scholarly journals Manganese enrichments near a large gas‐hydrate and cold‐seep field: a record of past redox and sedimentation events

2016 ◽  
Vol 2 (2) ◽  
pp. 142-153 ◽  
Author(s):  
Wesley C. Ingram ◽  
Stephen R. Meyers ◽  
Zhizhang Shen ◽  
Huifang Xu ◽  
Christopher S. Martens
Keyword(s):  
Gas Hydrate ◽  
Cold Seep

THE DISCOVERY OF COLD SEEP CARBONATE IN SHUANGHU REGION, QIANGTANG BASIN AND ITS IMPLICATIONS FOR GAS HYDRATE ACCUMULATION

2014 ◽  
Vol 33 (2) ◽  
pp. 105-110
Author(s):  
Yanju LI ◽  
Jiannan SHI ◽  
Lidong ZHU ◽  
Xiugen FU ◽  
Wenguang YANG ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Cold Seep ◽  
Qiangtang Basin ◽  
Seep Carbonate

Late Pleistocene–Holocene sedimentation surrounding an active seafloor gas-hydrate and cold-seep field on the Northern Gulf of Mexico Slope

2010 ◽  
Vol 278 (1-4) ◽  
pp. 43-53 ◽  
Author(s):  
Wesley C. Ingram ◽  
Stephen R. Meyers ◽  
Charlotte A. Brunner ◽  
Christopher S. Martens
Keyword(s):  
Gulf Of Mexico ◽  
Late Pleistocene ◽  
Gas Hydrate ◽  
Cold Seep ◽  
Northern Gulf Of Mexico

scholarly journals Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 193 ◽  
Author(s):  
Marcelo Ketzer ◽  
Daniel Praeg ◽  
Maria A.G. Pivel ◽  
Adolpho H. Augustin ◽  
Luiz F. Rodrigues ◽  
...  
Keyword(s):  
Gravitational Collapse ◽  
Continental Margin ◽  
Gas Hydrate ◽  
Deep Sea ◽  
Rio Grande ◽  
Cold Seep ◽  
Stability Zone ◽  
The Stability ◽  
Sea Fan ◽  
Hydrate Stability

Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults formed by the gravitational collapse of both depocenters. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements, and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510 and 760 m in the Rio Grande Cone and between 500 and 670 m in the Amazon deep-sea fan), but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocenters. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change requires further investigation. The studied areas provide natural laboratories where these critical processes can be analyzed and quantified.

Diagenesis of magnetic minerals in a gas hydrate/cold seep environment off the Krishna–Godavari basin, Bay of Bengal

2013 ◽  
Vol 340 ◽  
pp. 57-70 ◽  
Author(s):  
P. Dewangan ◽  
N. Basavaiah ◽  
F.K. Badesab ◽  
A. Usapkar ◽  
A. Mazumdar ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Bay Of Bengal ◽  
Cold Seep ◽  
Magnetic Minerals ◽  
Godavari Basin

scholarly journals Cold-Water Corals in Gas Hydrate Drilling Cores from the South China Sea: Occurrences, Geochemical Characteristics and Their Relationship to Methane Seepages

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 742
Author(s):  
Yinan Deng ◽  
Fang Chen ◽  
Niu Li ◽  
Meng Jin ◽  
Jun Cao ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Gas Hydrate ◽  
Bottom Water ◽  
Cold Water ◽  
The South China Sea ◽  
Cold Seep ◽  
Authigenic Carbonates ◽  
Δ13c Values ◽  
Fluid Seepage

Cold-water corals (CWCs) are frequently found at cold seep areas. However, the relationship between fluid seepage and CWC development is not clear. Here, for the first time, we report the occurrences, species identification, mineralogy, carbon and oxygen isotopes, as well as elemental compositions of fossil CWC skeletons from gas-hydrate-bearing sediment in drilling cores from the South China Sea (SCS). Three sites (GMGS-08, GMGS-09B, and GMGS-16) were investigated but CWCs were only found at one site (GMGS-09B). Interestingly, the CWCs were found in three horizons and they were all embedded with authigenic carbonates. Three genera of fossil CWCs (Crispatotrochus sp., Solenosmilia sp. and Enallopsammia sp.) were identified. The CWC fragments are predominantly aragonite. The CWCs exhibit δ13C values between −8.4‰ and −0.6‰ that are significantly higher than δ13C values of the associated seep carbonates (δ13C values with an average of −55.6‰, n = 19), which indicates a carbon source other than methane for the CWCs. It appears that authigenic carbonates provide a substratum for coral colonization. Bathymetric high points, appropriate water temperature and stronger bottom-water currents at site GMGS-09B might be crucial to keep conditions favorable for the growth of CWCs in the studied area. In addition, high trace-element concentrations of Cr, Ni, Pb, U, Ba, Th, and Sr suggest that the CWCs are influenced by strong fluid seepage that can reach the water-sediment interface, and associated microbial activity. Hence, it also becomes evident that CWCs in hydrocarbon-rich seepage areas not only provide a critical constraint on the impact of fluid emission on the bottom water chemistry, but also are likely to be very precise recorders of the end time of cold seep activity.

