Types of Vents:
Column and Black-Smoker Chimneys
Column chimneys are created in the early formation of vent-sites, after volcanic activity. They are common in the Eastern-Pacific. Deposits of sulphide accumulate on the deep sea floor around spreading zones and form chimneys. Upwelling of molten-rock (magma) heats up the surrounding sea-water and supplies the vicinity with sulphur and other minerals (Fig.4) (Haymon & Koski 1985; Lutz & Haymon 1994; Van Dover 2000).
Black-Smokers form when high-temperature, acidic-metal sulphides mix with cool, alkaline salt water form precipitated minerals (metal sulphides) that make up the chimney structures. They emit very hot, mineral-rich, blackened plumes (Stafford 2006; Tait & Dipper 1998; Van Dover 2000).
White-smoker chimneys emit plumes of fluid at temperatures ranging from 100°C to 300°C. Unlike Black-Smokers, White-Smokers do not emit fluids which are at high temperatures that may accommodate metals and sulphides in more significant concentrations; they therefore do not produce plumes that appear black as they mix with the cooler surrounding salt-water (Van Dover 2000).
Figure 4. Alvin – 3.7m in height (McCliment 2004) compared to the 45 metre tall mound of sulphide. This hydrothermal vent is known as ‘Godzilla’ and is situated in the north-east-Pacific, on the Juan de Fuca Ridge (Robigou et al. 1993).
These sulphide-chimneys host an area suitable for the exploitation of an array of fauna, due to select zones of warm water flows over a range of temperatures and fluxes (Van Dover 2000).