Barreyre Thibaut

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Barreyre

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Thibaut

ORCID

0000-0002-5109-2633

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Hydrothermal activity along the slow-spreading Lucky Strike ridge segment (Mid-Atlantic Ridge) : distribution, heatflux, and geological controls

( 2015-09) Escartin, Javier E. ; Barreyre, Thibaut ; Cannat, Mathilde ; Garcia, Rafael ; Gracias, Nuno ; Deschamps, Anne ; Salocchi, Aura ; Sarradin, Pierre-Marie ; Ballu, Valerie

We have reviewed available visual information from the seafloor, and recently acquired microbathymetry for several traverses across the Lucky Strike segment, to evaluate the distribution of hydrothermal activity. We have identified a new on-axis site with diffuse flow, Ewan, and anactive vent structure ~1.2 km from the axis, Capelinhos. These sites are minor relative to the Main field, and our total heatflux estimate for all active sites (200-1200 MW) is only slightly higher than previously published estimates. We also identify fossil sites W of the main Lucky Strike field. A circular feature ~200 m in diameter located on the flanks of a rifted off-axis central volcano, is likely a large and inactive hydrothermal edifice, named Grunnus. We find no indicator of focused hydrothermal activity elsewhere along the segment, suggesting that the enhanced melt supply and the associated melt lenses, required to form central volcanoes, also sustain hydrothermal circulation to form and maintain large and long-lived hydrothermal fields. Hydrothermal discharge to the seafloor occurs along fault traces, suggesting focusing of hydrothermal circulation in the shallow crust along permeable fault zones.
Quantifying diffuse and discrete venting at the Tour Eiffel vent site, Lucky Strike hydrothermal field

(American Geophysical Union, 2012-04-19) Mittelstaedt, Eric ; Escartin, Javier E. ; Gracias, Nuno ; Olive, Jean-Arthur L. ; Barreyre, Thibaut ; Davaille, Anne ; Cannat, Mathilde ; Garcia, Rafael

The relative heat carried by diffuse versus discrete venting of hydrothermal fluids at mid-ocean ridges is poorly constrained and likely varies among vent sites. Estimates of the proportion of heat carried by diffuse flow range from 0% to 100% of the total axial heat flux. Here, we present an approach that integrates imagery, video, and temperature measurements to accurately estimate this partitioning at a single vent site, Tour Eiffel in the Lucky Strike hydrothermal field along the Mid-Atlantic Ridge. Fluid temperatures, photographic mosaics of the vent site, and video sequences of fluid flow were acquired during the Bathyluck'09 cruise (Fall, 2009) and the Momarsat'10 cruise (Summer, 2010) to the Lucky Strike hydrothermal field by the ROV Victor6000 aboard the French research vessel the “Pourquoi Pas”? (IFREMER, France). We use two optical methods to calculate the velocities of imaged hydrothermal fluids: (1) for diffuse venting, Diffuse Flow Velocimetry tracks the displacement of refractive index anomalies through time, and (2) for discrete jets, Particle Image Velocimetry tracks eddies by cross-correlation of pixel intensities between subsequent images. To circumvent video blurring associated with rapid velocities at vent orifices, exit velocities at discrete vents are calculated from the best fit of the observed velocity field to a model of a steady state turbulent plume where we vary the model vent radius and fluid exit velocity. Our results yield vertical velocities of diffuse effluent between 0.9 cm s−1 and 11.1 cm s−1 for fluid temperatures between 3°C and 33.5°C above that of ambient seawater, and exit velocities of discrete jets between 22 cm s−1 and 119 cm s−1 for fluid temperatures between 200°C and 301°C above ambient seawater. Using the calculated fluid velocities, temperature measurements, and photo mosaics of the actively venting areas, we calculate a heat flux due to diffuse venting from thin fractures of 3.15 ± 2.22 MW, discrete venting of 1.07 ± 0.66 MW, and, by incorporating previous estimates of diffuse heat flux density from Tour Eiffel, diffuse flux from the main sulfide mound of ∼15.6 MW. We estimate that the total integrated heat flux from the Tour Eiffel site is 19.82 ± 2.88 MW and that the ratio of diffuse to discrete heat flux is ∼18. We discuss the implication of these results for the characterization of different vent sites within Lucky Strike and in the context of a compilation of all available measurements of the ratio of diffuse to discrete heat flux.
Discovery of active off-axis hydrothermal vents at 9° 54’N East Pacific Rise

