Minerals Report - International Seabed Authority

Figure 1: A high-temperature “black smoker” hydrothermal vent emitting super-heated vent
fluid at approximately 350°C from the floor of the Mid-Atlantic Ridge.
Individual high temperature vents at mid-ocean ridges may only be
~10cm in diameter at their mouth, yet over time, growing like stalagmites
from the sea floor, they can form chimneys anywhere from 1m to 30m tall. A
typical vent-field might comprise several such chimney structures spread out
over an area ~100m across. Throughout this area, there may also be a number
of lower temperature vents emitting hot shimmering water from the seabed.
Even these vents are as hot as 10-30°C that is notably warmer than typical
deep ocean water (2-3°C). It is near these warm and more diffuse emissions
that the majority of vent-specific biota is most abundant.
3. The Global Distribution of Seafloor Hydrothermal Venting
3.1 The influence of spreading rate for seafloor hydrothermal venting
Although the global mid-ocean ridge extends as a near-continuous
60,000km volcanic chain that girdles the entire planet (Fig.2), it does not
exhibit the same activity everywhere.
INTERNATIONAL SEABED AUTHORITY 379