Proc. IODP, 344, Data report: isotopic and elemental analyses of pore fluids and carbonates from Sites U1378 and U1380 drilled during CRISP-A Expeditions 334 and 344 in the middle slope offshore Costa Rica

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Chapter contents Abstract Introduction Site description Analytical methods Pore water analyses (carbon, oxygen, and hydrogen isotopes) Solid-phase analyses Elemental analysis of carbonate samples Isotopic analyses of carbonate samples Results Acknowledgments References Figures F1. Map, lithology, seismic data, and calcite-cemented clastic sediment. F2. Results from sediment leaching procedures. F3. ⁸⁷Sr/⁸⁶Sr, elemental composition, δ¹³C, and δ¹⁸O. F4. δ¹⁸O vs. δ¹³C. Tables T1. Pore fluid geochemical data. T2. Carbonate geochemical data. PDF file			Previous \| Next doi:10.2204/iodp.proc.344.208.2019 Data report: isotopic and elemental analyses of pore fluids and carbonates from Sites U1378 and U1380 drilled during CRISP-A Expeditions 334 and 344 in the middle slope offshore Costa Rica¹ Collin Ruark,² Marta E. Torres,² Jesse Muratli,² and Evan A. Solomon³ Abstract Integrated Ocean Drilling Program (IODP) Sites U1378 and U1380, located in the middle slope off Costa Rica, were drilled to characterize the nature, composition, and physical properties of the margin. Drilling results from IODP Expeditions 334 and 344 revealed the material in the margin framework to be well lithified with calcite cemented horizons, which precluded the collection of pore fluids below the slope cover. We report on the elemental and isotopic composition of carbonate leached from cemented sediments underlying the slope cover and on the dissolved inorganic carbon and water isotopic composition of pore fluids in the slope cover. Molar ratios of Sr/Ca (0.21–3.78 mmol/mol), Mn/Ca (2.3–13.8 mmol/mol), and Ba/Ca (0.04–0.84 mmol/mol) in the leached carbonate are shown relative to the pore water distribution of these elements. The ⁸⁷Sr/⁸⁶Sr ratios in carbonate range from 0.70797 to 0.70899. Such nonradiogenic values are consistent with previously published dissolved strontium isotopes, which were attributed to a component of tephra alteration. Pore fluid δ¹³C values range from –22.35‰ to 10.88‰ referenced to Peedee belemnite (PDB), with a marked depletion in ¹³C in the upper sediment (δ¹³C = –22.35‰ PDB at 11.2 meters below seafloor [mbsf]) and enrichment in ¹³C in the sediment section from 20.7 to 425.0 mbsf. Most carbonate samples have δ¹³C values in the range of –2.62‰ to 0.24‰ PDB, and only three samples have δ¹³C values higher than 3.5‰ PDB. The δ¹⁸O of the carbonate samples ranges from –6.35‰ to 2.31‰ PDB, and the δ¹⁸O of the water ranges from –0.71‰ to 3.38‰ referenced to standard mean ocean water (SMOW). ¹ Ruark, C., Torres, M.E., Muratli, J., and Solomon, E.A., 2019. Data report: isotopic and elemental analyses of pore fluids and carbonates from Sites U1378 and U1380 drilled during CRISP-A Expeditions 334 and 344 in the middle slope offshore Costa Rica. In Harris, R.N., Sakaguchi, A., Petronotis, K., and the Expedition 344 Scientists, Proceedings of the Integrated Ocean Drilling Program, 344: College Station, TX (Integrated Ocean Drilling Program). doi:10.2204/iodp.proc.344.208.2019 ² College of Earth, Ocean, and Atmospheric Science, Oregon State University, 104 CEOAS Administrative Building, Corvallis OR 97331-5503, USA. Correspondence author: mtorres@coas.oregonstate.edu ³ School of Oceanography, University of Washington, Seattle WA 98195, USA. Initial receipt: 5 June 2018 Acceptance: 30 October 2018 Publication: 31 January 2019 MS 344-208 Top of page \| Previous \| Next