(National Academy of Sciences, 2022-07-21) McDermott, Jill M. ; Parnell-Turner, Ross ; Barreyre, Thibaut ; Herrera, Santiago ; Downing, Connor C. ; Pittoors, Nicole C. ; Pehr, Kelden ; Vohsen, Samuel A. ; Dowd, William S. ; Wu, Jyun-Nai ; Marjanovic, Milena ; Fornari, Daniel J.

Comprehensive knowledge of the distribution of active hydrothermal vent fields along midocean ridges is essential to understanding global chemical and heat fluxes and endemic faunal distributions. However, current knowledge is biased by a historical preference for on-axis surveys. A scarcity of high-resolution bathymetric surveys in off-axis regions limits vent identification, which implies that the number of vents may be underestimated. Here, we present the discovery of an active, high-temperature, off-axis hydrothermal field on a fast-spreading ridge. The vent field is located 750 m east of the East Pacific Rise axis and ∼7 km north of on-axis vents at 9° 50′N, which are situated in a 50- to 100-m-wide trough. This site is currently the largest vent field known on the East Pacific Rise between 9 and 10° N. Its proximity to a normal fault suggests that hydrothermal fluid pathways are tectonically controlled. Geochemical evidence reveals deep fluid circulation to depths only 160 m above the axial magma lens. Relative to on-axis vents at 9° 50′N, these off-axis fluids attain higher temperatures and pressures. This tectonically controlled vent field may therefore exhibit greater stability in fluid composition, in contrast to more dynamic, dike-controlled, on-axis vents. The location of this site indicates that high-temperature convective circulation cells extend to greater distances off axis than previously realized. Thorough high-resolution mapping is necessary to understand the distribution, frequency, and physical controls on active off-axis vent fields so that their contribution to global heat and chemical fluxes and role in metacommunity dynamics can be determined.
Depth‐dependent permeability and heat output at basalt‐hosted hydrothermal systems across mid‐ocean ridge spreading rates

(John Wiley & Sons, 2018-04-20) Barreyre, Thibaut ; Olive, Jean-Arthur ; Crone, Timothy J. ; Sohn, Robert A.

The permeability of the oceanic crust exerts a primary influence on the vigor of hydrothermal circulation at mid‐ocean ridges, but it is a difficult to measure parameter that varies with time, space, and geological setting. Here we develop an analytical model for the poroelastic response of hydrothermal exit‐fluid velocities and temperatures to ocean tidal loading in a two‐layered medium to constrain the discharge zone permeability of each layer. The top layer, corresponding to extrusive lithologies (e.g., seismic layer 2A) overlies a lower permeability layer, corresponding to intrusive lithologies (e.g., layer 2B). We apply the model to three basalt‐hosted hydrothermal fields (i.e., Lucky Strike, Main Endeavour and 9°46′N L‐vent) for which the seismic stratigraphy is well‐established, and for which robust exit‐fluid temperature data are available. We find that the poroelastic response to tidal loading is primarily controlled by layer 2A permeability, which is about 3 orders of magnitude higher for the Lucky Strike site (∼10−10 m2) than the 9°46′N L‐vent site (∼10−13 m2). By contrast, layer 2B permeability does not exert a strong control on the poroelastic response to tidal loading, yet strongly modulates the heat output of hydrothermal discharge zones. Taking these constraints into account, we estimate a plausible range of layer 2B permeability between ∼10−15 m2 and an upper‐bound value of ∼10−14 (9°46′N L‐vent) to ∼10−12 m2 (Lucky Strike). These permeability structures reconcile the short‐term response and long‐term thermal output of hydrothermal sites, and provide new insights into the links between permeability and tectono‐magmatic processes along the global mid‐ocean ridge.
Structure, temporal evolution, and heat flux estimates from the Lucky Strike deep-sea hydrothermal field derived from seafloor image mosaics

