Title: Sample description and geochemistry collected from Mariana forearc boreholes with the HOG sampler
Sample description and geochemistry collected from Mariana forearc boreholes with the HOG sampler Project Name: Collaborative Research: Collaborative Research: Characterization of Subduction Channel Processes, Borehole Sampling at Active Serpentinite Mud Volcanoes on the Mariana Funding: NSF-OCE-1921654 Susan Lang, Woods Hole Oceanographic InstitutionForearc NSF-OCE-1922671 Geoff Wheat, University of Alaska Fairbanks NSF-OCE-1921361 Jeff Seewald, Woods Hole Oceanographic Institution Permits: Mariana Trench National Wildlife Refuge, U.S. Fish & Wildlife Service, Department of the Interior Permit Number: 12541-22009 Project goals: The overarching goal of the project was to understand the reaction processes that occur at depth during subduction. Boreholes drilled during the recent International Ocean Discovery Program Expedition 366 were targeted to collect pristine fluids. The specific goals of the project were to (1) determine the water-rock reactions that control the chemical composition of deep-sourced fluids ascending from atop a subducting slap (2) identify the processes that regulate the nonbiological formation of methane, and assess its potential metabolic impact (3) characterize the origin and abundance of organic carbon molecules to constrain redox and pH conditions within the subduction channel and shallow subsurface environment and (4) relate the permeability of fluid pathways to seamount structure Samples were collected during a 25 day expedition with a deep-sea submersible. A CORK-Lite was be deployed at three newly cased boreholes: U1492D (Yinazao), U1497D (Fantangisña), and U1496C (Asùt Tesoru). Fluids discharging from these three new boreholes, and a fourth already cased borehole (U1200C, South Chamorro), were collected for inorganic and organic geochemical analysis. Dataset Description: Table 1. Sample Logs. Summary of samples collected by the Hydrothermal Organic Geochemistry (HOG) sampler on R/V Kilo Moana (KM22-14) with ROV Jason, on dives J2_1468 through J2_1478, November 20, 2022 to December 17, 2022. Fluid samples were collected into either 2 L or 11 L kynar bags that were acid washed (10% HCl soak overnight, followed by through rinsing, overnight Milli-Q soak, and further rinsing). Additional samples were collected by filtering fluids in situ through sterivex filters, flat filters loaded with RNA later, or copper tubes used for helium gas sampling. Partway through the expedition, a long tube was added to the intake of the sampler that reached deeper into the borehole. Samples collected after this addition recovered higher purity fluids. N.D. is no data. Table 2. Geochemical Data including pH, alkalinity, hydrolizable amino acids, free amino acids, total acetate, total formate, stable isotopes of dissolved inorganic carbon (δ13C), and stable isotopes of water (δ2H and δ18O). more »« less
Wheat, C.G.; Fournier, T.; Paul, C.; Menzies, C.; Price, R.E.; Ryan, J.; Sissman, O.
(, Proceedings of the International Ocean Discovery Program)
null
(Ed.)
International Ocean Discovery Program (IODP) Expedition 366 focused, in part, on the study of geochemical cycling, matrix alteration and transport, and deep biosphere processes in the Mariana subduction zone. This research was accomplished by sampling the summit and flank regions of three active serpentinite mud volcanoes in the Mariana forearc: Yinazao (Blue Moon), Fantangisña (Celestial), and Asùt Tesoro (Big Blue) Seamounts. These mud volcanoes represent a transect with increasing distance from the trench. Because these mud volcanoes discharge fluids and materials from the subduction channel, they provide a means to characterize thermal, geochemical, and pressure conditions within the seismogenic zone. Previous coring on Ocean Drilling Program (ODP) Legs 125 and 195 at two other serpentinite mud volcanoes (Conical and South Chamorro Seamounts, respectively) and piston, gravity, and push cores from several other Mariana serpentinite mud volcanoes add to this transect of deep-sourced material that is discharged at the seafloor. Pore waters were squeezed from cored serpentinite materials to determine the composition of deep-sourced fluid from the subduction channel and to assess the character, extent, and effect of diagenetic reactions and mixing with seawater on the flanks of three serpentinite seamounts (Yinazao, Fantangisña, and Asùt Tesoro). In addition, two water-sampling temperature probe (WSTP) fluid samples were collected in two of the cased boreholes, each with at least 30 m of screened casing that allowed formation fluids to discharge into the borehole. Here we report shore-based Li, Rb, Cs, Ba, V, Mo, and U measurements of pore waters and one of the WSTP samples. The alkali metals were analyzed to constrain the temperature of reaction in the subduction channel. The other elements were analyzed to assess potential biogenic and diagenetic reactions as the serpentinite material weathers and exchanges with bottom seawater via diffusion. Results were generally consistent with earlier coring and drilling operations, resulting in systematic changes in the composition of the deep-sourced fluid with distance from the trench.
