The Subduction Margin Carbon Cycle: A Preliminary Assessment of the Distribution Patterns of Multicycle Carbon

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The role of recycled fossil C in elemental budgets and organic C behavior on active margins is not known beyond the mid-slope. Fossil C would be expected to persist longer in surface environments than younger materials because of its low reactivity. Its persistence would influence the global C and O2-cycles, product formation during deep burial, and the interpretation of sedimentary organic geochemical records. This exploratory study of the three GeoPRISMS Subduction Cycles and Deformation (SCD) primary focus sites, the Alaskan, Cascadia and Hikurangi Margins, has the specific objective of developing a preliminary assessment of the distribution of multicycle C at the sites. Samples will come primarily from archives held by the National Institute of Water and Atmospheric Research of New Zealand and the Deep Sea Drilling Project/Ocean Drilling Project repositories in the US. In addition, sample collection and analysis is proposed for the planned Integrated Ocean Drilling Program expedition to the Alaskan margin in 2013. Analyses of samples will include Raman and FTIR microscopy, stable carbon and radiocarbon isotopic measurements, and elemental (H/C) determinations. The survey to be generated by this project will be a first look at multicycle C across several active margin environments beyond the mid-slope. The baseline information will be used to plan future C-cycling and paleoenvironmental studies.Broader Impacts: This project and participation in the GeoPRISMS program will be valuable educational and professional experiences for the graduate student involved. Supplemental REU funding will be sought to engage an undergraduate in the research. A GIS-based education tool for the high school study of the global C-cycle will be developed in collaboration with Northwestern?s Office of STEM Education Partnerships.