(American Geophysical Union, 2012-04-19) Barreyre, Thibaut ; Escartin, Javier E. ; Garcia, Rafael ; Cannat, Mathilde ; Mittelstaedt, Eric ; Prados, Ricard

Here we demonstrate with a study of the Lucky Strike hydrothermal field that image mosaicing over large seafloor areas is feasible with new image processing techniques, and that repeated surveys allow temporal studies of active processes. Lucky Strike mosaics, generated from >56,000 images acquired in 1996, 2006, 2008 and 2009, reveal the distribution and types of diffuse outflow throughout the field, and their association with high-temperature vents. In detail, the zones of outflow are largely controlled by faults, and we suggest that the spatial clustering of active zones likely reflects the geometry of the underlying plumbing system. Imagery also provides constraints on temporal variability at two time-scales. First, based upon changes in individual outflow features identified in mosaics acquired in different years, we document a general decline of diffuse outflow throughout the vent field over time-scales up to 13 years. Second, the image mosaics reveal broad patches of seafloor that we interpret as fossil outflow zones, owing to their association with extinct chimneys and hydrothermal deposits. These areas encompass the entire region of present-day hydrothermal activity, suggesting that the plumbing system has persisted over long periods of time, loosely constrained to hundreds to thousands of years. The coupling of mosaic interpretation and available field measurements allow us to independently estimate the heat flux of the Lucky Strike system at ~200 to 1000 MW, with 75% to >90% of this flux taken up by diffuse hydrothermal outflow. Based on these heat flux estimates, we propose that the temporal decline of the system at short and long time scales may be explained by the progressive cooling of the AMC, without replenishment. The results at Lucky Strike demonstrate that repeated image surveys can be routinely performed to characterize and study the temporal variability of a broad range of vent sites hosting active processes (e.g., cold seeps, hydrothermal fields, gas outflows, etc.), allowing a better understanding of fluid flow dynamics from the sub-seafloor, and a quantification of fluxes.
Extent and volume of lava flows erupted at 9°50’N, East Pacific Rise in 2005–2006 from autonomous underwater vehicle surveys

(American Geophysical Union, 2022-01-28) Wu, Jyun-Nai ; Parnell-Turner, Ross ; Fornari, Daniel J. ; Kurras, Gregory ; Berrios-Rivera, Natalia ; Barreyre, Thibaut ; McDermott, Jill M.

Seafloor volcanic eruptions are difficult to directly observe due to lengthy eruption cycles and the remote location of mid-ocean ridges. Volcanic eruptions in 2005–2006 at 9°50′N on the East Pacific Rise have been well documented, but the lava volume and flow extent remain uncertain because of the limited near-bottom bathymetric data. We present near-bottom data collected during 19 autonomous underwater vehicle (AUV) Sentry dives at 9°50′N in 2018, 2019, and 2021. The resulting 1 m-resolution bathymetric grid and 20 cm-resolution sidescan sonar images cover 115 km2, and span the entire area of the 2005–2006 eruptions, including an 8 km2 pre-eruption survey collected with AUV ABE in 2001. Pre- and post-eruption surveys, combined with sidescan sonar images and seismo-acoustic impulsive events recorded during the eruptions, are used to quantify the lava flow extent and to estimate changes in seafloor depth caused by lava emplacement. During the 2005–2006 eruptions, lava flowed up to ∼3 km away from the axial summit trough, covering an area of ∼20.8 km2; ∼50% larger than previously thought. Where pre- and post-eruption surveys overlap, individual flow lobes can be resolved, confirming that lava thickness varies from ∼1 to 10 m, and increases with distance from eruptive fissures. The resulting lava volume estimate indicates that ∼57% of the melt extracted from the axial melt lens probably remained in the subsurface as dikes. These observations provide insights into recharge cycles in the subsurface magma system, and are a baseline for studying future eruptions at the 9°50′N area.
Temporal variability and tidal modulation of hydrothermal exit-fluid temperatures at the Lucky Strike deep-sea vent field, Mid-Atlantic Ridge

