This award provides funding over 24 months to acquire an excimer laser and quadrupole inductively coupled plasma mass spectrometer (ICP-MS) for high-resolution paleoclimatological elemental and isotopic measurements. The requested configuration will allow analyzing a broad suite of elements and isotopes. Various geological materials can be analyzed and the instrument offers a rapid (<0.5 sec/analysis) sample throughput. The laser will offer ultra-high resolution (micron to nanometer spatial scale), and the system will have minimal inter-sample memory problems. Accuracy and precision will be comparable to wet plasma ICP-MS systems. The system will especially useful for measuring Metal/Ca (e.g. Mg/Ca, Ba/Ca, B/Ca etc.) and stable isotopes (carbon and oxygen). Research will focus primarily on paleoclimatic and paleoceanographic questions but the instrumentation will be applicable to many geoscientific-related themes. The new instrument will be a valuable training tool for graduate students, post-docs and exceptional undergraduates. The instrument will be used for teaching by the PI and Co-PIs in graduate and undergraduate geochemistry courses and undergraduate research projects and senior theses. This state-of-the-art instrumentation, unique in the US will allow the PIs, students and postdocs to remain at the forefront of new research areas and techniques. The instrument will be moved into a recently-renovated laboratory space. The PIs will collectively be responsible for operation and maintenance. Grant income and recharge funds will be used to maintain the instrument and support a technician. The administration will fund major repairs.
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The primary objective of this proposal was to obtain funds to purchase a quadrupole inductively coupled plasma mass spectrometer (ICP-MS) and an Analyte.193 Ultra-short pulse Excimer Laser Ablation (LA) System with dual volume cell, in order to apply recent advancements in this coupled emerging technology to fundamental paleoclimatic and paleoceanographic research questions. We have now installed, calibrated and tested our new ICP-MS/LA system to analyze the elemental composition of fossil and microfossil samples such as foraminifera shells. Elemental ratios such as Mg/Ca and Ba/Ca provide fundamental information about environmental conditions, such as ocean temperatures and salinities, which existed during the life of these organisms. As such, we can reconstruct oceanic conditions during periods of abrupt climate change in Earth history with considerable accuracy and precision. A fundamental application of our new ICP-MS/LA system will be to quantify elemental ratio heterogeneity within fossil shells to sort out fundamental biological and environmental effects and mechanisms involved in the incorporation of these geochemical signals into shell calcite. In effect, this instrument will be used to ground-truth and calibrate the fundamental geochemical tools that are used to reconstruct past climate and ocean change. During the second year of this award, we completed two projects that are ready for submission to scientific journals. Study #1 focuses on optimizing the ICP-MS/LA for application to foraminifera shells. Laboratories around the world are beginning to produce data from systems similar to this one with mixed analytical results. The study we have just completed will establish initial operating conditions to produce accurate, high resolution data that can be intercompared among different laboratories. Study #2 explores different cleaning protocols for fossil foraminifera in order to quantify the shell material that is lost during cleaning. LA-ICP-MS measurements on the spherical chamber of the planktonic foraminifera, Orbulina universa, has allowed us to demonstrate the effects of such protocols and to establish the advantages of sonication in methanol over oxidative and reductive cleaning techniques. Although the primary research focus of our new ICP-MS/LA system will be in the general areas of paleoceanography and paleoclimatology, this instrument will also be available for research in an array of Geoscience fields. In this regard, our new system will serve a central role as a training instrument for graduate students, post-docs and promising undergraduates in the Department of Geology as well as a teaching instrument for the PI’s and Co-PI’s hands-on graduate and undergraduate geochemistry courses. This system will also contribute to undergraduate research projects and senior thesis research. Finally, we are excited that our new ICP-MS/LA system will allow us to train our students on the newest and most advanced instrumentation available today. Given the current level of competition in obtaining jobs after finishing a degree, as well as the fierce competition in attracting the most promising new Ph.D. students to Graduate Programs, it is critical that the Department of Geology at UC Davis continue to provide access to state-of-the-art instrumentation so that our students can stay at the forefront of new research areas and techniques.
