David K. WatkinsMicropaleontology & Marine Geology Professor & Chair of Geosciences Department of Geosciences |
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| Research | Current Graduate Students | Recent Graduates | Recent Publications | Courses | Vita |
Research
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| Cenomanian chalk from Greenhorn Limestone of Kansas (SEM) with Axopodorhabdus biramiculatus. | Cretarhabdus conicus from Albian, western North Atlantic (SEM). |
Braarudosphaera stenorheta from Albian, North Atlantic (cross-polarized light microscope) |
| 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. | |
| Calcareous nannoplankton are controlled strongly by the nature of the surface water mass they inhabit. This relationship exerts a primary control on their distribution and especially their abundance in fossil assemblages. We are using statistical and numerical analysis to derive the relationships of nannofossil abundance to surface water fertility and paleotemperature as a way to examine paleoceanographic change. We are currently looking at these nannofossil assemblage dynamics to explore the nature of cyclic sedimentation in the Upper Cretaceous and Paleogene. Oceanic anoxic events (OAE) are of special interest in this regard, as the large-scale storage of organic carbon during these times, important in the generation of hydrocarbon source beds, was driven at least in part by major changes in surface-water fertility. | |
| 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 from the deep sea, 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. | |
| Visit the International Nannoplankton Association website for more about nannofossils. |  |
| Visit the UNL Paleontology website for more about our offerings. | |
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Andrew Bowman (Ph.D. student) Andy is working on the quantitative biostratigraphy of the nannofossils from the Paleocene/Eocene transition to the middle Eocene of the Gulf of Mexico and western North Atlantic. He currently is employed at Statoil. |
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Jamie Shamrock (Ph.D. student) Jamie is using nannofossils to construct a biostratigraphic framework for Middle Eocene deep water deposits in the Pyrenees, in cooperation with Exxonmobil. She is currently employed at ExxonMobil. |
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Matt Corbett (Ph.D. student) Matt is examining the nannofossil biostratigraphy of the Santonian-Campanian stage boundary from outcrop exposures in Kansas and the Gulf Coast. |
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Kristen Mitchell (M.S. student) |
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Johnathon Kell (M.S. student) Johnathon is starting his masters work this semester. He is interested in the use of calcareous nannofossils in biostratigraphic determination as related to petroleum exploration. |
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Brandi Harkins (M.S. student) Brandi is examining the nannofossil biostratigraphy of the lower Miocene of the Gulf of Mexico using well material generously provided by Shell Oil. She is currently finishing her degree after doing an internship at Shell. She presented the results of her research at the 2008 AAPG Convention, where she was awarded 2nd Place in the student poster competition. She is currently employed at BP. |
| Todd Boesiger (M.S. 2005) | Todd examined the calcareous nannoplankton response to regression of the Campanian Niobrara Sea. After graduation he joined BP America, Inc. as a Nannofossil Paleontologist. |
| Emily Browning (M.S. 2005) | Emily’s research demonstrated elevated primary productivity of calcareous nannoplankton associated with Ocean Anoxic Event 1b (Aptian-Albian) using core material from Ocean Drilling Program Leg 171b. Her research results are published in Paleoceanography. After graduation she entered the Ph.D. program at the University of Massachusetts-Amherst. |
| Amanda Minert (M.S. 2005) | Amanda documented the evolution of the late Albian through Cenomanian calcareous nannofossil Axopodorhabdus biramiculatus using material from Ocean Drilling Program Leg 171b and Deep Sea Drilling Project Leg 79. |
Ryan Weber |
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. |
| Stacie Blair (M.S. 2006) |
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 |
| Jamie Shamrock (M.S. 2008) | 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). |
| John Sarao (M.S. 2009) | John used carbonate content and nannofossil assemblage changess 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. |
| Quantitative Methods in Paleontology (3 cr.) – Numerical and statistical analysis of paleontological data including biometry, synecology, and quantitative biostratigraphy. |
| Mesozoic Calcareous Nannofossil Paleontology (4 cr) – Biostratigraphy, paleoecology, and paleobiogeography of Mesozoic calcareous nannofossils. |
| Cenozoic Calcareous Microfossil Paleontology (4 cr.) – Biostratigraphy, paleoecology, and paleobiogeography of Cenozoic calcareous nannofossils. |