Chromatography and Paleoceanography
PI: Brian Haley
Plasma spectrometry has opened the door to past climate by making it possible to examine the elemental composition of microfossils in unprecedented detail. One of our fundamental goals at the Keck Lab is to move past the conventional aspects of this powerful technology by developing new methodologies for pre-treating samples before introduction into the plasma. Pretreatment results in cleaner signals with better precision and accuracy, and oftentimes more scientific information per sample. We support conventional chromatography front-ends as well as an automated leaching module that we use to resolve the complex chemistry of fossils – most notably shells of foraminiferal from sediment cores. The Keck lab works closely with Dionex Corp. and Thermo Scientific to continuously upgrade and improve these capabilities.
PI: Brian Haley
Most elements in nature have two or more isotopes, which can vary in their proportions due to natural (and artificial) processes. While similar to the “light” elements carbon and oxygen analyzed in the stable isotope lab, the isotopes of “heavy” elements measured in the Keck Collaboratory are generally those of metals and metalloids. Strontium (Sr), neodymium (Nd) and lead (Pb) are three of the more common isotope systems we analyze routinely. However, other isotope systems, from the Uranium-series isotopes of the heaviest atomic masses to the lithium isotopes of the lightest atomic masses, are possible to analyze using the Nu Plasma Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS) at OSU. Analysis of these isotopic systems is used to reveal the processes that shape this planet, from the mantle to the oceans to climate change.
Fish Mixing & Migration
PI: Jessica Miller
Efforts to manage and protect fisheries resources are often hampered by inadequate information. Hard structures – otoliths, bones, and scales – provide a wealth of information on the age, growth, origin, and movement and migration patterns of fishes. In the Keck Lab, the capacity to collect high resolution elemental and isotopic data on bony structures allows us to address important management and conservation questions regarding larval dispersal and movement patterns in marine fishes and natal origins and migratory behavior in anadromous fishes, such as Chinook salmon. We can also probe the past by using modern analytical approaches on archaeological bone and otolith samples to provide information on extirpated populations that may aid the maintenance and restoration of extant populations.
PI: Adam Kent
Laser ablation ICP-MS analysis uses a focused laser to vaporize or “ablate” solid materials. The ablated material is then transferred to a plasma mass spectrometer for analysis. As the laser can be very finely focused the technique allows us to measure the chemical and isotopic composition of very small (0.01 – 0.1 mm) domains within glasses, minerals, speleothems, otoliths and other solid samples. In the Keck Lab, some of the scientific questions that we are addressing using laser ablation are: the origin and evolution of magmas within the Earth’s crust and mantle and the processes that lead to the eruption of volcanoes; the current and past migration histories of salmon and steelhead; past climate and ocean conditions and climate change; and the processes that lead to formation of economic mineral resources.
PI: Marta Torres
Fluid flow through the oceanic lithosphere exerts fundamental controls in a variety of processes in the solid Earth, oceans and the biosphere. Fluids and associated diagenetic reactions affect hydrological parameters (e.g. permeability, pore pressure), which are thought to play a key role in earthquake nucleation in subduction zones. Deep-sourced fluids bring chemicals and energy from the root of accretionary prism to seafloor, and thus affect the deep biosphere. Carbon cycling and hydrocarbon transport play important roles in the accumulation of methane and gas hydrates; which in turn may impact climate, slope stability, and modulate fluid discharge at the seafloor. The distribution of lithium, boron, chloride and strontium, and their isotopes in sediment and pore waters allow us to trace flow into and out of the volcanic crust, from ridges to the trench, within subduction zones and along continental margins. We take advantage of the tremendous capabilities of the Keck Collaboratory to measure concentrations of trace elements in small volume of fluids, as well as to characterize their isotopic composition in a variety of subduction zones worldwide. These data have been key in identifying fluid sources, fluid-rock reactions, pathways of fluid migration and the plumbing of the different systems, which form our current understanding of the roles played by fluids in the biogeochemical and mechanical properties of deep-sea sediments.