(John Wiley & Sons, 2014-04-02) Barreyre, Thibaut ; Escartin, Javier E. ; Sohn, Robert A. ; Cannat, Mathilde ; Ballu, Valerie ; Crawford, Wayne C.

We deployed autonomous temperature sensors at black smoker chimneys, cracks, and diffuse flow areas at the Lucky Strike hydrothermal field (Mid-Atlantic Ridge, ~37°17'N) between summer 2009 and summer 2012 and contemporaneously measured tidal pressures and currents as part of the long-term MoMAR experiment to monitor hydrothermal activity. We classify the temperature data according to the hydrogeologic setting of the measurement sites: a high-temperature regime (>190°C) representing discharge of essentially unmixed, primary hydrothermal fluids through chimneys, an intermediate-temperature regime (10–100°C) associated with mixing of primary fluids with cold pore fluids discharging through cracks, and a low-temperature regime (<10°C) associated with a thermal boundary layer forming over bacterial mats associated with diffuse outflow of warm fluids. Temperature records from all the regimes exhibit variations at semi-diurnal tidal periods, and cross-spectral analyses reveal that high-temperature discharge correlates to tidal pressure while low-temperature discharge correlates to tidal currents. Intermediate-temperature discharge exhibits a transitional behavior correlating to both tidal pressure and currents. Episodic perturbations, with transient temperature drops of up to ~150°C, which occur in the high-temperature and intermediate-temperature records, are not observed on multiple probes (including nearby probes at the same site), and they are not correlated with microearthquake activity, indicating that the perturbation mechanism is highly localized at the measurement sites within the hydrothermal structures. The average temperature at a given site may increase or decrease at annual time scales, but the average temperature of the hydrothermal field, as a whole, appears to be stable over our 3 year observation period.
Tracking crustal permeability and hydrothermal response during seafloor eruptions at the East Pacific Rise, 9°50’N

(American Geophysical Union, 2022-01-24) Barreyre, Thibaut ; Parnell-Turner, Ross ; Wu, Jyun-Nai ; Fornari, Daniel J.

Permeability controls energy and matter fluxes in deep-sea hydrothermal systems fueling a 'deep biosphere' of microorganisms. Here, we indirectly measure changes in sub-seafloor crustal permeability, based on the tidal response of high-temperature hydrothermal vents at the East Pacific Rise 9°50’N preceding the last phase of volcanic eruptions during 2005–2006. Ten months before the last phase of the eruptions, permeability decreased, first rapidly, and then steadily as the stress built up, until hydrothermal flow stopped altogether ∼2 weeks prior to the January 2006 eruption phase. This trend was interrupted by abrupt permeability increases, attributable to dike injection during last phase of the eruptions, which released crustal stress, allowing hydrothermal flow to resume. These observations and models suggest that abrupt changes in crustal permeability caused by magmatic intrusion and volcanic eruption can control first-order hydrothermal circulation processes. This methodology has the potential to aid eruption forecasting along the global mid-ocean ridge network.
Poroelastic response of mid-ocean ridge hydrothermal systems to ocean tidal loading : implications for shallow permeability structure

(John Wiley & Sons, 2016-02-26) Barreyre, Thibaut ; Sohn, Robert A.

