Acoustic investigations of mud volcanoes in the Sorokin Trough, Black Sea

Krastel, Sebastian; Spieß, V.; Ivanov, M.K.; Weinrebe, Wilhelm; Bohrmann, Gerhard; Shashkin, Pavel; Heidersdorf, F.

doi:10.1007/s00367-003-0143-0

Cited by 69 publications

(51 citation statements)

References 19 publications

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“…In contrast, GRA density increases in Holes U1492A, U1492B, and U1496A suggest this overpressure effect associated with the conduit system is not effective 50 to 100 m from the area with the most active fluid discharge. A width of less than ~100 m for the active conduit at Yinazao and Asùt Tesoru Seamounts is consistent with conduit diameters described for other mud volcanoes, which are considerably smaller than the size of the mud volcanoes themselves (Krastel et al, 2003).…”

Section: Physical Propertiessupporting

confidence: 81%

Mariana Convergent Margin and South Chamorro Seamount

Fryer¹,

Wheat²,

Williams³

et al. 2018

Proceedings of the International Ocean Discovery Program

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Geologic processes at convergent plate margins control geochemical cycling, seismicity, and deep biosphere activity in subduction zones and suprasubduction zone lithosphere. International Ocean Discovery Program Expedition 366 was designed to address the nature of these processes in the shallow to intermediate depth of the Mariana subduction channel. Although no technology is available to permit direct sampling of the subduction channel of an intraoceanic convergent margin at depths up to 19 km, the Mariana forearc region (between the trench and the active volcanic arc) provides a means to access materials from this zone.Active conduits, resulting from fractures in the forearc, are prompted by along-and across-strike extension that allows slab-derived fluids and materials to ascend to the seafloor along associated faults, resulting in the formation of serpentinite mud volcanoes. Serpentinite mud volcanoes of the Mariana forearc are the largest mud volcanoes on Earth. Their positions adjacent to or atop fault scarps on the forearc are likely related to the regional extension and vertical tectonic deformation in the forearc. Serpentinite mudflows at these volcanoes include serpentinized forearc mantle clasts, crustal and subducted Pacific plate materials, a matrix of serpentinite muds, and deep-sourced formation fluid. Mud volcanism on the Mariana forearc occurs within 100 km of the trench, representing a range of depths and temperatures to the downgoing plate and the subduction channel. These processes have likely been active for tens of millions of years at the Mariana forearc and for billions of years on Earth.At least 19 active serpentinite mud volcanoes have been located in the Mariana forearc. Two of these mud volcanoes are Conical and South Chamorro Seamounts, which are the farthest from the Mariana Trench at 86 and 78 km, respectively. Both seamounts were cored during Ocean Drilling Program Legs 125 and 195, respectively. Data from these two seamounts represent deeper, warmer examples of the continuum of slab-derived materials as the Pacific plate subducts, providing a snapshot of how slab subduction affects fluid release, the composition of ascending fluids, mantle hydration, and the metamorphic paragenesis of subducted oceanic lithosphere. Data from the study of these two mud volcanoes constrain the pressure, temperature, and composition of fluids and materials within the subduction channel at depths of up to 19 km. Understanding such processes is necessary for elucidating factors that control seismicity in convergent margins, tectonic and magma genesis processes in the volcanic arc and backarc areas, fluid and material fluxes, and the nature and variability of environmental conditions that impact subseafloor microbial communities.Expedition 366 focused on data collection from cores recovered from three serpentinite mud volcanoes that define a continuum of subduction-channel processes to compare with results from drilling at the two previously cored serpentinite mud volcanoes and with previously ...

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Section: Physical Propertiessupporting

confidence: 81%

Mariana Convergent Margin and South Chamorro Seamount

Fryer¹,

Wheat²,

Williams³

et al. 2018

Proceedings of the International Ocean Discovery Program

View full text Add to dashboard Cite

show abstract

“…In contrast, GRA density increases in Holes U1492A, U1492B, and U1496A suggest this overpressure effect associated with the conduit system is not effective 50 to 100 m from the area with the most active fluid discharge. A width of less than ~100 m for the active conduit at Yinazao and Asùt Tesoru Seamounts is consistent with conduit diameters, which are considerably smaller than the size of the mud volcanoes themselves and those described for other mud volcanoes (Krastel et al, 2003).…”