scholarly journals In situ Raman spectroscopy study of synthetic gas hydrate formed by cold seep flow in the South China Sea

2018 ◽  
Vol 168 ◽  
pp. 197-206 ◽  
Author(s):  
Zengfeng Du ◽  
Xin Zhang ◽  
Shichuan Xi ◽  
Lianfu Li ◽  
Zhendong Luan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
South China Sea ◽  
South China ◽  
Gas Hydrate ◽  
Cold Seep ◽  
Spectroscopy Study ◽  
In Situ Raman Spectroscopy ◽  
In Situ Raman ◽  
Synthetic Gas

scholarly journals Gas Hydrate Accumulation and Occurrence Associated with Cold Seep Systems in the Northern South China Sea: An Overview

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Wei Zhang ◽  
Jinqiang Liang ◽  
Qianyong Liang ◽  
Jiangong Wei ◽  
Zhifeng Wan ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Northern South China Sea ◽  
Cold Seep ◽  
Cold Seeps ◽  
Associated Gas ◽  
China Sea ◽  
Gas Bearing

Studying deep-water cold seep systems is of great significance to gas hydrate exploration due to their close relationship. Various cold seep systems and related gas hydrate accumulations have been discovered in the northern South China Sea in the past three decades. Based on high-resolution seismic data, subbottom profiles, in situ submergence observations, deep drilling and coring, and hydrate gas geochemical analyses, the geological and geophysical characteristics of these cold seep systems and their associated gas hydrate accumulations in the Qiongdongnan Basin, the Shenhu area, the Dongsha area, and the Taixinan Basin have been investigated. Cold seep systems are present in diverse stages of evolution and exhibit various seabed microgeomorphic, geological, and geochemical features. Active cold seep systems with a large amount of gas leakage, gas plumes, and microbial communities and inactive cold seep systems with authigenic carbonate pavements are related to the variable intensity of the gas-bearing fluid, which is usually derived from the deep strata through mud diapirs, mud volcanoes, gas chimneys, and faults. Gas hydrates are usually precipitated in cold seep vents and deeper vertical fluid migration pathways, indicating that deep gas-bearing fluid activities control the formation and accumulation of gas hydrates. The hydrocarbons collected from cold seep systems and their associated gas hydrate reservoirs are generally mixtures of biogenic gas and thermogenic gas, the origin of which is generally consistent with that of deep conventional gas. We also discuss the paragenetic relationship between the gas-bearing fluid and the seafloor morphology of cold seeps and the deep-shallow coupling of gas hydrates, cold seeps, and deep petroleum reservoirs. It is reasonable to conclude that the deep petroleum systems and gas-bearing fluid activity jointly control the development of cold seep systems and the accumulation of gas hydrates in the northern South China Sea. Therefore, the favorable areas for conventional oil and gas enrichment are also prospective areas for exploring active cold seeps and gas hydrates.

scholarly journals Magnetic Mineral Diagenesis in a Newly Discovered Active Cold Seep Site in the Bay of Bengal

2020 ◽  
Vol 8 ◽  
Author(s):  
F. Badesab ◽  
P. Dewangan ◽  
V. Gaikwad
Keyword(s):  
Gas Hydrate ◽  
Fluid Transport ◽  
Hydrate Formation ◽  
Cold Seep ◽  
Anaerobic Oxidation Of Methane ◽  
Magnetic Minerals ◽  
Authigenic Carbonates ◽  
Methane Seepage ◽  
Clay Deposits ◽  
Gas Hydrate Formation

Diagenetically formed magnetic minerals at marine methane seep sites are potential archive of past fluid flow and could provide important constraints on the evolution of past methane seepage dynamics and gas hydrate formation over geologic time. In this study, we carried out integrated rock magnetic, and mineralogical analyses, supported by electron microscope observations, on a seep impacted sediment core to unravel the linkage between greigite magnetism, methane seepage dynamics, and evolution of shallow gas hydrate system in the K-G basin. Three sediment magnetic zones (MZ-1, MZ-2, and MZ-3) have been identified based on the down-core variations in rock magnetic properties. Two events of intense methane seepage are identified. Repeated occurences of authigenic carbonates throughout the core indicate the episodic intensification of anaerobic oxidation of methane (AOM) at the studied site. Marked depletion in magnetic susceptibility manifested by the presence of chemosynthetic shells (Calyptogena Sp.), methane-derived authigenic carbonates, and abundant pyrite grains provide evidences on intense methane seepage events at this site. Fracture-controlled fluid transport supported the formation of gas hydrates (distributed and massive) at this site. Three greigite bearing sediment intervals (G1, G2, G3) within the magnetically depleted zone (MZ-2) are probably the paleo-gas hydrate (distributed-type vein filling) intervals. A strong linkage among clay content, formation of veined hydrate deposits, precipitation of authigenic carbonates and greigite preservation is evident. Hydrate crystallizes within faults/fractures formed as the methane gas migrates through the gas hydrate stability zone (GHSZ). Formation of authigenic carbonate layers coupled with clay deposits restricted the upward migrating methane, which led to the formation of distributed-type vein filling hydrate deposits. A closed system created by veined hydrates trapped the sulfide and limited its availability thereby, causing arrestation of pyritization and favored the formation and preservation of greigite in G1, G2, G3.

