David K. Watkins

Micropaleontology & Marine Geology

Professor of Earth & Atmospheric Sciences
214 Bessey Hall
University of Nebraska-Lincoln
Lincoln NE 68588-0340 USA
(phone) 1-402-472-2177
(fax) 1-402-472-4917
email: dwatkins@unl.edu

Cretarhabdus conicus from Albian, western North Atlantic (SEM).

My research is based on calcareous nannofossils, the smallest of all skeletal fossils routinely preserved in marine sediments. They are the main component of chalk (above). The rapid evolution of this group and their global distributions make them ideal biostratigraphic indicators for the Late Triassic through Recent. My students and I are currently pursuing projects to examine the variations in the biostratigraphy of both Cretaceous and Cenozoic nannofossils. Both probabilistic and deterministic methods of quantitative biostratigraphy are being used to define the most reliable bioevents. We are interested specifically in biostratigraphic variations that are related to differences in paleobiogeographic realm (both latitudinal and inter-oceanic) and to position of depositional systems relative to proximity to shore. We are currently working with records from the Cenozoic of Antarctica and the Southern Ocean, the Paleogene of the temperate regions, and the Cretaceous of North America and the world ocean.

Major perturbations in oceanic surface-water characteristics, such as OAEs and thermal excursions, can drive the rapid evolution of the plankton. We are looking at the detailed evolution of several groups associated with these major oceanic perturbations in an effort to understand and document the mechanics of evolutionary change from a geological perspective. This includes work within a single species (e.g., Axopodorhabdus biramiculatus) and within major clades (e.g., Eiffellithus). By using astronomically tuned records, we are able to define the precise timing of speciation events and track the rise and fall of species during intervals of rapid global change.

Bryan Hermosillo (M.S. student)
Bryan is examining the calcareous nannofossil biostratigraphy and paleoecology of the Coniacian stage from various locations.

Andy studied the quantitative biostratigraphy of the nannofossils from the Paleocene/Eocene transition to the middle Eocene of the Gulf of Mexico and western North Atlantic. In addition, he used quantitative methods to study the paleoecology of these Paleogene assemblages. He also used quantitative biostratigraphic methods to propose a new zonation for the Miocene of the Gulf of Mexico (published in SEPM Special Publication No. 93). He currently is employed at Statoil as a Nannofossil Biostratigrapher.

Jamie used nannofossils to construct a biostratigraphic and paleoecologic framework for the Eocene deep water deposits off the northwestern Australian margin, in cooperation with Exxonmobil. Her research results on the Sphenolithus lineage are published in the Journal of Nannoplankton Research. Her results on biostratigraphy, biogeochronology, and paleocommunity structure are published in Stratigraphy. She is currently employed at ExxonMobil as a Nannofossil Micropaleontologist.

John used carbonate content and nannofossil assemblage changes to characterize the invasion of oceanic surface waters into the Western Interior Seaway during the early to late Maastrichtian using outcrop samples from the Mobridge Member (Pierre Shale). After graduation he joined Paleodata, Inc. as a Nannofossil Micropaleontologist.

Jamie analyzed the evolution of the genus Eiffellithus, an important biostratigraphic and paleoecologic indicator in the Upper Cretaceous. She differentiated several new taxa and documented a pattern of iterative evolution. Her research results are published in Cretaceous Research. She presented the results of her research at the 2008 AAPG Convention, where she was awarded Honorable Mention in the SEPM Excellence of Poster Presentation. After graduation she entered the Ph.D. program at the University of Nebraska (see above).

Stacie used calcareous nannofossils to construct a high-resolution biostratigraphy for the Coniacian/Santonian stage boundary in the Western Interior Basin. Her research results are published in Cretaceous Research. After graduation she entered the Ph.D. program at Florida State University.

Ryan used nannofossils as evidence for an impact-induced tsunami in the Late Cretaceous Western Interior Seaway from the Crow Creek Member (Pierre Shale). His work is published in Geology. After graduation he joined Paleodata, Inc. as a Nannofossil Micropaleontologist.