News

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SCIPP Lab reopens following 2+ month hiatus

Today we gained access to our research lab for the first time since we shutdown in March.

We are very glad to be selected as one of the buildings for the “pilot phase” of reopening at U of M. The group, department, and university have done a great job making the working environment safe through PPE, cleaning and air circulation procedures, limiting personnel, and maintaining social distancing. Lots of safety plans submitted!

Only Ashling, our lab manager, is allowed in at the moment and she will begin working to turn on our machines and get them back to operational. We are crossing our fingers for a smooth reopening, with everything working well.

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Serena and Steve graduate!

Congratulations to our SCIPP group graduates! Senior thesis student Steve Wedel finished his undergraduate degree in Geology and Serena Scholz completed her master’s degree with a very impressive master’s thesis (one paper published, another nearly submitted).

Although the in-person graduation ceremonies were canceled due to COVID-19, we are still so proud of you guys! Sad to see you go, but excited to see the next steps in your bright futures!

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New Paper Update: Tropical Seasonality in the Miocene

Serena’s first paper was just published in Geology! She measured the oxygen isotopic composition of modern and fossil gastropod shells of the genus Turritella at high (subannual) resolution. In tropical settings, temperature doesn’t vary too much throughout the year, so the large seasonal variations in d18Ocarbonate were therefore attributable to changes in d18Oseawater, which she linked to on-shore precipitation. This indicated that there was a high seasonality of precipitation at the sample site (Guajira Peninsula, Colombia), which is today an extremely arid environment. She suggested that the Intertropical Convergence Zone (ICTZ), a band of high precipiation, could have extended to a more northerly position during the warm Miocene and been the source of this increased precipitation seasonality.

Congrats Serena on your first paper!

 

Link to Paper

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New Paper Update: Synthesis of Paleosol Clumped Isotope Data

Julia Kelson (collaborator and now postdoc in the SCIPP group) published a compilation study of all published paleosol clumped isotope data to investigate whether any patterns could emerge regarding seasonal timing of formation or temperature biases. She updated older data using the Brand/IUPAC parameters and culled out early data that didn’t meet current data collection standards.

She found that paleosol carbonates tend to show a warm season bias, and calculated d18Owater values are related to d18Oprecipiation values from the season of carbonate formation.

 

 

Link to Paper

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SCIPP Lab closes for COVID-19

Today we shut down our two mass spectrometers and turned off and unplugged all our smaller equipment. All U of M research labs are shutting down as the university and state shift to a new “work from home” normal to combat this growing health crisis. Although as lab scientists we are always hoping to be gathering new data, this comes at an okay time for our group, following a big data collection push in January and February. Everyone has data to process, analyze, interpret, and write up. We hope to be back in the lab, collecting new data, as soon as is safe. For now, see everyone on video!

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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

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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.

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New Paper Update: Community-Wide Clumped Calibration Efforts

Sierra wrapped up a community-wide effort to reprocess and update clumped isotope calibration data from 11 different laboratories, including over 1200 individual replicates, to bring it into the same framework. This involved updating the fundamental parameters R13_VPDB, R17_VSMOW, R18_VSMOW, and λ used to calculate raw D47, using a consistent and updated set of theoretical equilibrium values (D47_TE) to tie things into the absolute reference frame, and applying a single set of acid fractionation factors (D*90-25) across all studies. We found that agreement is quite good between labs, once all the data processing is done uniformly and the “two-slope” or “multi-slope” problem that plagued the clumped community in the early days has all but disappeared in more recent studies.

Link to paper here

 

As part of this effort, we also developed a data template and began a relationship with the EarthChem database to house future clumped isotope datasets in a long-term storage location. For more information on that, see this page.