Lang, Susan; Seewald, Jeffrey; McCollom, Thomas
(, Zenodo)
In January – February 2020, RV Atlantis cruise AT42-22 collected water, volatile, and fluid samples with ROV Jason from hydrothermal vent fields on the mid-Cayman rise. The expedition carried out 4 dives at the Von Damm field and 5 at the Piccard field. The first file is the sampling logs and fluid geochemistry from the Hydrothermal Organic Geochemistry (HOG) sampler. It includes sampling locations, depths, heading, volumes, the highest temperature recorded during sampling, the average fluid temperature recorded during sampling, and pH. The second file is the measured geochemistry of the fluids, including concentrations of hydrogen sulfide, dissolved inorganic carbon, formate, phosphate, nitrate, nitrite, ammonia, and the stable isotope composition (d13C) of dissolved inorganic carbon.
Fryer, P.; Wheat, C.G.; Williams, T.
(, Proceedings of the International Ocean Discovery Program)
null
(Ed.)
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 collected gravity, piston, and remotely operated vehicle push cores across the trench-proximal forearc. Three serpentinite mud volcanoes (Yinazao, Fantangisña, and Asùt Tesoro) were chosen at distances 55 to 72 km from the Mariana Trench. Cores were recovered from active sites of eruption on their summit regions and on the flanks where ancient flows are overlain by more recent ones. Recovered materials show the effects of dynamic processes that are active at these sites, bringing a range of materials to the seafloor, including materials from the crust of the Pacific plate, most notably subducted seamounts (even corals). Most of the recovered material consists of serpentinite mud containing lithic clasts, which are derived from the underlying forearc crust and mantle and the subducting Pacific plate. A thin cover of pelagic sediment was recovered at many Expedition 366 sites, and at Site U1498 we cored through distal serpentinite mudflows and into the underlying pelagic sediment and volcanic ash deposits. Recovered serpentinized ultramafic rocks and mudflow matrix materials are largely uniform in major element composition, spanning a limited range in SiO2, MgO, and Fe2O3 compositions. However, variation in trace element composition reflects interstitial water composition, which differs as a function of the temperature and pressure of the underlying subduction channel. Dissolved gases H2, CH4, and C2H6 are highest at the site farthest from the trench, which also has the most active fluid discharge of the Expedition 366 serpentinite mud volcanoes. These dissolved gases and their active discharge from depth likely support active microbial communities, which were the focus of in-depth subsampling and preservation for shore-based analytical and culturing procedures. The effects of fluid discharge were also registered in the porosity and gamma ray attenuation density data indicated by higher than expected values at some of the summit sites. These higher values are consistent with overpressured fluids that slow compaction of serpentinite mud deposits. In contrast, flank sites have significantly greater decreases in porosity with depth, suggesting that processes in addition to compaction are required to achieve the observed data. Thermal measurements reveal higher heat flow values on the flanks (~31 mW/m2) than on the summits (~17 mW/m2) of the seamounts. The new 2G Enterprises superconducting rock magnetometer (liquid helium free) revealed relatively high values of both magnetization and bulk magnetic susceptibility of discrete samples related to ultramafic rocks, particularly dunite. Magnetite, a product of serpentinization, and authigenic carbonates were observed in the mudflow matrix materials. In addition to coring operations, Expedition 366 focused on the deployment and remediation of borehole casings for future observatories and set the framework for in situ experimentation. Borehole work commenced at South Chamorro Seamount, where the original-style CORK was partially removed. Work then continued at each of the three summit sites following coring operations. Cased boreholes with at least three joints of screened casing were deployed, and a plug of cement was placed at the bottom of each hole. Water samples were collected from two of the three boreholes, revealing significant inputs of formation fluids. This suggests that each of the boreholes tapped a hydrologic zone, making these boreholes suitable for experimentation with the future deployment of a CORK-Lite.
