THE GEOLOGY OF SEA-FLOOR MASSIVE SULPHIDES
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low impact and the same as or similar to those used in conduct-
ing marine scientific research, such as:
• sidescan sonar;
• multibeam bathymetry;
• electromagnetics;
• three-dimensional plume mapping; and/or
• water-chemistry testing.
Data are collected from ship-mounted sensors and deep-
towed systems, which “fly” close to the sea-floor. From these
data, maps are created at a resolution high enough to select
possible SMS sites. The resolution is rarely good enough to
identify the sulphide structures directly, so a target testing
phase is necessary.
4.1.2 Target testing and prospect delineation
Following target identification, possible SMS deposits are con-
firmed by direct inspection using a remotely operated vehicle (ROV)
and physical sampling of sea-floor rocks. This stage may involve:
Photo of the IMI-30 deep-towed sidescan sonar. The IMI-30 is
a 30 kHz sonar built and operated by the Hawaii Mapping Re-
search Group at the University of Hawaii. It is designed to be
towed from 100 to 500 m above the seafloor and obtain high
resolution sonar images. It can reach depths up to 6000 m. It is
shown being deployed from the R/V Thomas G Thompson in the
southern Mariana back-arc basin area in 2012. Photo courtesy
of Hawaii Mapping Research Group at the University of Hawaii.
The Autonomous Benthic Explorer (ABE) is a robotic underwater
vehicle used for exploring the ocean to depths of 4,500 meters
(14,764 feet). Photo courtesy of WHOI.
Operation of the British Geological Survey seabed drill from the
R/V Sonne. Photo courtesy of S. Petersen, GEOMAR.
Operation of the British Geological Survey seabed drill from the
R/V Sonne. Photo courtesy of S. Petersen, GEOMAR.
