Research

There are a number of research projects on a variety of topics that are working through the lab.  Here are some of the most recent.

Multi-Daly Analyses
The Nu Plasma 3D has the unique detector configuration that includes 6 high sensitivity Daly detectors and 16 standard Faraday detectors.  This enables simultaneous analysis of multiple low- abundance isotopes using the Daly’s in addition to multiple high-abundance isotopes using the Faradays. Pb solutions are being used to calibrate the Daly-Faraday gains to ensure measurement accuracy and reproducibility and to determine accurate deadtime corrections for each Daly to ensure consistent ratios independent of solution concentration. Eleven measurements of solutions of SRM981, alternating between three different concentrations (0.4 ppb, 0.2 ppb and 0.1 ppb) yielded Daly/Daly ratios with reproducibility of ~0.2% 2SD and Faraday/Daly ratios with reproducibility of ~0.15% 2SD. Lead solution multi-Daly work has characterized multi-Daly behaviour in preparation for U and Th isotope analyses for U-Th geochronology and ocean anoxia studies and is the first step in developing multi-Daly laser ablation techniques.

Li isotopes in pedogenic carbonates and clays (Evan Ramos, PhD candidate)

This research concerns the role of fluid-rock interactions in modulating biogeochemical cycles on Earth, notably the geologic carbon cycle. I primarily analyze the elemental and stable isotope geochemistry of fluvial sediments and river water to understand the environmental and geologic controls on silicate weathering over a range of time scales (modern to millions of years ago). I use the Isotope Clean Lab to prepare samples for Li isotope analysis: a stable isotope system that is becoming increasingly useful in assessing modes of silicate weathering in modern and ancient surface environments. I often pair Li isotope measurements of sediments and water with major and trace element analysis, which involves additional preparation and analysis in the Quadropole ICP-MS lab under the direction of Dr. Nathan Miller. Beyond these two facilities, I utilize the High Temperature Stable Isotope lab, under the direction of Drs. Jaime Barnes and Dan Breecker, for traditional stable isotope (O, H, C) measurements of pedogenic carbonates and clay minerals.

Li isotopes in mantle xenoliths
NEED info from John Lassiter

Li isotopes in hydrothermal waters
NEED info from Jeff Cullen or Jamie Barnes

Rb-Sr geochronology to constrain the age of high pressure metamorphism
Get geologic background from Miguel and Alissa

Groundwater Li and Sr isotope compositions
NEED info from Daniella Rempe

Contract projects:
Pb isotopic compositions of Archeological artifacts (Chicago Field Museum)
Pb isotopic compositions of mantle xenoliths (Lynne Elkins, University of Nebraska)