David K. WatkinsMicropaleontology & Marine Geology Professor & Chair of Earth & Atmospheric Sciences
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| Research | Current Students | Recent Graduates | Recent Publications | Courses | Vita |
| Our lab was highlighted in the recent issue (see page 4) of the Newsletter |
| of the North American Micropaleontology Section (NAMS) of SEPM |
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, 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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Zachary Kita (Ph.D. student) Zachary is examining the geochrological sequence of calcareous nannofossil events in the Coniacian through lower Campanian of the Western Interior Basin of North America. |
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Bobbi Brace (Ph.D. student) |
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| Matt Corbett (Ph.D. 2013) | Matt examinied the nannofossil biostratigraphy of the Cenomanian-Turonian Eagle Ford Formation from outcrop exposures in western Texas and correlative units from the Western Interior Basin. He currently has four publications in review from his doctoral work. Matt will join BP as a nannofossil micropaleontogist in June. |
| Bobbi Brace (M.S. 2012) | Bobbi studied the nannofossil genus Biscutum during its mid- and Late Cretaceous diversification in the western central Atlantic, Gulf of Mexico, and the Western Interior Basin. Her thesis research paper is currently in review. She is currently pursuing a Ph.D. program at the University of Nebraska (see above). |
Johnathon Kell (M.S. 2012) |
Johnathon examined the relationship of orbitally-driven surface water variations and nannofossil paleocommunity structure in the middle Eocene from Leg 171. He also participated in the International Ocean Drilling Program (IODP) Leg 330 expedition to the Louisville Seamounts of the South Pacific. After graduation, John worked as a nannofossil paleontologist with Fugro-Robertson in northern Wales. He is currently employed at Paleodata, Inc. as a Nannofossil Micropaleontologist. |
Kristen Mitchell (M.S. 2012) |
Kristen examined the late Albian and Cenomanian biostratigraphic succession of the nannofossil genus Prediscosphaera. Kristen works as an exploration geologist with Chevron. |
Andy Bowman (Ph.D. 2011) |
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 Shamrock (Ph.D. 2010) |
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 Sarao (M.S. 2009) |
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 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). |
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 |
Ryan Weber (M.S. 2006) |
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. |
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. |
| 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. |
