Alum Alex Rytel begins work at the Capitol
Achieving his goal of working as a science policy advisor to Congress, alumnus Alex Rytel (pictured above) recently began a full-time position as a Research Assistant & Staff Assistant for Congresswoman Marcy Kaptur at the US House of Representatives.
Saltzman co-authors a new Nature Geoscience article on the Permian-Triassic mass extinction
Saltzman and former PhD student Kate Tierney were co-authors on a new paper published in Nature Geoscience that pairs lithium and strontium isotopes across the Permian Triassic mass extinction interval. The paper explains why it took 5 million years after the end of Siberian Traps volcanism for life to recover. The study was led by Dr. Xiao-Ming Liu and her PhD student Cheng Cao at UNC-Chapel Hill.
Download the full article here!
–Matt Saltzman
Graduate student Chris Conwell publishes paper titled "Nd isotopic evidence for enhanced mafic weathering leading to Ordovician cooling"
Modern studies of river chemistry, continental rock weathering, and numerical modeling support the hypothesis that chemical weathering of mafic rocks constitutes a major sink for atmospheric CO2 which could, on geologic timescales, be a primary driver of global cooling and glaciations. This work investigates the link between mountain building, continental weathering, and global cooling during the Ordovician (487–443 Ma) greenhouse–icehouse transition which culminated in the first glaciation and mass extinction of the Phanerozoic, marking a prominent and irreversible fork in the evolution of life. We investigated chemical proxy signals for continental weathering source lithology (87Sr/86Sr and εNd(t)) and compared these to published paleotemperature proxy measurements (conodont δ18O) all from a Middle–Late Ordovician (~470–450 Ma) platform carbonate deposit in central Nevada. Our results show a dramatic shift in weathering proxy signals at ~463 Ma to values indicating an increased proportion of mafic rock weathering, supporting an enhancement of the mafic weathering CO2 sink driven by uplift of oceanic crust during the Taconic Orogeny. This observation is validated by a pronounced shift in the δ18O paleotemperature record to cooler paleotemperature values roughly coeval with shifts in weathering proxy signals. We also observed in a numerical modeling exercise that enhanced mafic weathering could have produced the cooling observed in the δ18O record within carbon and 87Sr/86Sr mass balance constraints. This is one of the first times we’ve been able to observe a climate response to enhanced mafic weathering in the geologic record, and I hope this work will lead to more chemostratigraphic investigations of weathering–climate link during dynamic periods of Earth’s climate history.
To read Chris's article, download the full text here!
–Chris Conwell
Audrey Saywer's lab travels to Bloomington
Professor Audrey Sawyer’s research lab traveled to Bloomington, Indiana this month to share their research with INTERA’s Midwest Team. We enjoyed learning about INTERA’s career opportunities and catching a glimpse of Indiana University. We thank Jack Wittman for the invitation
–Audrey Sawyer