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No slab-derived CO2 in Mariana Trough back-arc basalts : Implications for carbon subduction and for temporary storage of CO2 beneath slow spreading ridges.\ud

By C.G. Macpherson, D.R. Hilton and K. Hammerschmidt

Abstract

[1] The Southern Mariana Trough is particularly well suited to study mass balance in subduction zones because the flux of material recycled from the subducted slab has been shown to diminish to negligible levels in the southernmost part of the area. We present new He and Ar concentration and isotopic data for 16 back-arc basaltic glasses and combine these with previously published CO2 and H2O concentration and δ13C data to explore the recycling of carbon and light noble gases in the Mariana back arc. Degassing has affected all samples and is particularly extensive in more water-rich samples, i.e., those containing the largest recycled component. The degassing history features three stages: (1) deep degassing which commenced when the melt reached saturation of CO2 and noble gases in the mantle, (2) preeruptive degassing during storage in the crust-mantle transition zone which involved addition of extraneous CO2 to the vapor phase, and (3) eruption. CO2 released during stage 1 was, at least partially, incorporated into wall rock and subsequently remobilized during stage 2 degassing of later magma batches. Reconstructed parental values for 3He/4He, δ13C, CO2/3He, and CO2/40Ar* are indistinguishable from those of mid-ocean ridge basalt. This implies that there is negligible recycling of subducted carbon, helium, or argon into the source of Mariana Trough basalt

Topics: CO2, Noble gas, Mariana Trough, Basalt, Assimilation, Subduction.
Publisher: American Geophysical Union
Year: 2010
DOI identifier: 10.1029/2010GC003293
OAI identifier: oai:dro.dur.ac.uk.OAI2:7556
Journal:

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Citations

  1. (1986). 40Ar‐39Ar dating of young samples, in Dating Young Sediments, edited by
  2. (2005). Absence of a high time‐integrated 3He/(U+Th) source in the mantle beneath continents,
  3. (1995). An experimental study of water and carbon dioxide solubilities in mid‐ocean ridge basaltic liquids. Part II: Applications to degassing,
  4. (1999). Carbon and carbonate in the mantle, in Mantle Petrology: Field Observations and High Pressure Experimentation: A Tribute to
  5. (1990). Carbon isotope constraints on degassing of carbon dioxide from Kilauea volcano,
  6. (1992). Carbon isotope fractionation between calcite, graphite and CO2: An experimental study,
  7. (1994). Carbon isotope variations of CO2 in Lau Basin basalts and ferrobasalts,
  8. (1998). Chemical and isotopic composition of lavas from the Northern Mariana Trough: Implications for magmagenesis in back‐arc basins, doi
  9. (2004). CO2 and 3He in hydrothermal plumes: Implications for mid‐ocean ridge CO2 flux,
  10. (1999). CO2, 13C/12C and H2O variability in natural basaltic glasses: A study comparing stepped heating and FTIR spectroscopic techniques,
  11. (2007). Crystal‐melt partitioning of noble gases (helium, neon, argon, krypton, and xenon) for olivine and clinopyroxene, doi
  12. (2004). Deep global cycling of carbon constrained by the solidus of anhydrous, carbonated eclogite under upper mantle conditions,
  13. (1986). Dissolved carbon dioxide in basaltic glasses: Concentration and speciation, Earth Planet.
  14. (2006). Distinct regional differences in crustal thickness along the axis of the Mariana Trough, inferred from gravity anomalies,
  15. Dunai (2005a), Sources, degassing and contamination of CO2, H2O, He, Ne and Ar in basaltic glasses from Kolbeinsey Ridge, North Atlantic,
  16. (1995). Effects of shallow‐level contamination on the helium isotope systematics of ocean‐island lavas, doi
  17. (2009). Emerging geothermometers for estimating slab surface temperatures,
  18. (2000). Evidence for an 18O‐depleted mantle plume from contrasting 18O/16O ratios of back‐arc lavas from the Manus Basin and Mariana Trough, Earth Planet.
  19. (2010). Experimentally dictated stability of carbonated oceanic crust to moderately great depths in the Earth: Results from the solidus determination in the system CaO‐MgO‐Al2O3‐SiO2‐CO2,
  20. Grönvold (2005b), High‐3He/4He, depleted mantle and low‐d18O, recycled oceanic lithosphere in the source of central Iceland magmatism,
  21. (1993). Helium and argon isotope systematics of the central Lau Basin and Valu Fa Ridge: Evidence of crust/mantle interactions in a backarc basin, doi
  22. (1989). Helium isotope ratios in circum‐Pacific volcanic arcs,
  23. (1985). Helium‐3 and deuterium in back‐arc basalts: Lau Basin and the Mariana Trough, Earth Planet.
  24. (1998). High 3He/4He ratios in the Manus backarc basin: Implications for mantle mixing and the origin of plumes in the western Pacific Ocean,
  25. (1998). Large variations in vent fluid CO2/ 3He ratios signal rapid changes in magma chemistry at Loihi seamount,
  26. (2009). Melt inclusions track pre‐eruption storage and dehydration of magmas at
  27. (2006). Modeling open system metamorphic decarbonation of subducting slabs, doi
  28. (1996). MORB mantle and subduction components interact to generate basalts in the southern Mariana Trough back‐arc basin, doi
  29. (1998). Noble gas and carbon isotopes in Mariana Trough basalt glasses,
  30. (2002). Noble gas isotope geochemistry of mid‐ocean ridge and ocean island basalts: Characterization of mantle source reservoirs, doi
  31. (2007). Oman diopsidites: A new lithology diagnostic of very high temperature hydrothermal circulation in mantle peridotite below oceanic spreading centres, Earth Planet.
  32. (1998). Oxygen isotope variations in Lau Basin lavas,
  33. (1990). Paleoclimatic reconstruction in northern Oman based on carbonate from hyperalkaline groundwaters,
  34. (2002). Recycled dehydrated lithosphere observed in plume‐ influenced mid‐ocean ridge basalt,
  35. (1994). Strong degassing at ridge crests: The behaviour of dissolved carbon and water in basalt glasses at 14°N, Mid‐Atlantic Ridge, Earth Planet.
  36. (2006). The carbon cycle and associated redox processes through time, doi
  37. (2004). The CO2‐He‐Ar‐H2O systematics of the Manus back‐arc basin: Resolving source composition from degassing and contamination effects,
  38. (2005). The role of the global carbonate cycle in the regulation and evolution of the Earth system,
  39. (2001). Volatile (C, N, Ar) variability in MORB and the respective roles of mantle source heterogeneity and degassing:
  40. (1979). Volatiles in submarine volcanic rocks from the Mariana Island arc and trough,

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