean like the Western Pacific Warm Pool. It makes you wonder how hot the tropics were if the mid-latitudes were >30C!! But that’s for another day…

Some Cenomanian-Turonian oyster fossils used in this study

Shell cross section, showing growth banding (and some calcite veins).

LINK TO PAPER: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G49998.1/613546/A-tropically-hot-mid-Cretaceous-North-American

LINK TO UM PRESS RELEASE: https://news.umich.edu/bali-like-temperatures-in-wyoming-fossils-reveal-tropically-hot-north-america-95-million-years-ago/

LINKS TO OTHER PRESS: Futurity article, Science Daily article,

Heidi submits her thesis and manuscript!

Despite setbacks due to COVID, our very own Heidi O’Hora submitted her masters thesis this week to graduate end-of-summer, and then turned around and submitted her manuscript to a top-tier journal for peer review and (hopefully) eventual publication in the scientific literature. Congratulations Heidi, you did it! We are so proud of the progress you’ve made over the past 2 years, especially considering it was such an unusual time.

Heidi’s thesis project involved reconstructing Late Cretaceous ocean temperatures in the modern-day region of Maastricht, the Netherlands. Her samples come from the type section of the Maastrichtian (ENCI quarry) among other locations. She found that temperatures in that area were much warmer than they are today (as expected for the greenhouse world of the Cretaceous) and that interactions between different water masses had a strong control on local ocean temperature and salinity.

Stay tuned for publication announcement later on!

New Paper Update: Mercury Signal of Deccan Traps Volcanism

Kyle’s last thesis chapter was just published in Nature Communications! He analyzed the total mercury content (T[Hg]) in fossil shells from around the world, dating to the period leading up to the Cretaceous-Paleogene boundary. He found elevated Hg levels in samples dating from within the time period when the Deccan Traps were erupting, with lower “baseline” levels prior to that. This new method of measuring Hg in shell material (as opposed to sediment) eliminates some of the issues of [Hg] dependence on sediment organic carbon content. He was able to quantify that the mercury contamination during the time of Deccan volcanism was significantly higher than modern sites considered to be highly contaminated!

Link to Paper

New Paper Update: Calcium Isotopes and Ocean Acidification across the K-Pg boundary

Our collaborator Benjamin Linzmeier just published a nice paper in Geology looking at calcium isotopes in fossil bivalves spanning the K-Pg boundary. The calcium isotopic composition (44Ca/40Ca) of carbonate is a proxy for carbonate saturation state and can indirectly indicate something about ocean acidification state. Ben analyzed shells from Seymour Island that were previously analyzed for their clumped isotopic composition in the SCIPP lab (Petersen et al., 2016; Nature Communications). We found that the ocean’s carbonate saturation state was highly variable leading into the KPg boundary, which we attribute to CO2 injection into the atmosphere from the massive Deccan Traps volcanic province.

New Paper Update: Cretaceous Temps in the Gulf Coast

Kyle Meyer’s thesis chapter was just published in Cretaceous Research. Link to the paper here. Very exciting to finally have these results out. He found clumped isotope temperatures similar to today for the Late Cretaceous (Campanian-Maastrictian) in multiple sites along the Gulf Coast and one site in New Jersey. He also compared multiple taxa from the same site and found no significant vital effects.

New Paper Update: High-Resolution climate records from Cretaceous oysters

Our collaborator Niels de Winter just had his (our) paper come out in Climate of the Past. Link to Paper here.

Niels used many proxy methods to assess the preservation of climate information in Cretaceous oysters from the Nequen Basin (Argentina). He found that the umbo/hinge region where calcite is densest is the best place to sample to reveal climate information. Porous zones of “honeycomb” carbonate had been replaced with secondary calcite with divergent isotopic compositions.