2017-2018 Schlanger Fellow – Heather Jones

Heather Jones

Pennsylvania State University


Survivorship and recovery of calcareous nannoplankton following the K/Pg mass extinction at “ground zero”



Nannoplankton suffered a severe mass extinction at the K/Pg boundary. Although the subsequent recovery was hemispherically asynchronous, it is uncertain how it was impacted by distance to the crater. A new stratigraphically complete and expanded K/Pg section from the Chicxulub Crater presents a unique opportunity to examine survivorship and recovery patterns at “ground zero”. By comparing data from the impact site to a little-studied South Atlantic core, the proposed study will determine how severely nannoplankton recovery was delayed, where new species originated and dispersed to, and, possibly, where Cretaceous taxa survived.




My interest in microfossils began when I was an undergraduate at the University of Southampton (UK), where I learned how important they are to biostratigraphic and paleoenvironmental studies. To explore this application further, I worked with Dr. Samantha Gibbs for my Master’s thesis to investigate whether the cell architecture of two coccolithophore species changed during the Paleocene-Eocene Thermal Maximum (PETM). During this research project I became “addicted” to hunting for coccospheres. This motivated me to pursue a PhD so that I can better understand how these critical organisms respond to periods of environmental change. My current research focuses on calcareous nannoplankton recovery following the K/Pg mass extinction at El Kef, Tunisia. Nannoplankton recovery assemblages at this site are characterized by successions of “bloom” species, but we are uncertain about which environmental and/or ecological variables drove changes in dominant taxa. To answer this question, I am comparing my high-resolution nannofossil assemblage counts to other faunal data (i.e. foraminifera and dinoflagellate abundance counts) and geochemical proxies. I am excited about the opportunity to study nannoplankton recovery at “ground zero” during my Schlanger fellowship, and plan to compare assemblage counts from Chicxulub to those at El Kef. This will allow me to determine how environmental and ecological controls on nannoplankton recovery changed as a function of distance from the impact crater.