Abstract
This is a report of the study of the authigenic sulfide minerals and their sulfur isotopes in a sediment core (NH-1) collected on the northern continental slope of the South China Sea, where other geophysical and geochemical evidence seems to suggest gas hydrate formation in the sediments. The study has led to the findings: (1) the pyrite content in sediments was relatively high and its grain size relatively large compared with that in normal pelagic or hemipelagic sediments; (2) the shallowest depth of the acid volatile sulfide (AVS) content maximum was at 437.5 cm (>2 μmol/g), which was deeper than that of the authigenic pyrite content maximum (at 141.5–380.5 cm); (3) δ 34S of authigenic pyrite was positive (maximum: +15‰) at depth interval of 250–380 cm; (4) the positive δ 34S coincided with pyrite enrichment. Compared with the results obtained from the Black Sea sediments by Jorgensen and coworkers, these observations indicated that at the NH-1 site, the depth of the sulfate-methane interface (SMI) would be or once was at about 437.5–547.5 cm and the relatively shallow sMI depth suggested high upward methane fluxes. This was in good agreement with the results obtained from pore water sulfate gradients and core head-space methane concentrations in sediment cores collected in the area. All available evidence suggested that methane gas hydrate formation may exist or may have existed in the underlying sediments.
Similar content being viewed by others
References
Berner R A. Early Diagenesis: A Theoretical Approach. Princeton. New Jersey: Princeton University Press, 1980. 241
Jorgensen B B. Mineralization of organic matter in the sea bed—the role of sulphate reduction. Nature, 1982, 296(5858): 643–645
Canfield D E. Organic matter oxidation in marine sediments. In: Interactions of C, N, P and S Biogeochemical Cycles and Global Change. Berlin: Springer, 1993
Jorgensen B B, Bottcher M E, Luschen H, et al. Anaerobic methane oxidation and a deep H2S sink generate isotopically heavy sulfides in Black Sea sediments. Geochim Cosmochim Acta, 2004, 68(9): 2095–2118
Aharon P, Fu B. Microbial sulfate reduction rates and sulfur and oxygen isotope fractionations at oil and gas seeps in deepwater Gulf of Mexico. Geochim Cosmochim Acta, 2000, 64(2): 233–246
Borowski W S, Paull C K, Ussler I W. Global and local variations of interstitial sulfate gradients in deep-water, continental margin sediments: Sensitivity to underlying methane and gas hydrates. Marine Geology, 1999, 159(1–4): 131–154
Jiang S Y, Yang T, Xue Z C, et al. Chlorine and sulfate concentrations in pore waters from marine sediments in the north margin of the South China Sea and their implications for gas hydrate exploration. Geoscience (in Chinese), 2005, 19(1): 45–54
Wang J S, Suess E, Rickert D. Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North Pacific. Sci China Ser D-Earth Sci, 2004, 47(3): 280–288
Gerald R D. Sulfate profiles and barium fronts in sediment on the Blake Ridge: Present and past methane fluxes through a large gas hydrate reserv. Geochim Cosmochim Acta, 2001, 65(4): 529–543
Hsieh Y P, Shieh Y N. Analysis of reduced inorganic sulfur by diffusion methods: improved apparatus and evaluation for sulfur isotopic studies. Chemical Geology, 1997, 137(3–4): 255–261
Hsieh Y P, Chung S W, Tsau Y J, et al. Analysis of sulfides in the presence of femic minerals by diffusion methods. Chemical Geology, 2002, 182(2–4): 195–201
Nedwell D B, Abram J W. Bacterial sulphate reduction in relation to sulphur geochemistry in two contrasting areas of saltmarsh sediment. Estuar Coast Mar Sci, 1978, 6(4): 341–351
Canfield D E. Reactive iron in marine sediments. Geochim Cosmochim Acta, 1989, 53(3): 619–632
