Mariana blueschist mud volcanism: Implications for conditions within the subduction zone

Fryer, Patricia; Wheat, C. G.; Mottl, Michael J.

doi:10.1130/0091-7613(1999)027<0103:mbmvif>2.3.co;2

Cited by 202 publications

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“…The presence of aragonite, a mineral species unstable under the conditions prevalent at the local seafloor and in Mariana serpentine mud volcanoes (34), strongly supports decarbonation as a CO 2 source. The associated fluids have high alkalinity and H 2 S contents, and their carbon isotope compositions confirm that CO 2 does not derive from the atmosphere but from the breakdown of subducted carbonates (33,35,36).…”

Section: Resultsmentioning

confidence: 84%

Early Archean serpentine mud volcanoes at Isua, Greenland, as a niche for early life

Pons

Quitté

Fujii

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

104

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The Isua Supracrustal Belt, Greenland, of Early Archean age (3.81-3.70 Ga) represents the oldest crustal segment on Earth. Its complex lithology comprises an ophiolite-like unit and volcanic rocks reminiscent of boninites, which tie Isua supracrustals to an island arc environment. We here present zinc (Zn) isotope compositions measured on serpentinites and other rocks from the Isua supracrustal sequence and on serpentinites from modern ophiolites, midocean ridges, and the Mariana forearc. In stark contrast to modern midocean ridge and ophiolite serpentinites, Zn in Isua and Mariana serpentinites is markedly depleted in heavy isotopes with respect to the igneous average. Based on recent results of Zn isotope fractionation between coexisting species in solution, the Isua serpentinites were permeated by carbonate-rich, high-pH hydrothermal solutions at medium temperature (100-300°C). Zinc isotopes therefore stand out as a pH meter for fossil hydrothermal solutions. The geochemical features of the Isua fluids resemble the interstitial fluids sampled in the mud volcano serpentinites of the Mariana forearc. The reduced character and the high pH inferred for these fluids make Archean serpentine mud volcanoes a particularly favorable setting for the early stabilization of amino acids.hydrothermal fluids | serpentinization | origin of life | subduction zone T he discovery of oceanic black smokers and their unique fauna prompted the idea that life may have sprung from hydrothermal vent fields at the bottom of the ocean (1-3). The highly reducing conditions of the vent fields associated with midocean ridges fulfill one of the most stringent conditions for the stabilization of biomolecules. These conditions are a consequence of the metamorphic hydration and oxidation of ultramafic rocks of the oceanic lithosphere-a series of reactions known as serpentinization-that release highly reduced hydrothermal fluids with high concentrations of methane, ammonia, and hydrogen (4, 5). Serpentinization also produces FeNi 3 , which catalyses formation of complex organic compounds (5). Serpentinization thus provides both a source of reduced carbon and a potential energy source, which, together, create an environment suitable for the emergence of the first biomolecules. The vast majority of hydrothermal vent fields, however, especially those hosted by midocean ridges, spout solutions with pH well below the pK of amino acids, which makes them unsuitable for Strecker synthesis (6, 7). Attention therefore shifted toward high-pH hydrothermal vent sites (8, 9) and notably toward the modern vent fluids from the unusual midocean ridge locality of Lost City.The search for an Archean environment in which reducing and high-pH conditions coexist at temperatures appropriate for supporting early life prompted us to investigate Isua serpentinites and their associated hydrothermal carbonates (10). Precipitation of large amounts of carbonates suggests that carbonate ions were abundant in the parent fluid and therefore signals that the pH of this fluid was...

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Section: Resultsmentioning

confidence: 84%

Early Archean serpentine mud volcanoes at Isua, Greenland, as a niche for early life

Pons

Quitté

Fujii

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

104

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“…Tectonic Zones 1-6 in the forearc subduction zone complex are keyed to core images in this figure and to some of the photomicrographs in Figure F3. Figure modified after Fryer et al (1999 Figure F3. Representative samples keyed to zones and cores in Figure F2, Expedition 366.…”

Section: Coring Resultsmentioning

confidence: 99%

“…We mapped changes in the chemical composition of interstitial waters across the Mariana forearc in relation to subduction-related prograde diagenetic and metamorphic reactions that may trigger fluid and elemental releases (Figures F10, F11). Processes that occurred early (shallow) within the subduction system (i.e., Yinazao and Fantangisña Seamounts) were likely dominated by diagenesis and opal dehydration, whereas later processes (deeper) (i.e., Asùt Tesoru Seamount) included decarbonation and clay mineral decomposition Haggerty, 1991;Haggerty and Chaudhuri, 1992;Haggerty and Fisher, 1992;Mottl and Alt, 1992;Fryer et al, 1999;Mottl et al, 2003Mottl et al, , 2004Hulme et al, 2010;Wheat et al, 2008Wheat et al, , 2010. Higher DIC at greater depths-to-slab is likely linked to carbonate decomposition within the slab.…”

Section: Interstitial Water Geochemistrymentioning

confidence: 99%

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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“…For ease of comparison, all elemental concentrations are plotted in millimolar, but B was multiplied by 10 and Na was divided by 10. Figure modified from Fryer et al (1999). Figure F12.…”

Section: Education and Outreachmentioning

confidence: 99%

“…Tectonic Zones 1-6 in the forearc subduction zone complex are keyed to core images in this figure and to photomicrographs in Figure F3. Figure modified after Fryer et al (1999 Figure F3. Representative samples keyed to zones and cores in Figure F2, Expedition 366.…”

Section: Education and Outreachmentioning

confidence: 99%

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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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Mariana blueschist mud volcanism: Implications for conditions within the subduction zone

Cited by 202 publications

References 0 publications

Early Archean serpentine mud volcanoes at Isua, Greenland, as a niche for early life

Early Archean serpentine mud volcanoes at Isua, Greenland, as a niche for early life

Mariana Convergent Margin and South Chamorro Seamount

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