@article {781,
	title = {Fluxes of mantle and subducted carbon along convergent plate boundaries},
	journal = {Geophysical Research Letters},
	volume = {23},
	year = {1996},
	note = {Vl370Times Cited:137Cited References Count:39},
	month = {Oct 1},
	pages = {2749-2752},
	abstract = {The potential impact of increases in atmospheric CO2 is a topic of considerable controversy. Even though volcanic emission of CO2 may be very small as compared to anthropogenic emissions, evaluation of natural degassing of CO2 is important for any model of the geochemical C cycle and evolution of the Earth{\textquoteright}s atmosphere. We report here the mantle C flux in subduction zones based on He and C isotopes and CO2/He-3 ratios of high-temperature volcanic gases and medium- and low-temperature fumaroles in circum-Pacific volcanic regions. The calculated volcanic C flux of 3.1x10(12) mol/a from subduction zones is larger than the flux of 1.5x10(12) mol/a from mid-ocean ridges, while contributions from the mantle in subduction zone is only 0.30x10(12) mol/a, equivalent to about 20\% of the C flux in mid-ocean ridges. Since the estimated mantle C flux in hot spot regions is insignificant, 0.029x10(12) mol/a, we propose that the global mantle C flux is 1.8x10(12) mol/a in total. The flux, if accumulated over 4.5 billion year of geological time, amounts to 8.3x10(21) mol which agrees well with 9x10(21) mol of the present inventory of C at the Earth{\textquoteright}s surface. This may support a continuous degassing model of C or the idea that subducted C is recycled into the lower mantle.},
	issn = {0094-8276},
	doi = {10.1029/96gl02260},
	author = {Sano, Y. and Williams, S. N.}
}
@article {863,
	title = {Origin of Carbon in Fumarolic Gas from Island Arcs},
	journal = {Chemical Geology},
	volume = {119},
	year = {1995},
	note = {Qc329Times Cited:227Cited References Count:46},
	month = {Jan 5},
	pages = {265-274},
	abstract = {We have measured He-3/He-4 ratios, delta(13)C-values and CO2/He-3 ratios of fumaroles and hot spring gases in three volcanic areas in Japan. The He-3/He-4 ratios, delta(13)C-values and CO2/He-3 ratios vary from 2.02 R(atm) to 7.55 R(atm) -9.7 parts per thousand to -2.7 parts per thousand and from 7.74.10(9) to 1.18.10(11), respectively. Based on these data and those in the literature, we present the first quantitative estimates of the upper mantle, sediment and limestone including slab components in CO2 of volcanic and hydrothermal fluids from subduction zones. Taking compiled C isotopic data of limestone and organic sediment, assuming that the CO2/He-3 ratio and delta(13)C-value of mid-ocean ridge basalt (MORB) are representative of the upper-mantle component, and that later isotopic and elemental fractionations are minimal, it is possible to deconvolve each fraction of C on the basis of simple mixing equations. Up to 20\% of the carbon in high-temperature volcanic gases in subduction zones is derived from a MORB-type source, while the major fraction of the gases is attributable to CO2 produced by decarbonation of subducted marine limestone and slab carbonate.},
	issn = {0009-2541},
	doi = {10.1016/0009-2541(94)00097-R},
	author = {Sano, Y. and Marty, B.}
}