Section: Physical Propertiessupporting

confidence: 70%

Untitled

Fryer¹,

Wheat²,

Williams³

et al. 2017

International Ocean Discovery Program Preliminary Report

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Geologic processes at convergent plate margins control geochemical cycling, seismicity, and deep biosphere activity in subduction zones and suprasubduction zone lithosphere. International Ocean Discovery Program (IODP) Expedition 366 was designed to address the nature of these processes in the shallow to intermediate depth of the Mariana subduction channel. Although no technology is available to permit direct sampling of the subduction channel of an intraoceanic convergent margin at depths up to 18 km, the Mariana forearc region (between the trench and the active volcanic arc) provides a means to access this zone.Active conduits, resulting from fractures in the forearc, are prompted by along-and across-strike extension that allows slab-derived fluids and materials to ascend to the seafloor along associated faults, resulting in the formation of serpentinite mud volcanoes. Serpentinite mud volcanoes of the Mariana forearc are the largest mud volcanoes on Earth. Their positions adjacent to or atop fault scarps on the forearc are likely related to the regional extension and vertical tectonic deformation in the forearc. Serpentinite mudflows at these volcanoes include serpentinized forearc mantle clasts, crustal and subducted Pacific plate materials, a matrix of serpentinite muds, and deep-sourced formation fluid. Mud volcanism on the Mariana forearc occurs within 100 km of the trench, representing a range of depths and temperatures to the downgoing plate and the subduction channel. These processes have likely been active for tens of millions of years at this site and for billions of years on Earth.At least 10 active serpentinite mud volcanoes have been located in the Mariana forearc. Two of these mud volcanoes are Conical and South Chamorro Seamounts, which are the furthest from the Mariana Trench at 86 and 78 km, respectively. Both seamounts were cored during Ocean Drilling Program (ODP) Legs 125 and 195, respectively. Data from these two seamounts represent deeper, warmer examples of the continuum of slab-derived materials as the Pacific plate subducts, providing a snapshot of how slab subduction affects fluid release, the composition of ascending fluids, mantle hydration, and the metamorphic paragenesis of subducted oceanic lithosphere. Data from the study of these two mud volcanoes constrain the pressure, temperature, and composition of fluids and materials within the subduction channel at depths of about 18 to 19 km. Understanding such processes is necessary for elucidating factors that control seismicity in convergent margins, tectonic and magma genesis processes in the forearc and volcanic arc, fluid and material fluxes, and the nature and variability of environmental conditions that impact subseafloor microbial communities.Expedition 366 centered on data collection from cores recovered from three serpentinite mud volcanoes that define a continuum of subduction-channel processes defined by the two previously cored serpentinite mud volcanoes and the trench. Three serpentinite mud volcanoes (Yinazao, Fa...

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“…shallow gas fronts, enhanced reflections, acoustic blanking) or potential gas or fluid conduits (e.g. faults, diapirs) (Judd and Hovland, 1992;Orange and Breen, 1992;Yun et al, 1999;Garcia-Gil et al, 2002;Van Rensbergen et al, 2002;Krastel et al, 2003;Naudts et al, 2006;Judd and Hovland, 2007). Direct localization of seeps, i.e.…”

Section: Introductionmentioning

confidence: 99%

Anomalous sea-floor backscatter patterns in methane venting areas, Dnepr paleo-delta, NW Black Sea

et al. 2008

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The relation between acoustic seafloor backscatter and seep distribution is examined by integrating multibeam backscatter data and seep locations detected by single-beam echosounder. This study is further supported by side scan sonar recordings, high-resolution 5 kHz seismic data, pore-water analysis, grain-size analysis and visual seafloor observations. The datasets were acquired during the 2003 and 2004 expeditions of the EC-funded CRIMEA project in the Dnepr paleo-delta area, northwestern Black Sea.More than 600 active methane seeps were hydro-acoustically detected within a small (3.96 km by 3.72 km) area on the continental shelf of the Dnepr paleo-delta in water depths ranging from -72 m to -156 m. Multibeam and side scan sonar recordings show backscatter patterns that are clearly associated with seepage or with a present dune area. Seeps generally occur within medium-to highbackscatter areas which often coincide with pockmarks.High-resolution seismic data reveal the presence of an undulating gas front, i.e. the top of the free gas in the subsurface, which domes up towards and intersects the seafloor at locations where gas seeps and medium-to high-backscatter values are detected. Pore-water analysis of 4 multi-cores, taken at different backscatter intensity sites, shows a clear correlation between backscatter intensity and dissolved methane fluxes. All analyzed chemical species indicate increasing anaerobic oxidation of methane (AOM) from medium-to high-backscatter locations. This is confirmed by visual seafloor observations, showing bacterial mats and authigenic carbonates formed by AOM. Grain-size analysis of the 4 multi-cores only reveals negligible variations between the different backscatter sites.Integration of all datasets leads to the conclusion that the observed backscatter patterns are the result of ongoing methane seepage and the precipitation of methane-derived authigenic carbonates (MDACs) caused by AOM. The carbonate formation also appears to lead to a gradual (self-)sealing of the seeps by cementing fluid pathways/horizons followed by a relocation of the bubble-releasing locations. KeywordsMethane seeps; acoustic seafloor backscatter; anaerobic oxidation of methane; bacterial mats; pockmarks; methane-derived authigenic carbonates

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Acoustic investigations of mud volcanoes in the Sorokin Trough, Black Sea

Cited by 69 publications

References 19 publications

Mariana Convergent Margin and South Chamorro Seamount

Mariana Convergent Margin and South Chamorro Seamount

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Anomalous sea-floor backscatter patterns in methane venting areas, Dnepr paleo-delta, NW Black Sea

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