Fryer, P.; Wheat, G.; Williams, T.
(, Preliminary report)
null
(Ed.)
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, Fantangisña, and Asùt Tesoro) were chosen at distances 55 to 72 km from the Mariana Trench. Cores were recovered from active sites of eruption on their summit regions and on the flanks where ancient flows are overlain by more recent ones. Recovered materials show the effects of dynamic processes that are active at these sites, bringing a range of materials to the seafloor, including materials from the lithosphere of the Pacific plate and from subducted seamounts (including corals). Most of the recovered material consists of serpentinite mud containing lithic clasts, which are derived from the underlying forearc crust and mantle and the subducting Pacific plate. Cores from each of the three seamounts drilled during Expedition 366, as well as those from Legs 125 and 195, include material from the underlying Pacific plate. A thin cover of pelagic sediment was recovered at many Expedition 366 sites, and at Site U1498 we cored through serpentinite flows to the underlying pelagic sediment and volcanic ash deposits. Recovered serpentinites are largely uniform in major element composition, with serpentinized ultramafic rocks and serpentinite muds spanning a limited range in SiO2 , MgO, and Fe2 O3 compositions. However, variation in trace element composition reflects pore fluid composition, which differs as a function of the temperature and pressure of the underlying subduction channel. Dissolved gases H2 , CH4 , and C2 H6 are highest at the site furthest from the trench, which also has the most active fluid discharge of the Expedition 366 serpentinite mud volcanoes. These dissolved gases and their active discharge from depth likely support active microbial communities, which were the focus of in-depth subsampling and preservation for shore-based analytical and culturing procedures. The effects of fluid discharge were also registered in the porosity and GRA density data indicated by higher than expected values at some of the summit sites. These higher values are consistent with overpressured fluids that minimize compaction of serpentinite mud deposits. In contrast, flank sites have significantly greater decreases in porosity with depth, suggesting that processes in addition to compaction are required to achieve the observed data. Thermal measurements reveal higher heat flow values on the flanks (~31 mW/m2) than on the summits (~17 mW/m2) of the seamounts. The new 2G Enterprises superconducting rock magnetometer (liquid helium free) revealed relatively high values of both magnetization and bulk magnetic susceptibility of discrete samples related to ultramafic rocks, particularly in dunite. Magnetite, a product of serpentinization, and authigenic carbonates were observed in the mudflow matrix materials. In addition to coring operations, Expedition 366 focused on the deployment and remediation of borehole casings for future observatories and set the framework for in situ experimentation. Borehole work commenced at South Chamorro Seamount, where the original-style CORK was partially removed. Work then continued at each of the three summit sites following coring operations. Cased boreholes with at least three joints of screened casing were deployed, and a plug of cement was placed at the bottom of each hole. Water samples were collected from two of the three boreholes, revealing significant inputs of formation fluids. This suggests that each of the boreholes tapped a hydrologic zone, making these boreholes suitable for experimentation with the future deployment of a CORK-lite. An active education and outreach program connected with many classrooms on shore and with the general public through social media.
Fryer, P.; Wheat, C.G.; Williams, T.
(, Scientific prospectus)
null
(Ed.)
International Ocean Discovery Program (IODP) Expedition 366 has two primary science objectives. The first objective is devoted to coring a series of sites at the summit and flanks of three large (up to 50 km diameter and 2 km high) serpentinite mud volcanoes in the Mariana forearc (within 100 km west of the Mariana Trench). This objective addresses the broad scientific aim of examining processes of mass transport within the subduction zone of a nonaccretionary convergent margin. In detail, the plan is to recover mudflow materials to (1) examine processes of mass transport and geochemical cycling within the forearc of a nonaccretionary convergent margin; (2) ascertain the spatial variability of slab-related fluids within the forearc environment as a means of tracing dehydration, decarbonation, and water-rock reactions in subduction and suprasubduction zone environments; (3) study the metamorphic and tectonic history of this nonaccretionary forearc region; (4) investigate the physical properties of the subduction zone in relation to dehydration reactions and seismicity; (5) document microbial activity associated with subduction zone material from great depth; and (6) explore linkages among these subduction-related processes, including seismicity, while placing the effects of these processes within a historical context. The second objective establishes long-term seafloor observatory sites by emplacing cased boreholes at summit (conduit) holes in three mud volcanoes (at Expedition 366 proposed Sites MAF-11A, MAF-9B, and MAF-15A) and removing the circulation obviation retrofit kit (CORK) body from Ocean Drilling Program Hole 1200C. These activities set the foundation for future deployments of sensors and samplers with the possibility of deploying a CORK-Lite structure within the boreholes. CORK-Lites provide a framework for conducting temporal observations that will allow one to “take the pulse of subduction” in an active nonaccretionary convergent plate margin and establish a platform for in situ experimentation.