Taillefert M, Bono A B, Luther G W. Reactivity of freshly formed Fe(III) in synthetic solutions and (pore)waters: Voltammetric evidence of an aging process. Environm Sci Tech, 2000, 34(11): 2169–2177
Luther G W, Kostka J E, Church T M, et al. Seasonal iron cycling in the salt-marsh sedimentary environment: the importance of ligand complexes with Fe(II) and Fe(III) in the dissolution of Fe(III) minerals and pyrite, respectively. Marine Chemistry, 1992, 40(1–2): 81–103
Gagnon C, Mucci A, Pelletier E. Anomalous accumulation of acid-volatile sulphides (AVS) in a coastal marine sediment, Saguenay Fjord, Canada. Geochim Cosmochim Acta, 1995, 59(13): 2663–2675
Hensen C, Zabel M, Pfeifer K, et al. Control of sulfate pore-water profiles by sedimentary events and the significance of anaerobic oxidation of methane for the burial of sulfur in marine sediments. Geochim Cosmochim Acta, 2003, 67(14): 2631–2647
Cecile M P, Shakur M A, Krouse H R. The isotopic composition of western Canadian barites and the possible derivation of oceanic sulfate delta-S-34 and delta-O-18 age curves. Can J Earth Sci, 1983, 20(10): 1528–1535
Bottcher M E, Smock A M, Cypionka H. Sulfur isotope fractionation during experimental precipitation of iron(II) and manganese(II) sulfide at room temperature. Chemical Geology, 1998, 146(3–4): 127–134
Boning P, Brumsack H J, Bottcher M E, et al. Geochemistry of Peruvian near-surface sediments. Geochim Cosmochim Acta, 2004, 68(21): 4429–4451
Butler I, Bottcher M E, David R, et al. Sulfur isotope partitioning during pyrite formation. Abstracts Paper Am Chem Soc, 2003, 225: U913–U913
Kemp A L W, Thode H G. The mechanism of the bacterial reduction of sulphate and of sulphite from isotope fractionation studies. Geochim Cosmochim Acta, 1968, 32(1): 71–91
Habicht K S, Canfield D E. Sulphur isotope fractionation in modern microbial mats and the evolution of the sulphur cycle. Nature, 1996, 382(6589): 342–343
Habicht K S, Canfield D E. Sulfur isotope fractionation during bacterial sulfate reduction in organic-rich sediments. Geochim CosmochimActa, 1997, 61(24): 5351–5361
Jorgensen B B. A theoretical model of the stable sulfur isotope distribution in marine sediments. Geochim Cosmochim Acta, 1979, 43(3): 363–374
Neretin L N, Bottcher M E, Jorgensen B B, et al. Pyritization processes and greigite formation in the advancing sulfidization front in the upper Pleistocene sediments of the Black Sea. Geochim Cosmochim Acta, 2004, 68(9): 2081–2093
Liu J, Liu H F, Liao Z L, et al. Distribution of sulfides in shallow sediments in Dongsha area, South China Sea, and its relationship to gas hydrates. Earth Sci Front (in Chinese), 2005, 12(3): 258–262
Zhang G X, Huang Y Y, Zhu Y H, et al. Prospect of gas hysrate resources in the South China Sea. Mar Geo & Qua Geo (in Chinese), 2002, 22(1): 75–81
Guo T M, Wu B H, Zhu Y H, et al. A review on the gas hydrate research in China. J Petro Sci Eng, 2004, 41(1–3): 11–20
Yang T, Xue Z C, Yang J H, et al. Oxygen and hydrogen isotopic compositions of pore water from marine sediments in the northern South China Sea. Act Geo Sin (in Chinese), 2003, 24(6): 511–514
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KZCX3-SW-219), the National Natural Science Foundation of China (Grant No. 40376038), and the “100 Talents Programme” of the Chinese Academy of Sciences
About this article
Cite this article
Pu, X., Zhong, S., Yu, W. et al. Authigenic sulfide minerals and their sulfur isotopes in sediments of the northern continental slope of the South China Sea and their implications for methane flux and gas hydrate formation. CHINESE SCI BULL 52, 401–407 (2007). https://doi.org/10.1007/s11434-007-0043-1
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11434-007-0043-1