We are very excited to welcome our newest group member, Jade Zhang (incoming PhD student) to Ann Arbor, finally. In addition to being accepted into our program, Jade was also awarded the Rackham Merit Fellowship. Way to go, Jade! We can’t wait to see you take off here.
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.
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.
Petersen group members came up big at the annual Earth and Environmental Sciences Department Dorr Awards Dinner. Kyle Meyer received the Outstanding Graduate Student Instructor Award and Serena Scholz won the Department Award for Academic Excellence. Sierra got to present the award to Serena. We were all very proud!!
We propose a new mechanism to explain Heinrich Events involving subsurface warming eating away at the foot of an ice stream in the Hudson Strait, causing dramatic retreat. The new element we incorporate is the response of the solid earth to the repeated regrowth and removal of the ice stream. The rebound of the bedrock modulates the timescales of regrowth and can help explain why Heinrich Events only occur during certain Dansgaard-Oeschger cycles.
We found that, in Bermuda, interglacial climate during MIS 5e was slightly cooler than modern. This is in line with CLIMAP reconstructions of the North Atlantic region. At a second MIS 5e outcrop a few km away from the first, we also found evidence for meltwater (10C cooler temps, 2 permil lower d18Owater), which was very surprising, given the mid-ocean location of Bermuda. Based on the age, we attribute this meltwater to melting Greenland.
Surprising and exciting results!!