102
The Last Resource
Large companies are slowly moving towards the idea of exploiting
the oceans, some are already searching for new mineral deposits,
but no matter how strong the current emotional sway towards this
neglected resource, the number of commercial marine activities are
likely to remain restricted to a few paying propositions for some
years to come.
S urveying cmd prospecting
A serious shortage of detailed information about the surface of
the sea oor and its underlying geology has presented a considerable
barrier to the discovery and exploitation of marine mineral resources.
A mining company moving into practically any part of the land
masses can expect some kind of geological plan to be available,
whereas in the oceans even the shallow continental shelf regions are
often virtually unsurveyed. When the search for natural gas moved
from the Netherlands into the North Sea, for example, the oil
companies had to carry out preliminary surveys and mapping——
and this in an area almost enclosed by advanced nations with strong
maritime traditions. Little is known about the chemical and physical
forces at work in the marine environment except where they
impinge on the land to shape the coastline. And this general im—
poverishment of marine geology was, until very
recent times,
reected in the small basic kit of instruments and techniques
available for under—water investigations.
_
On the land, four basic geophysical techniques are used to
investigate geological structures: electrical, gravitational, magnetic
and seismic. These have provided the starting points for the
evolution of marine systems. ln some cases—for example, magnetic
techniques—little alteration of already existing equipment has been
necessary; but with what is probably the most important technique,
seismic proling, advanced systems have been developed to take
advantage of the larger amounts of data which can be obtained in
the marine environment.
Electrical techniques rely essentially on changes in naturally
occurring or induced electrical currents brought about by the
geological structures through which they pass. Theoretically they
show considerable promise, but even on the land electrical tech—
niques are generally restricted to probing structures near to the
surface (including the detection of archaeological remains). At
present greater restrictions apply to their application in marine
The Last Resource
Large companies are slowly moving towards the idea of exploiting
the oceans, some are already searching for new mineral deposits,
but no matter how strong the current emotional sway towards this
neglected resource, the number of commercial marine activities are
likely to remain restricted to a few paying propositions for some
years to come.
S urveying cmd prospecting
A serious shortage of detailed information about the surface of
the sea oor and its underlying geology has presented a considerable
barrier to the discovery and exploitation of marine mineral resources.
A mining company moving into practically any part of the land
masses can expect some kind of geological plan to be available,
whereas in the oceans even the shallow continental shelf regions are
often virtually unsurveyed. When the search for natural gas moved
from the Netherlands into the North Sea, for example, the oil
companies had to carry out preliminary surveys and mapping——
and this in an area almost enclosed by advanced nations with strong
maritime traditions. Little is known about the chemical and physical
forces at work in the marine environment except where they
impinge on the land to shape the coastline. And this general im—
poverishment of marine geology was, until very
recent times,
reected in the small basic kit of instruments and techniques
available for under—water investigations.
_
On the land, four basic geophysical techniques are used to
investigate geological structures: electrical, gravitational, magnetic
and seismic. These have provided the starting points for the
evolution of marine systems. ln some cases—for example, magnetic
techniques—little alteration of already existing equipment has been
necessary; but with what is probably the most important technique,
seismic proling, advanced systems have been developed to take
advantage of the larger amounts of data which can be obtained in
the marine environment.
Electrical techniques rely essentially on changes in naturally
occurring or induced electrical currents brought about by the
geological structures through which they pass. Theoretically they
show considerable promise, but even on the land electrical tech—
niques are generally restricted to probing structures near to the
surface (including the detection of archaeological remains). At
present greater restrictions apply to their application in marine