Variations in water-column He/heat ratios associated with the 1993 CoAxial event, Juan de Fuca Ridge

来自 EBSCO

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作者：

J.，E.，Lupton，E.，T.，Baker，G.，J.，Massoth，R.

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摘要：

The 1993 volcanic/hydrothermal event on the CoAxial segment, northern Juan de Fuca Ridge, generated a complex set of event plumes and steady‐state type plumes with a pattern of He/heat ratios very similar to that observed during the 1986 megaplume event on the southern JdFR. The event plumes residing 600 m above the seafloor had "normal" He/heat ratios averaging 0.34 × 1012 cmSTP cal1, while the deeper, steady‐state plumes had elevated He/heat values ranging from 0.6 to 4.5 × 1012 cmSTP cal1. These results generally confirm that elevated He/heat ratios in some of the water‐column plumes are a reliable indicator of a recent magmatic/tectonic event. However, in contrast to the 1986 JdFR event, there was no evidence for hydrothermal activity on the CoAxial segment prior to 1993, thereby requiring revision of our models for event plume generation.

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关键词：

Theoretical or Mathematical, Experimental/ geology helium isotope relative abundance oceanographic regions seafloor phenomena terrestrial heat/ heat temperature chemical composition isotope ratio 3He ocean North Pacific hydrothermal vent plume AD 1993 volcanic eruption model East Pacific Rise water-column CoAxial event Juan de Fuca Ridge steady-state plumes event plume generation He/ A9150E Seafloor processes A9220C Chemistry of the oceans A9330P Pacific Ocean A9210M Thermohaline structure and circulation of the oceans A9135L Geochemistry A9135D Terrestrial heat/ He/el