We use the time delay between tidal loading and exit-fluid temperature response for hydrothermal vents to model the poroelastic behavior and shallow upflow zone (SUZ) effective permeability structure of three mid-ocean ridge (MOR) sites with different spreading rates. Hydrothermal vents at Lucky Strike field exhibit relatively small phase lags corresponding to high SUZ effective permeabilities of ≥ ~10−10 m2, with variations that we interpret as resulting from differences in the extrusive layer thickness. By contrast, vents at East Pacific Rise site exhibit relatively large phase lags corresponding to low SUZ effective permeabilities of ≤ ~10−13 m2. Vents at Main Endeavour field exhibit both high and low phase lags, suggestive of a transitional behavior. Our results demonstrate that tidal forcing perturbs hydrothermal flow across the global MOR system, even in places where the tidal amplitude is very low, and that the flow response can be used to constrain variations in SUZ permeability structure beneath individual vent fields.
Integrating Multidisciplinary Observations in Vent Environments (IMOVE): decadal progress in deep-sea observatories at hydrothermal vents

(Frontiers Media, 2022-05-13) Matabos, Marjolaine ; Barreyre, Thibaut ; Juniper, S. Kim ; Cannat, Mathilde ; Kelley, Deborah S. ; Alfaro-Lucas, Joan M. ; Chavagnac, Valerie ; Colaço, Ana ; Escartin, Javier E. ; Escobar Briones, Elva ; Fornari, Daniel J. ; Hasenclever, Jörg ; Huber, Julie A. ; Laës-Huon, Agathe ; Lantéri, Nadine ; Levin, Lisa A. ; Mihaly, Steven F. ; Mittelstaedt, Eric ; Pradillon, Florence ; Sarradin, Pierre-Marie ; Sarradin, Pierre-Marie ; Sarrazin, Jozée ; Tomasi, Beatrice ; Venkatesan, Ramasamy ; Vic, Clément

The unique ecosystems and biodiversity associated with mid-ocean ridge (MOR) hydrothermal vent systems contrast sharply with surrounding deep-sea habitats, however both may be increasingly threatened by anthropogenic activity (e.g., mining activities at massive sulphide deposits). Climate change can alter the deep-sea through increased bottom temperatures, loss of oxygen, and modifications to deep water circulation. Despite the potential of these profound impacts, the mechanisms enabling these systems and their ecosystems to persist, function and respond to oceanic, crustal, and anthropogenic forces remain poorly understood. This is due primarily to technological challenges and difficulties in accessing, observing and monitoring the deep-sea. In this context, the development of deep-sea observatories in the 2000s focused on understanding the coupling between sub-surface flow and oceanic and crustal conditions, and how they influence biological processes. Deep-sea observatories provide long-term, multidisciplinary time-series data comprising repeated observations and sampling at temporal resolutions from seconds to decades, through a combination of cabled, wireless, remotely controlled, and autonomous measurement systems. The three existing vent observatories are located on the Juan de Fuca and Mid-Atlantic Ridges (Ocean Observing Initiative, Ocean Networks Canada and the European Multidisciplinary Seafloor and water column Observatory). These observatories promote stewardship by defining effective environmental monitoring including characterizing biological and environmental baseline states, discriminating changes from natural variations versus those from anthropogenic activities, and assessing degradation, resilience and recovery after disturbance. This highlights the potential of observatories as valuable tools for environmental impact assessment (EIA) in the context of climate change and other anthropogenic activities, primarily ocean mining. This paper provides a synthesis on scientific advancements enabled by the three observatories this last decade, and recommendations to support future studies through international collaboration and coordination. The proposed recommendations include: i) establishing common global scientific questions and identification of Essential Ocean Variables (EOVs) specific to MORs, ii) guidance towards the effective use of observatories to support and inform policies that can impact society, iii) strategies for observatory infrastructure development that will help standardize sensors, data formats and capabilities, and iv) future technology needs and common sampling approaches to answer today’s most urgent and timely questions.
The role of on‐ and off‐axis faults and fissures during eruption cycles and crustal accretion at 9°50′N, East Pacific Rise

(American Geophysical Union, 2023-04-19) Wu, Jyun‐Nai ; Parnell‐Turner, Ross ; Fornari, Daniel J. ; Berrios‐Rivera, Natalia ; Barreyre, Thibaut ; McDermott, Jill M.

