Near-field variability of the TAG non-buoyant plume, 26°N, Mid-Atlantic Ridge

Rudnicki, M.D., James, R.H. and Elderfield, H. (1994) Near-field variability of the TAG non-buoyant plume, 26°N, Mid-Atlantic Ridge. Earth and Planetary Science Letters, 127 (1-4), 1-10. (doi:10.1016/0012-821X(94)90193-7).

Abstract

We report the initial results of a nine hour monitoring of the non-buoyant plume above the TAG hydrothermal vent field at 26°N on the Mid-Atlantic Ridge. A CTD (conductivity, temperature and pressure) and nephelometer (particle sensor) were continuously raised and lowered through the non-buoyant plume for nine hours at a site situated ? 100 m south of the hydrothermal mound. This method permits a detailed record of the variability of the non-buoyant plume close to the vent field to be made. Our results show that the particulate maximum of the non-buoyant plume appears ? 150 m lower in the water column at the start and end of the record, compared with profiles recorded towards the middle of the record. A corresponding structure also appears in the temperature and salinity records, with the result that the plume particle maximum resides on the ?? ? 27.8035 isopycnal throughout. Modelling of the rise height of an axisymmetric plume can only account for ? 95 m of the variability in the final level of neutral buoyancy. Plume bending due to currents is a likely explanation for the recorded temporal variability.

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Contributors

Author: R.H. James

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