Lang, Susan, Petersen, Madelyn, Wheat, Charles, and Seewald, Jeffrey. Sample description and geochemistry collected from Mariana forearc boreholes with the HOG sampler. Web. doi:10.5281/zenodo.18022177.
@article{osti_10657774,
place = {Country unknown/Code not available},
title = {Sample description and geochemistry collected from Mariana forearc boreholes with the HOG sampler},
url = {https://par.nsf.gov/biblio/10657774},
DOI = {10.5281/zenodo.18022177},
abstractNote = {{"Abstract":["Sample description and geochemistry collected from Mariana forearc boreholes with the HOG sampler\n\nProject Name:\n\nCollaborative Research: Collaborative Research: Characterization of Subduction Channel Processes, Borehole Sampling at Active Serpentinite Mud Volcanoes on the Mariana\n\nFunding: \n\nNSF-OCE-1921654 Susan Lang, Woods Hole Oceanographic InstitutionForearc\n\nNSF-OCE-1922671 Geoff Wheat, University of Alaska Fairbanks\n\nNSF-OCE-1921361 Jeff Seewald, Woods Hole Oceanographic Institution\n\n \n\nPermits:\n\nMariana Trench National Wildlife Refuge, U.S. Fish & Wildlife Service,\n\nDepartment of the Interior Permit Number: 12541-22009\n\n \n\nProject goals: \n\nThe overarching goal of the project was to understand the reaction processes that occur at depth during subduction. Boreholes drilled during the recent International Ocean Discovery Program Expedition 366 were targeted to collect pristine fluids. \n\n \n\nThe specific goals of the project were to (1) determine the water-rock reactions that control the chemical composition of deep-sourced fluids ascending from atop a subducting slap (2) identify the processes that regulate the nonbiological formation of methane, and assess its potential metabolic impact (3) characterize the origin and abundance of organic carbon molecules to constrain redox and pH conditions within the subduction channel and shallow subsurface environment and (4) relate the permeability of fluid pathways to seamount structure\n\n \n\nSamples were collected during a 25 day expedition with a deep-sea submersible. A CORK-Lite was be deployed at three newly cased boreholes: U1492D (Yinazao), U1497D (Fantangisña), and U1496C (Asùt Tesoru). Fluids discharging from these three new boreholes, and a fourth already cased borehole (U1200C, South Chamorro), were collected for inorganic and organic geochemical analysis.\n\nDataset Description:\n\nTable 1. Sample Logs. Summary of samples collected by the Hydrothermal Organic Geochemistry (HOG) sampler on R/V Kilo Moana (KM22-14) with ROV Jason, on dives J2_1468 through J2_1478, November 20, 2022 to December 17, 2022. Fluid samples were collected into either 2 L or 11 L kynar bags that were acid washed (10% HCl soak overnight, followed by through rinsing, overnight Milli-Q soak, and further rinsing). Additional samples were collected by filtering fluids in situ through sterivex filters, flat filters loaded with RNA later, or copper tubes used for helium gas sampling. Partway through the expedition, a long tube was added to the intake of the sampler that reached deeper into the borehole. Samples collected after this addition recovered higher purity fluids. N.D. is no data.\n\nTable 2. Geochemical Data including pH, alkalinity, hydrolizable amino acids, free amino acids, total acetate, total formate, stable isotopes of dissolved inorganic carbon (δ13C), and stable isotopes of water (δ2H and δ18O)."]}},
journal = {},
publisher = {Zenodo},
author = {Lang, Susan and Petersen, Madelyn and Wheat, Charles and Seewald, Jeffrey},
}
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