114
The Last Resource
some of these metals appear to be accumulating faster than they
could at present be used. And, these manganese nodules are not
restricted to the Pacic—they are also found in the Atlantic and
Indian Oceans. They were rst dredged from Scottish lochs.
As if these gures were not impressive enough, other even more
extensive mineral deposits are found on the deep ocean oor.
Calcareous and siliceous oozes and red clays are by far the most
abundant sediments, (days hold less than 30 per cent organic
remains and oozes contain more than 30 per cent of these animal or
plant eñluvia). There are some ten thousand million million tons of
calcareous oozes lying over some 128 million square kilometres.
This ooze, which lies at depths up to about two and a half miles,
consists largely of the skeletons of planktonic animals called
Foraminifera (mainly the species Globigerina bullaz'des). These
microscopic animals have coiled shells not unlike those of a snail
except that instead of a single foot they have long lamentous
processes which extend from the sieve—like walls of the shell. If the
ooze were mined, it would provide su‘icient calcium carbonate for
literally millions of years. The siliceous oozes also come from
organisms in the plankton but in this instance both animals, such as
the radiolaria, and plants, such as the capsules of diatoms, contribute
to them. The remains of diatoms which lived in prehistoric seas are
already mined and used to make ceramics and linings for furnaces.
Finally, the red clay, which also occurs in the deeper waters, may
contain signicant amounts of metals such as copper and aluminium
as well as several of the rare earth elements. This red clay is all that
remains after the calcium carbonate and less resistant substances
have been leached out, but deposits of it probably equal the cal—
careous oozes in total quantity.
ln spite of their abundance, neither red clay nor calcareous and
siliceous oozes are being considered for exploitation; manganese
nodules are claimed to be the ocean’s nuggets, although the
average depth at which they are found—about 13,000 feet in the
Pacic—makes conventional dredging out of the question. Dr Mero
suggests that giant dredges controlled from the surface could sweep
up the nodules from the ocean oor. According to his calculations,
these machines would cost some ,Ç2 million or more and the pro—
cessing equipment would cost perhaps ve times this. Undeterred
by such costs, Dr Mero claims that a prot of around £7 a ton
should be possible and that most of the industrially important
The Last Resource
some of these metals appear to be accumulating faster than they
could at present be used. And, these manganese nodules are not
restricted to the Pacic—they are also found in the Atlantic and
Indian Oceans. They were rst dredged from Scottish lochs.
As if these gures were not impressive enough, other even more
extensive mineral deposits are found on the deep ocean oor.
Calcareous and siliceous oozes and red clays are by far the most
abundant sediments, (days hold less than 30 per cent organic
remains and oozes contain more than 30 per cent of these animal or
plant eñluvia). There are some ten thousand million million tons of
calcareous oozes lying over some 128 million square kilometres.
This ooze, which lies at depths up to about two and a half miles,
consists largely of the skeletons of planktonic animals called
Foraminifera (mainly the species Globigerina bullaz'des). These
microscopic animals have coiled shells not unlike those of a snail
except that instead of a single foot they have long lamentous
processes which extend from the sieve—like walls of the shell. If the
ooze were mined, it would provide su‘icient calcium carbonate for
literally millions of years. The siliceous oozes also come from
organisms in the plankton but in this instance both animals, such as
the radiolaria, and plants, such as the capsules of diatoms, contribute
to them. The remains of diatoms which lived in prehistoric seas are
already mined and used to make ceramics and linings for furnaces.
Finally, the red clay, which also occurs in the deeper waters, may
contain signicant amounts of metals such as copper and aluminium
as well as several of the rare earth elements. This red clay is all that
remains after the calcium carbonate and less resistant substances
have been leached out, but deposits of it probably equal the cal—
careous oozes in total quantity.
ln spite of their abundance, neither red clay nor calcareous and
siliceous oozes are being considered for exploitation; manganese
nodules are claimed to be the ocean’s nuggets, although the
average depth at which they are found—about 13,000 feet in the
Pacic—makes conventional dredging out of the question. Dr Mero
suggests that giant dredges controlled from the surface could sweep
up the nodules from the ocean oor. According to his calculations,
these machines would cost some ,Ç2 million or more and the pro—
cessing equipment would cost perhaps ve times this. Undeterred
by such costs, Dr Mero claims that a prot of around £7 a ton
should be possible and that most of the industrially important