Hydrothermal event plumes from the coaxial seafloor eruption site, Juan de Fuca Ridge

Abstract

The episodic magmatic intrusions that accompany seafloor spreading can profoundly affect the discharge of hydrothermal heat and fluid. A rapid field response to the acoustic detection of seismic activity on the CoAxial segment of the Juan de Fuca Ridge, June/July 1993, provided the opportunity to conduct a unique series of observations of hydrothermal event plumes. Between July 3 and 26 we detected at least three event plumes ranging in plume volume from 1.3 to 4 × 1010 m³, and in excess heat from 2.2 to 12.4 × 1015 J. Two were discovered directly above a new lava extrusion. One of these was first sampled within days of its release, as evidenced by its asymmetric shape, complex structure, and a steadily increasing light attenuation anomaly apparently generated by ongoing precipitation of hydrothermal Fe. We hypothesize that event plumes were produced intermittently in response to successive volcano‐tectonic events that produced pulses in seismic activity between June 28 and July 14.

Production of CO2 and H2 by Diking-Eruptive Events at Mid-Ocean Ridges: Implications for Abiotic Organic Synthesis and Global Geochemical Cycling

“…A flow with a volume of 5 x 10 6 m 3 was associated with a 40 km long dike that propagated over a two-day period (Baker et al, 1995). Cherkaoui et al (1997) used data from studies of the water column above the dike and concluded that the dike lost most of its heat within three months of intrusion into permeable rock that was saturated with seawater.…”

Generation of hydrothermal megaplumes by cooling of pillow basalts at mid-ocean ridges

“…They concluded that the megaplumes formed over 2±20 d from a ®ssure 2,000±200 m long. Subsequently, additional detached megaplumes have been identi®ed in the North Fiji basin 9 , the Eastern Manus basin 10 and further north on the Juan de Fuca ridge 11 .…”

Thermal fluxes associated with the 1993 diking event on the CoAxial segment, Juan de Fuca Ridge: A model for the convective cooling of a dike

“…0148-0227/97/97JB-02123509.00 The CoAxial event of June 1993 is the first diking event to be detected remotely and monitored by the SOSUS hydrophone arrays ; it is also the first submarine diking event for which seafloor observations are correlated with measurements in the hydrothermal plumes [Baker et al, 1995a] and with seismic data which constrain the temporal and spatial characteristics of dike emplacement [Fox et Along with the seafloor observations, extensive water column measurements were obtained during the initial field response Baker et al, 1995a]. Temperature and light attenuation anomalies were mapped along the segment axis using a conductivity-temperature-depth (CTD) and transmissometer package which was cycled vertically while being towed through the water.…”