Organic carbon deposition and its control on iron sulfide formation of the southern East China Sea continental shelf sediments

Lin, Shu-Yen; Huang, Kuo-Ming; Chen, Shin-Kuan

doi:10.1016/s0278-4343(99)00088-6

Cited by 73 publications

(34 citation statements)

References 35 publications

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“…1 cm/ka, see Reading, 1996), much higher rates have been reported for both continental slope and rise worldwide (e.g., N23 cm/ka during the past 90 ka at ODP Leg 175 Site 1079, 1.6-10 cm/ka during the past 1.1 Ma at ODP Leg 175 Site 1080, 7-21 cm/ka during the past 6 Ma at ODP Leg 175 Site 1082, all on the West African continental margin, Shipboard Scientific Party, 1998b,c,d), 15-19 cm/ka on the Ebro continental margin, Nelson, 1990) as well as for numerous shelf areas (e.g. N24 cm/ky during the past 90 ka at ODP Leg 175 Site 1078, Shipboard Scientific Party, 1998a; 100 cm/ka in the Gulf of Mexico, Morse et al, 2002;170-680 cm/ka on the East China Sea continental shelf, Lin et al, 2000;9-82 cm/ka on the Ebro continental shelf, Nelson, 1990). Hence, the observed sedimentation rate of 2 cm/ka at the southern South African continental margin is very small.…”

Section: Discussionmentioning

confidence: 99%

Sedimentary deposits on the southern South African continental margin: Slumping versus non-deposition or erosion by oceanic currents?

Uenzelmann-Neben¹,

Huhn²

2009

Marine Geology

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Seismic profiles extending from the southern South African shelf into the deep sea reveal a strong erosional activity, which affects large parts of the continental margin. Quaternary to Oligocene units and, in places, the complete sedimentary column appear to have been removed. Mass movements were previously considered as the origin of this erosion. However, structures indicating slumping can be identified in only a few places. The erosional activity is confined to specific water depths, which correlate well with the activity levels of water masses observed here. We thus suggest that the Agulhas Current, Antarctic Intermediate Water, North Atlantic Deep Water, and Antarctic Bottom Water have intensively shaped the sedimentary units over a long period. This indicates a stable circulation comparable to that at present day since the Neogene.

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Section: Discussionmentioning

confidence: 99%

Sedimentary deposits on the southern South African continental margin: Slumping versus non-deposition or erosion by oceanic currents?

Uenzelmann-Neben¹,

Huhn²

2009

Marine Geology

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“…Much organic material is also deposited, such as that found in the Southwest Taiwan Basin in the SCS. In the anoxic environment, anoxic sulfate reduction and permanent burial are the two primary pathways that determine the fate of sedimentary organic carbon in shelf sediments [20]. Within anoxic sediment, organic carbon is usually degraded to CH 4 , CO 2 and H 2 by methanogenic bacteria.…”

Section: Discussionmentioning

confidence: 99%

Nano-sized graphitic carbon in authigenic tube pyrites from offshore southwest Taiwan, South China Sea, and its implication for tracing gas hydrate

Zhang

Sun

et al. 2011

Chin. Sci. Bull.

