Johnson, C. Boswell Eds. Marine Geology , , Gorman, A. Quaternary shelf structures SE of the South Island, imaged by high-resolution seismic profiling. Geological controls on focused fluid flow through the gas hydrate stability zone on the southern Hikurangi Margin of New Zealand, evidenced from multi-channel seismic data. Campbell, F. Journal of Applied Geophysics , 70 4 , The potential influence of shallow gas and gas hydrates on sea floor erosion of Rock Garden, an uplifted ridge offshore of New Zealand.
Defining the updip extent of the gas hydrate stability zone on continental margins with low geothermal gradients. Journal of Geophysical Research , , B Pecher, I. Focussed fluid flow on the Hikurangi Margin, New Zealand: Evidence from possible local upwarping of the base of gas hydrate stability.
Structure and evolution of the seismically active Ostler Fault Zone New Zealand based on interpretations of multiple high resolution seismic reflection profiles. Tectonophysics , , Seismic imaging of gas conduits beneath seafloor seep sites in a shallow marine gas hydrate province, Hikurangi Margin, New Zealand. Pysklywec, R. Three-dimensional mantle lithosphere deformation at collisional plate boundaries: A subduction scissor across the South Island of New Zealand.
Ghisetti, F. Tectonics , 28 , TC Johnston, L. Hornbach, M. Three-dimensional seismic imaging of the Blake Ridge methane hydrate province: Evidence for large, concentrated zones of gas hydrate and morphologically driven advection. Investigation of the role of gas hydrates in continental slope stability west of Fiordland, New Zealand. Tectonics , 26 , TC An investigation of upper mantle heterogeneity beneath the Archaean and Proterozoic crust of western Canada from Lithoprobe controlled-source seismic experiments.http://web.enduropls.com/qybas-manuale-di-fotografia.php
Department of Geology
Direct seismic detection of methane hydrate on the Blake Ridge. Geophysics , 68 1 , Holbrook, W. Escape of methane gas through sediment waves in a large methane hydrate province. Geology , 30 5 , Breland J. Spectrophotometric procedures for determination of sea water alkalinity using bromocresol green. Carroll J. In : Duan Z. Geochemica Cosmochemica Acta , 56, p. Claypool G. The origin and distribution of methane in sediments. In : Kaplan I. Natural Gases in Marine Sediments. New York, Plenum, p. Clennell M. Demirbas A. Methane hydrates as potential energy resource: Part 1 - Importance, resource and recovery facilities.
Energy Conversion and Management , 51 7 Fontana R. Hydrates offshore Brazil. Annals of the New York Academy of Sciences , Freire A. Marine and Petroleum Geology , 28 10 Gupta A. Marine gas hydrates: their economic and environmental importance.
Current Science , 86 9 Hinrichs K. Methane-consuming archaebacteria in marine sediments.
About this book
Nature , Hiruta A. Geochemical constraints for the formation and dissociation of gas hydrate in an area of high methane flux, eastern margin of the Japan Sea. Earth and Planetary Science Letters , Hensen C. 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. Geochimica et Cosmochimica Acta , 67 14 Sulfate reduction and anaerobic methane oxidation in Black Sea sediments. Joye S.
- A user-friendly guide to multivariate calibration and classification;
- Chasing the Dead: A Novel.
- Defoe’s Review 1704-13, Volume 9.
The anaerobic oxidation of methane and sulfate reduction in sediments from Gulf of Mexico cold seeps. Chemical Geology , Kennicutt M. Gulf of Mexico hydrocarbon seep communities - I. Regional distribution of hydrocarbon seepage and associated fauna. Deep Sea Research Part A. Oceanographic Research Papers , 35 9 Leakage of deep, reservoired petroleum to the near surface on the gulf of Mexico Continental slope. Marine Chemistry , 24 1 Knab N.
Regulation of anaerobic methane oxidation in sediments of the Black Sea.
Biogeosciences , Martins L. Congresso Brasileiro de Geologia. Matsumoto R. Occurrence and exploration of gas hydrate in the marginal seas and continental margin of the Asia and Oceania region. Michaelis W. Microbial reefs in the black sea fueled by anaerobic oxidation of methane. Science , Miller D. Marine and Petroleum Geology , Deep sulfate reduction completely mediated by anaerobic methane oxidation in sediments of the upwelling area off Namibia. Geochimica et Cosmochimica Acta , 62 3 Oliveira S.
Time-frequency spectral signature of Pelotas Basin deep water gas hydrates system. Marine Geophysical Researches , 31 Paull C. Methane-rich plumes on the Carolina continental rise: Associations with gas hydrates. Geology , 23 1 Raiswell R. Chemical model for the origin of minor limestone-shale cycles by anaerobic methane oxidation. Geology , 16 7 Reeburgh W. Black Sea methane geochemistry. Riedel M. Geophysical and geochemical signatures associated with gas hydrate- related venting in the northern Cascadia margin. Geological Society of America Bulletin , Geological control and magnitude of methane ebullition from a high-flux seep area in the Black Sea-the Kerch seep area.
Sad A. Marine gas hydrates evidence along the Brazilian coast. In : Proc. AAPG International conference and exhibition. Sassen R.
Natural Gas Hydrate in Oceanic and Permafrost Environments | NHBS Academic & Professional Books
Bacterial methane oxidation in sea-floor gas hydrate: Significance to life in extreme environments. Geology , 26 9 Silveira D. Bacias sedimentares brasileiras: Bacia de Pelotas. Soloviev V. Water segregation in the course of gas hydrate formation and accumulation in submarine gas-seepage fields. Tomasini J. Assessment of marine gas hydrates and associated free gas distribution offshore Uruguay. Journal of Geological Research , The pore water data and modeling results we use to estimate the methane gradient do not support such a large value.
A significantly steeper methane gradient at the SMT would imply a depth to the top of gas hydrate occurrence that is significantly shallower than that observed at Site U On the other hand, the methane gradient could be somewhat greater than the 2. Therefore, we conservatively estimate that at Site U AOM consumes at least about half of the sulfate in the pore water.
In this section we quantify the effect of different sedimentation rates and different SMT depths to determine if the widely observed absence of methane in the SRZ generally implies that AOM is active. This question is worth exploring because a high enough sedimentation rate could result in low methane concentrations in the SRZ even in the absence of the methane sink due to AOM [ Berner , ]. The methane gradient at the seafloor is very close to the gradient at the base of the SRZ Figure 5.
If the rate of pore fluid burial measured by the sedimentation rate is high enough, it will overcome diffusion, resulting in little or no methane in the SRZ [ Berner , ]. Conversely, a low sedimentation rate results in a small Pe , a methane gradient at the seafloor close to that at the base of the SRZ, and hence methane present in the SRZ.
To get a methane profile approaching that observed at Site U without active AOM, the Peclet number must be raised to at least 5 Figure 9c , which requires an unrealistic sedimentation rate that is more than seventy times that estimated at Site U As the Peclet number is a dimensionless quantity that depends both on the depth of the SMT and the sedimentation rate, the results of Figure 9 can be extended to a range of SMT depths and sedimentation rates Figure It will be only when the upward flux of methane balances the downward flux of sulfate [ Borowski et al. Also, the observation of a linear sulfate gradient from the seafloor to the SMT does not by itself imply that AOM is the dominant sulfate reduction process, as proposed by Borowski et al.
Knowing the fraction of sulfate that serves as the terminal electron acceptor for either the anaerobic oxidation of methane AOM or organoclastic sulfate reduction OSR is important for estimating how much methane may be consumed by AOM and establishing whether sulfate gradients may be indicators of gas hydrate in the underlying sedimentary system.