Isotope Geochemistry and Cosmochemistry

Nature of Project(s):

  1. In situ analysis of petrologic materials with the SHRIMP ion microprobes.
  2. Isotopic analyses of geologic materials using chemical separation methods and thermal ionization mass spectrometry (TIMS) or plasma source mass spectrometry  (ICPMS)

Essential Background:

Suitable for students with interests in Geochemistry or Planetary Science.  

Students using solution methods will perform demanding work in a clean chemistry lab and should have a chemistry background or previous experience.

EMSC8022 (Advanced Analytical Techniques) and EMSC 8024 (Foundations of Analytical Techniques and Data Science).

Background: 

Isotope abundances provide key information concerning timing and processes operating in a wide range of terrestrial and extraterrestrial environments. In situ analysis by SHRIMP ion microprobes allow isotope ratio determination with micron scale resolution in mineral context. This technique provides excellent sensitivity and is the least invasive method of analysis for many systems including O, C, S stable isotope analyses, as well as trace element and U-Th-Pb in appropriate accessory minerals.

Isotope analysis of dissolved and chemically separated whole rock or separated mineral samples is the method of choice for isotopic dating and tracing with radiogenic isotope systems such as Lu-Hf, Sm-Nd and U-Th-Pb. It yields precise timing of formation and the ages of different source materials contributing to formation of rocks.

Possible Future Research Avenues: 

  1. Current work is focusing on our unique capabilities in minor isotope analysis of O (17O) and sulphur (33S and 36S). This has wide applicability in constraining the environments on early Earth, Mars, and planetary volatiles in the early solar system.  Sulphur isotope analyses provide controls on the formation of large sulphide deposits. 
  2. Current work is focusing on the use of Nd, Sr and Hf isotopic compositions of sediments from drill cores to determine the changing sources of materials contributing to Proterozoic basins to try to link this with tectonic events.
  3. Current work is focusing on precise determination of ages of meteorite components to understand the timing and duration of early solar system events.
  4. Current work is focusing on better determination of the physical and chemical foundations of isotope geochemistry: this includes more accurate and precise half-lives for long-lived radioisotopes, absolute isotopic ratios, and mechanisms and patterns of isotope fractionation.  
     

 

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