scholarly journals Hydrochemical Characteristics and Evolution Mode of Cold Seeps in the Qiongdongnan Basin, South China Sea

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Zhifeng Wan ◽  
Chongmin Chen ◽  
Jinqiang Liang ◽  
Wei Zhang ◽  
Wei Huang ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Hydrate Formation ◽  
Element Distribution ◽  
Qiongdongnan Basin ◽  
Cold Seep ◽  
Cold Seeps ◽  
Remotely Operated Vehicle ◽  
Origin And Evolution ◽  
Gas Hydrate Formation ◽  
Rare Earth Element Distribution

Submarine cold seeps have recently attracted significant attention and are among the most effective indicators of gas hydrate in the oceans. In this study, remotely operated vehicle (ROV) observations, seismic profiles, core sediments, bottom seawater, and fluid vented from cold seeps in the deep-water Qiongdongnan Basin were used to investigate the origin and evolution of cold seeps and their relationships with gas hydrate. At stations A, B, and C, inactive cold seeps with dead clams, cold seep leakage with live clams, and active cold seeps with a rich mussel presence, respectively, were observed. The salinity and Na+ and Cl- concentrations of the cold seeps were different from those of typical seawater owing to gas hydrate formation and decomposition and fluid originating from various depths. The main ion concentrations of the bottom seawater at stations B and C were higher than those at station A, indicating the substantial effects of low-salinity cold seep fluids from gas hydrate decomposition. The Na+-Cl-, K+-Cl-, Mg2+-Cl-, and Ca2+-Cl- diagrams and rare earth element distribution curves of the water samples were strongly affected by seawater. The concentrations of trace elements and their ratios to Cl- in the bottom seawater were high at the stations with cold seeps, suggesting the mixing of other fluids rich in those elements. Biochemical reactions may also have caused the chemical anomalies. Samples of HM-ROV-1 indicated a greater effect of upward cold seep fluids with higher B/Cl-, Sr/Cl-, and Ba/Cl- values. Moreover, the Re/Cl- value varied between fluid vents, possibly due to differences in Re precipitation strength. Differences in cold seep intensity are also believed to occur between areas. The cold seep fluxes changed from large to small before finally disappearing, showing a close connection with gas hydrate formation and decomposition, and influenced the local topography and ecosystems.

scholarly journals A cold seep triggered by a hot ridge subduction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lucía Villar-Muñoz ◽  
Masataka Kinoshita ◽  
Joaquim P. Bento ◽  
Ivan Vargas-Cordero ◽  
Eduardo Contreras-Reyes ◽  
...  
Keyword(s):  
Heat Flow ◽  
Gas Hydrate ◽  
Accretionary Prism ◽  
High Heat ◽  
Cold Seep ◽  
Integrated Analysis ◽  
Active Deformation ◽  
South American Plate ◽  
Ridge Subduction ◽  
Fluid Venting

AbstractThe Chile Triple Junction, where the hot active spreading centre of the Chile Rise system subducts beneath the South American plate, offers a unique opportunity to understand the influence of the anomalous thermal regime on an otherwise cold continental margin. Integrated analysis of various geophysical and geological datasets, such as bathymetry, heat flow measured directly by thermal probes and calculated from gas hydrate distribution limits, thermal conductivities, and piston cores, have improved the knowledge about the hydrogeological system. In addition, rock dredging has evidenced the volcanism associated with ridge subduction. Here, we argue that the localized high heat flow over the toe of the accretionary prism results from fluid advection promoted by pressure-driven discharge (i.e., dewatering/discharge caused by horizontal compression of accreted sediments) as reported previously. However, by computing the new heat flow values with legacy data in the study area, we raise the assumption that these anomalous heat flow values are also promoted by the eastern flank of the currently subducting Chile Rise. Part of the rift axis is located just below the toe of the wedge, where active deformation and vigorous fluid advection are most intense, enhanced by the proximity of the young volcanic chain. Our results provide valuable information to current and future studies related to hydrothermal circulation, seismicity, volcanism, gas hydrate stability, and fluid venting in this natural laboratory.

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