Fissures and faults provide insight into how plate separation is accommodated by magmatism and brittle deformation during crustal accretion. Although fissure and fault geometry can be used to quantify the spreading process at mid‐ocean ridges, accurate measurements are rare due to insufficiently detailed mapping data. Here, fissures and faults at the fast‐spreading 9°50′N segment of the East Pacific Rise were mapped using bathymetric data collected at 1‐m horizontal resolution by autonomous underwater vehicle Sentry. Fault dip estimates from the bathymetric data were calibrated using co‐registered near‐bottom imagery and depth transects acquired by remotely operated vehicle Jason. Fissures are classified as either eruptive or non‐eruptive (i.e., cracks). Tectonic strain estimated from corrected fault heaves suggests that faulting plays a negligible role in the plate separation on crust younger than 72 kyr (<4 km from the ridge axis). Pre‐ and post‐eruption surveys show that most fissures were reactivated during the eruptions in 2005–2006. Variable eruptive fissure geometry could be explained by the frequency with which each fissure is reactivated and partially infilled. Fissure swarms and lava plateaus in low‐relief areas >2 km from the ridge are spatially associated with off‐axis lower‐crustal magma lenses identified in multichannel seismic data. Deep, closely spaced fissures overlie a relatively shallow portion of the axial magma lens. The width of on‐axis fissures and inferred subsurface dike geometry imply a ∼9‐year long diking recurrence interval to fully accommodate plate spreading, which is broadly consistent with cycle intervals obtained from estimates of melt extraction rates, eruption volumes, and spreading rate.
Significance of short‐wavelength magnetic anomaly low along the East Pacific Rise axis, 9°50′N

(American Geophysical Union, 2023-05-16) Berrios‐Rivera, Natalia ; Gee, Jeffrey S. ; Parnell‐Turner, Ross ; Maher, Sarah ; Wu, Jyun‐Nai ; Fornari, Daniel ; Tivey, Maurice ; Marjanović, Milena ; Barreyre, Thibaut ; McDermott, Jill

Magnetic anomaly variations near mid‐ocean ridge spreading centers are sensitive to a variety of crustal accretionary processes as well as geomagnetic field variations when the crust forms. We collected near‐bottom vector magnetic anomaly data during a series of 21 autonomous underwater vehicle Sentry dives near 9°50′N on the East Pacific Rise (EPR) covering ∼26 km along‐axis. These data document the 2–3 km wide axial anomaly high that is commonly observed at fast‐spreading ridges but also reveal the presence of a superimposed ∼800 m full wavelength anomaly low. The anomaly low is continuous for ≥13 km along axis and may extend over the entire survey region. A more detailed survey of hydrothermal vents near 9°50.3′N reveals ∼100 m diameter magnetic lows, which are misaligned relative to active vents and therefore cannot explain the continuous axial low. The axial magnetization low persists in magnetic inversions with variable extrusive source thickness, indicating that to the extent to which layer 2A constitutes the sole magnetic source, variations in its thickness alone cannot account for the axial low. Lava accumulation models illustrate that high geomagnetic intensity over the past ∼2.5 kyr, and decreasing intensity over the past ∼900 years, are both consistent with the broad axial anomaly high and the superimposed shorter wavelength low. The continuity of this axial low, and similar features elsewhere on the EPR suggests, that either crustal accretionary processes responsible for this anomaly are common among fast‐spread ridges, or that the observed magnetization low may partially reflect global geomagnetic intensity fluctuations.

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