Isotopic Systematics of Ocean Island Basalts

Research Topic Introduction

Isotopic systematics of ocean island basalts (OIB) are studied to aid in the understanding of the chemical and dynamic processes operating in the Earth’s mantle at present and in the rock record. The combined processes of plate tectonics, mantle convection, magma generation, crustal recycling and lower mantle exchange contribute to geochemical and isotopic evolution of mantle reservoirs. Each mantle reservoir has a chemical and isotopic fingerprint that can be traced back to the processes and environment that had acted upon it. Factors that can affect this isotopic fingerprint include: partial melting under P-T-X conditions, sediment subduction, crustal recycling, etc. Isotope data becomes extremely useful in determining the source mantle reservoir of OIBs and contributes to the theory of mantle heterogeneity. Specifically, Re-Os, Li, Si, Fe, He and Sr-Nd-Pb isotope data published in numerous geological papers will be synthesized to characterize the behaviour of elements and melting/extraction processes in different environments.

General Outline

 Introduction

  • General info on mantle differentiation/crustal formation
  • How the mantle differentiated over time
  • Crustal processes over time
  • Mantle reservoirs: EMI, EMII, DMM, HIMU

Body

  • Mantle reservoirs and their isotopic characteristics
  • Li in reservoirs
  • Sr, Nd, Pb, He isotope
  • Os isotope trends
  • Fe isotope trends
  • Si isotopes
  • Overall mantle heterogeneity

Conclusion

  • Summarize environment and factors (i.e. crustal recycling) and the isotopes (and source reservoir) that go along with it
  • Reinforce heterogeneous mantle

References

Gibson, S. A., C. W. Dale, D. J. Geist, J. A. Day, G. Brigmann, and K. S. Harpp. “The Influence of Melt Flux and Crustal Processing on Re-Os Isotope Systematics of Ocean Island Basalts: Constraints from Galapagos. “Earth and Planetary Science Letters 449 (2016): 345-59. Web. 8 Feb. 2017.

Graham, D. W. “Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs.” Reviews in Mineralogy and Geochemistry 47.1 (2002): 247-317. Web. 2 Feb. 2017.

Krienitz, M. S., C. D. Garbe-Schonberg, R. L. Romer, A. Meixner, K. M. Haase, and N.Stroncik. “Lithium Isotope Variations in Ocean Island Basalts–Implications for the Development of Mantle Heterogeneity.” Journal of Petrology 53.11 (2012): 2333-347. Web. 2 Feb. 2017.

Pringle, Emily A., Frederick Moynier, Paul S. Savage, Matthew G. Jackson, Manuel Moreira, and James M.d. Day. “Silicon Isotopes Reveal Recycled Altered Oceanic Crust in the Mantle Sources of Ocean Island Basalts.”Geochimica Et Cosmochimica Acta 189 (2016): 282-95. Web. 2 Feb. 2017.

Sun, S. S., and W. F. Mcdonough. “Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes.” Geological Society, London, Special Publications 42.1 (1989): 313-45. Web. 29 Jan. 2017.

Teng, Fang-Zhen, Nicolas Dauphas, Shichun Huang, and Bernard Marty. “Iron Isotopic Systematics of Oceanic Basalts.” Geochimica Et Cosmochimica Acta 107 (2013): 12-26. Web. 29 Jan. 2017.

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