Paleoclimate and Paleoenvironmental Change
The UC Davis Earth and Planetary Sciences department has outstanding facilities to support work done in sedimentology, stratigraphy, paleoceanography, paleomagetism, and low temperature geochemistry. In-house light stable isotope ratio mass spectrometers include Fisons Optima and Finnigan MAT 251 mass spectrometers with automated capabilities for analyzing carbon and oxygen isotope ratios on very small carbonate samples, carbon and nitrogen isotope ratios on organic matter, and oxygen and hydrogen isotope ratios on waters. A third continuous flow stable isotope mass spectrometer is available for sulfur isotope analyses; and a fourth IsoPrime IRMS can analyze carbon and oxygen isotopes in carbonates in dual inlet mode as well as analyzing microliter-sized water samples and organic matter (for H and O isotopes) and oyxgen isotopes on minerals such as phosphate, nitrate and sulfate (O isotopes) in continuous flow mode. Off line isotopic separation facilities include vacuum lines for carbonates, organic carbon, total CO2 in water, hydrogen and oxygen in silicates, and sulfur in sulfides and sulfates.
A fully equipped paleomagnetics laboratory, including two SQUID magnetometers and various equipment to characterize magnetic properties, is also available in the Earth and Planetary Sciences department. A scanning electron microscope with EDS X-ray and image processing capabilities is available, as well as a fully automated CAMECA electron microprobe; and the Davis campus has recently installed a state of the art multi-collector ICP-MS (Nu Plasma HR) and two quadrupole ICP-MS (Agilent Technologies 7500a and 7500c) and a laser ablation system (New Wave Research UP-213) for trace element and radiogenic isotope measurements. Additional research facilities include a cathodoluminescence microscope, an epi-fluorescence reflected light microscope, various petrographic (including reflected light) microscopes, a fluid inclusion heating and freezing stage, and X-ray fluorescence and diffraction spectrometers. The Earth and Planetary Sciences department also has a well supported, in-house computing network and a microcomputer laboratory for research and teaching.
Faculty research interests include:
- Environmental Geology (Verosub, Zierenberg): Acid Mine Drainage; Biological and Geological Sulfur Cycles; Environmental Magnetism
- Fluvial Geomorphology (Mount): Riverine Responses to Land Use Practices; Analysis of Sediment Transport; Floods
- Ocean Chemistry: Archean to Modern (Hill, Montañez, Spero, Sumner, Zierenberg): Environmental Control of Stable Isotope Variation in Foraminifera and Other Fossil Invertebrate Groups; Carbonate Precipitation Processes in Ancient Oceans; Hydrothermal Systems
- Paleoclimatology (Hill, Montañez, Spero, Verosub): Quaternary paleoclimate records from the magnetic properties of sediments and soils; Paleoenvironmental reconstructions from fossil foraminifera; Permian paleosols as proxies for climate change
- Paleomagnetic Studies (Verosub): Correlation of sedimentary sequences using paleointensity; Post-depositional alteration of sediments; Applications of paleomagnetism to geological problems
- Stratigraphy (Montañez, Mount, Sumner): Stratigraphy and sedimentology of the Neoproterozoic-Cambrian Transition; Cambrian Carbonate and Mixed Siliciclastic-Carbonate Sequences; Distribution and Depositional Environments of Marine Calcite and Aragonite Precipitation; Late Devonian Chemical and Biological Changes in Reef Environments
Graham Fogg. Groundwater contaminant transport; groundwater basin characterization and management; geologic/geostatistical characterization of subsurface heterogeneity for improved pollutant transport modeling; numerical modeling of groundwater flow and contaminant transport; role of molecular diffusion in contaminant transport and remediation; long-term sustainability of regional groundwater quality; vulnerability of aquifers to non-point-source groundwater contaminants.
Tessa Hill. Research areas include marine micropaleontology, geological oceanography, and paleoceanography utilizing geochemistry of marine sediment and coral records. Tessa is also involved in interdisciplinary research to investigate the impacts of ocean acidification on coastal California environments. Research in her laboratory includes
- Culturing of key species in the laboratory under controlled environmental conditions
- Monitoring modern pH variability on the Northern California coast using pH sensors and oceanographic transects
- Reconstructing climate variability utilizing geochemical proxies in foraminifera, corals, and other carbonates
- Investigating coastal environments to understand potential for carbon storage
Isabel Montañez. Research interests are in the sedimentary record of coupled physical and chemical variation in paleo-oceans, global biogeochemical cycling in marine and terrestrial records, and carbonate fluid-rock interaction in sedimentary basins using stratigraphy, petrography and geochemistry, including stable and radiogenic isotopes and trace elements. Research in the laboratory broadly focuses on development of quantitative paleoclimate proxies, and their application to intervals of time characterized by major and/or abrupt climate change including past periods of icehouse-to-greenhouse transitions through to the last deglaciation.