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Gas hydrates are a significant energy resource and are usually detected by bottom simulating reflection and submarine geochemical anomalies. Authigenic minerals are related to gas hydrates, with carbonates, sulfates and sulfides being important tracing minerals. Authigenic tubular pyrites were collected from offshore southwest Taiwan in the South China Sea, and were investigated by scanning electron microscopy(SEM) and high-resolution transmission electron microscopy (HRTEM). Authigenic tubular pyrite was composed of framboidal pyrite, within which nanosized graphitic carbon of low crystallinity was discovered. The graphitic carbon coexisted with pyrite and had a texture similar to carbon nanotubes and nanocones, indicating that they likely precipitated from carbon supersaturated C-H-O fluid. Pyrite may act as a catalyst for the conversion of CH 4 to C. The discovery of nanosized graphitic carbon in pyrite indicated it was deposited in sediments that were supersaturated with methane fluid. Thus, nanosized graphitic carbon may be another tracing species for submarine gas hydrates. The discovery of nanosized graphitic carbon deposited in a low temperature environment will enlighten our understanding of the laboratory synthesis and industrial production of graphitic carbon.nano-sized graphitic carbon, authigenic tube pyrite, gas hydrate, South China Sea Citation:Zhang M, Sun X M, Xu L, et al. Nano-sized graphitic carbon in authigenic tube pyrites from offshore southwest Taiwan, South China Sea, and its implication for tracing gas hydrate. Chinese Sci Bull, 2011Bull, , 56: 2037Bull, −2043Bull, , doi: 10.1007 Gas hydrates are an ice-like crystalline material consisting predominantly of methane and water molecules, and are formed under high pressure and low temperature on continental slopes/rises [1]. As a newly discovered clean energy source during the last two decades, gas hydrates are gaining worldwide attention on account of their importance in energy exploration, and through increasing awareness of seafloor structure geo-hazards (stability) and global climate change. Gas hydrates predominantly occur at depths of 300-3000 m around the edges of continents and in marginal marine basins. Most information on the distribution, concentration, composition and origin of gas hydrates in deep marine sediments comes from geophysical evidence such as bottom simulating reflection and strong seafloor acoustic reflectivity. These techniques are commonly used to infer the distribution of gas hydrates on continental margins, in addition to gas hydrate samples collected during the deep sea drilling project and ocean drilling program. Pyrite is a common authigenic mineral within the marine sediments of the continental margin. It is the product of

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“…Meanwhile, the HCO 3 − concentration increases in the pore water with decomposition of organic matter. Sulphide forms with free HS − and low-valence iron, and finally sulphide transforms into pyrite [45,46]. Sassen et al found many framboidal pyrites, and pyrite granules in sediments from a gas hydrate area in the Golf of Mexico and suggested that the strong anaerobic methane oxidation (AOM) contributes to pyrite formation in sediments [5].…”

Section: Authigenic Minerals and Microstructures Of Sedimentsmentioning

confidence: 99%

“…Furthermore, AOM changes the geochemical conditions and results in the rapid deposition of miscellaneous carbonates including aragonite, Mg-calcite, and dolomite [51]. Meanwhile, pyrite formation results from the reaction of H 2 S, derived from bacterial sulphate reduction, with reactive iron [45,46]. Precipitation of aragonite, Mg-calcite, and pyrite is the result of processes related to the presence of methane seep in the northern Black sea [1,8].…”

Section: Authigenic Minerals and Microstructures Of Sedimentsmentioning

confidence: 99%

Early Diagenesis Records and Pore Water Composition of Methane-Seep Sediments from the Southeast Hainan Basin, South China Sea

et al. 2011

Journal of Geological Research

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Several authigenic minerals were identified by XRD and SEM analyses in shallow sediments from the Southeast Hainan Basin, on the northern slope of South China Sea. These minerals include miscellaneous carbonates, sulphates, and framboidal pyrite, and this mineral assemblage indicates the existence of gas hydrates and a methane seep. The assemblage and fabric features of the minerals are similar to those identified in cold-seep sediments, which are thought to be related to microorganisms fostered by dissolved methane. Chemical composition of pore water shows that the concentrations of SO 2− 4 , Ca 2+ , Mg 2+ , and Sr 2+ decrease clearly, and the ratios of Mg 2+ to Ca 2+ and Sr 2+ to Ca 2+ increase sharply with depth. These geochemical properties are similar to those where gas hydrates occur in the world. All results seem to indicate clearly the presence of gas hydrates or deep water oil (gas) reservoirs underneath the seafloor.

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Organic carbon deposition and its control on iron sulfide formation of the southern East China Sea continental shelf sediments

Cited by 73 publications

References 35 publications

Sedimentary deposits on the southern South African continental margin: Slumping versus non-deposition or erosion by oceanic currents?

Sedimentary deposits on the southern South African continental margin: Slumping versus non-deposition or erosion by oceanic currents?

Nano-sized graphitic carbon in authigenic tube pyrites from offshore southwest Taiwan, South China Sea, and its implication for tracing gas hydrate

Early Diagenesis Records and Pore Water Composition of Methane-Seep Sediments from the Southeast Hainan Basin, South China Sea

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