May 20, 1993 Journal article Open Access

Dawn J Wright; R. Haymon; Dawn J Wright; Michael Perfit; D. Fornari

JSON-LD (schema.org) Export

{
  "description": "In April, 1991, we witnessed from the submersible Alvin a suite of previously undocumented seafloor phenomena\naccompanying an in-progress eruption of the mid-ocean ridge on the East Pacific Rise crest at 9\u00b045'N-52'N. The volume of\nthe eruption could not be precisely determined, although comparison of pre- and post-eruption SeaBeam bathymetry\nindicate that any changes in ridge crest morphology resulting from the eruption were < 10 m high.\nEffects of the eruption included: (1) increased abundance and redistribution of hydrothermal vents, disappearance of\nnumerous vent communities, and changes in characteristics of vent fauna and mineral deposits within the eruption area\nsince December, 1989; (2) murkiness of bottom waters up to tens of meters above the seafloor due to high densities of\nsuspended mineral and biogenic particulates; (3) destruction of a vent community by lava flows, mass wasting, and possible\nhydrovolcanic explosion at a site known as 'Tubeworm Barbecue' in the axial summit caldera (ASC) at 9\u00b050.6'N; (4)\nnear-critical temperatures of hydrothermal vent fluids, ranging up to 403\u00b0C; (5) temporal variations over a 2 week interval in\nboth temperatures and chemical/isotopic compositions of hydrothermal fluids; (6) unusual compositions of end-member\nvent fluids, with pH values ranging to a record low of 2.5, salinities ranging as low as 0.3 wt% NaCI (one-twelfth that of\nseawater), and dissolved gases reaching high concentrations (> 65 mmol/1 for both CO 2 and H2S); (7) venting at\ntemperatures above 380\u00b0C of visually detectable white vapor that transformed to plumes of gray smoke a few centimeters\nabove vent orifices; (8) disorganized venting of both high-temperature fluids (black and gray smoke) and large volumes of cooler, diffuse hydrothermal fluids directly from the basaltic seafloor, rather than from hydrothermal mineral constructions;\n(9) rapid and extensive growth of flocculent white bacterial mats (species unknown) on and under the seafloor in areas\nexperiencing widespread venting of diffuse hydrothermal fluid; and (10) subseafloor downslope migration of magma normal\nto the ridge axis in a network of small-scale (1-5 m diameter) lava tubes and channels to distances at least 100-200 m\noutside the ASC.\nWe suggest that, in April, 1991, intrusion of dikes in the eruption area to < 200 m beneath the ASC floor resulted in\nphase separation of fluids near the tops of the dikes and a large flux of vapor-rich hydrothermal fluids through the overlying\nrubbly, cavernous lavas. Low salinities and gas-rich compositions of hydrothermal fluids sampled in the eruption area are\nappropriate for a vapor phase in a seawater system undergoing subcritical liquid-vapor phase separation (boiling) and phase\nsegregation. Hydrothermal fluids streamed directly from fissures and pits that may have been loci of lava drainback and/or\nhydrovolcanic explosions. These fissures and pits were lined with white mats of a unique fast-growing bacteria that was the\nonly life associated with the brand-new vents. The prolific bacteria, which covered thousands of square meters on the ridge\ncrest and were also abundant in subseafloor voids, may thrive on high levels of gases in the vapor-rich hydrothermal fluids\ninitially escaping the hydrothermal system. White bacterial particulates swept from the seafloor by hydrothermal vents\nswirled in an unprecedented biogenic 'blizzard' up to 50 m above the bottom. The bacterial proliferation of April, 1991 is\nlikely to be a transient bloom that will be checked quickly either by decline of dissolved gas concentrations in the fluids as\nrapid heat loss brings about cessation of boiling, and/or by grazing as other organisms are re-established in the biologically\ndevastated area.", 
  "license": "https://creativecommons.org/licenses/by/4.0/legalcode", 
  "creator": [
    {
      "affiliation": "Environmental Systems Research Institute", 
      "@type": "Person", 
      "name": "Dawn J Wright"
    }, 
    {
      "affiliation": "UCSB", 
      "@type": "Person", 
      "name": "R. Haymon"
    }, 
    {
      "affiliation": "Environmental Systems Research Institute", 
      "@type": "Person", 
      "name": "Dawn J Wright"
    }, 
    {
      "affiliation": "University of Florida", 
      "@type": "Person", 
      "name": "Michael Perfit"
    }, 
    {
      "affiliation": "WHOI", 
      "@type": "Person", 
      "name": "D. Fornari"
    }
  ], 
  "headline": "Volcanic eruption of the mid-ocean ridge along the East Pacific Rise crest at 9\u00b045\u201352\u2032N: Direct submersible observations of seafloor phenomena associated with an eruption event in April, 1991", 
  "image": "https://zenodo.org/static/img/logos/zenodo-gradient-round.svg", 
  "datePublished": "1993-05-20", 
  "url": "https://zenodo.org/record/268748", 
  "keywords": [
    "Earth Sciences", 
    "Mid Ocean Ridge", 
    "Physical sciences", 
    "High Temperature", 
    "Earth and Planetary Science", 
    "Hydrothermal Vent", 
    "Phase Separation", 
    "High Density Concrete", 
    "Volcanic Eruption", 
    "Critical Temperature", 
    "Heat Loss"
  ], 
  "@context": "https://schema.org/", 
  "identifier": "https://doi.org/10.5281/zenodo.268748", 
  "@id": "https://doi.org/10.5281/zenodo.268748", 
  "@type": "ScholarlyArticle", 
  "name": "Volcanic eruption of the mid-ocean ridge along the East Pacific Rise crest at 9\u00b045\u201352\u2032N: Direct submersible observations of seafloor phenomena associated with an eruption event in April, 1991"
}