Sujoy Mukhopadhyay. Early terrestrial atmospheres, magma oceans and the early volatile history of Earth, chemical evolution of the mantle-crust-atmosphere system, application of surface exposure dating to understanding land surface evolution, novel techniques for reconstructing mineral dust emission from continents and climatic effects of mineral dust, sediment mass accumulation rates from extraterrestrial helium-3.
David Osleger. Stratigraphy and sedimentology applied to paleoenvironments, paleoceanography and paleolimnology. Research interests include orbital stratigraphy, sea-level history, carbonate platform evolution, petrophysical heterogeneity of hydrocarbon reservoirs, lacustrine sedimentation and paleoclimatology. Current projects include the relationship between Sr isotopic content of the oceans and sea-level chronology, the global climatic significance of episodes of oceanic anoxia recorded in Cretaceous carbonates of northeastern Mexico, and the paleoclimate history of the High Sierra as deduced from Lake Tahoe sediment cores.
Nicholas Pinter. My research focuses on earth-surface processes (geomorphology) applied to a broad range of problems. Much recent work involves rivers, fluvial geomorphology, flood hydrology, floodplains, and watersheds. My research group applies fluvial geomorphology, hydrologic and statistical tools, hydraulic modeling, and other approaches to assess river dynamics and flood hazards. Although much current research focuses on rivers, I continue to work on a broad range of processes that shape the earth surface and operate, in particular, over anthropogenic time scales (yes, the "Anthropocene"). One pressing human application is for managing risk from natural hazards, and my group has worked extensively on quantifying those risks, guiding mitigation and other solutions, and providing a scientific basis for sound natural-hazards public policy.
Howard Spero. Stable isotope and trace metal geochemistry, paleoclimatology, marine micropaleontology, and paleoceanography. Research focuses on the biological and environmental parameters that affect the stable isotope and trace metal geochemistry of the shells of recent and fossil organisms; paleoclimatology, marine micropaleontology, and paleoceanography. An ongoing multi-year field research program involving undergraduate and graduate students has been studying living planktonic foraminifera in the Southern California Borderland and the Caribbean. The results of this study are being used to interpret fossil foraminifera stable isotope data from Indian and Atlantic Ocean deep sea cores in order to reconstruct paleoenvironmental sea surface temperatures, nutrient levels and CO2 concentrations during the Pleistocene.
Dawn Sumner. My research uses stratigraphic, sedimentological, and petrographic studies of carbonate sequences to reconstruct ancient environments and ocean chemistry, the Mars Science Laboratory to develop environmental and stratigraphic models for strata in Gale Crater, Mars, and diverse techniques to understand the effects of recent climate change on photosynthetic microbial communities growing in ice-covered Antarctic lakes.
Please see http://mygeologypage.ucdavis.edu/sumner for ongoing projects.
Kenneth Verosub. Environmental magnetism, quaternary paleoclimate records, correlation of sedimentary sequences using paleointensity, post-depositional alteration of sediments, applications of paleomagnetism to geological problems, and science education. Recently he has become more generally interested in the influence of geologic processes on the development of societies, civilizations and cultures. In addition to on-going paleomagnetic and environmental magnetic studies, he is working on volcanic eruptions that have caused global cooling, seismic risk and subsidence problems in the Sacramento-San Joaquin Delta, the identification of deep groundwater aquifers and the determination of river flows directly from geospatial imagery.
Robert Zierenberg. Aqueous geochemistry, stable isotope geochemistry, and economic geology. Research has focused on water/rock interaction in active and ancient hydrothermal systems, including the "black smokers" on the mid-ocean ridges. Other interests include the environmental effects of mining, particularly the generation of acid mine drainage, mercury contamination in Clear Lake related to the abandoned Sulphur Bank Hg mine, the geochemical and biological cycling of sulfur, and sulfur isotope geochemistry.
Scientists & Academic Federation Members
Irina Delusina. Assistant Project Scientist. High-resolution records of climate change from ocean and lake environments as determined by palynological analyses. Reconstruction of vegetational history of late-glacial environment and its paleoclimatic implications. Evidence for the response of plant communities to climatic oscillations and analysis of environmental parameters responsible for vegetational alteration. Current research projects encompass California and the Caribbean region, including the palynological study of vegetation evolution and optimal conditions for the formation of peat in the Sacramento-San Joaquin Delta and marine sediments of the Cariaco Basin of Caribbean Sea as a source of information for paleoclimate reconstruction in a Neotropical region during late-glacial/Holocene transition.
Ann Russell. Associate Research Scientist. Paleoceanography and chemical oceanography. Research focuses on development and application of geochemical tracers of changes in ocean chemistry, including metals and stable isotopes in foraminiferal shells, and redox-sensitive metals in bulk sediments. She uses these geochemical tracers to reconstruct changes in ocean temperature, carbon chemistry, and redox environment from deep-sea sediment cores.
Roy Shlemon. Applications of Quaternary geology, geomorphology and soil stratigraphy to engineering practice. Fault-activity assessments; natural and anthropic influences on slope stability; paleochannels and contaminant pathways.