Metal Detector Locates Historic Artifacts
A
group of Americans are working with Ecuadorian archaeologists
to recover artifacts from a Spanish ship dating to the early
1600’s. Wreckage
is spread over a large area in relatively shallow water which
is typical of ships that were wrecked in hurricanes.
They were driven up onto the shore or into a reef, then
literally torn apart by wind and waves in the shallow water.
The first step for the archaeologists was to map the
site using a magnetometer, a super sensitive metal detector
that locates iron and steel objects.
A magnetic map of the area was produced showing where
the concentrations of iron targets, like cannons, were buried.
Joel Ruth is one of the Americans involved in the project. He reports, “To date we have recovered 26 arquebuses
(cannons), several with barrels stuck vertically into the
seafloor. Some of
them are in a remarkable state of preservation.
According to our research there were regulations
dictating how much of military force was to required to
accompany ships carrying precious cargo.
We believe the cannon are from warships that were
providing protection for the treasure galleons.
If we’re right there should be at least 14 more
cannon down there.”
What the magnetometer survey couldn’t
tell the archaeologists, was where the precious metal objects
were located. A
decision was made to bring in a metal detector which would be
capable of locating the nonferrous objects like gold and
silver bars. The
area was resurveyed using a Fisher Pulse 10 boat-towed metal
detector. Ruth
was one of the operators of the detector.
Early in the search operation he reported, “I feel we
are in an area consisting of forward hull material and a
weapons store. This
area registered one magnetometer reading and five from the
Pulse 10. After completing verification of objects in the current hole,
we will begin trenching diagonally towards another huge mass
which was detected by the Pulse 10.
The anomalies ahead are exclusively nonferrous in
nature as the magnetometer registered nothing at that
location.”
In his latest report Joel excitedly
said, “Yesterday we uncovered a chest!”
But the chest turned out to be more of a case.
“All this work is taking place in zero visibility
conditions and by braille search techniques, so you have to
forgive our earlier rough estimations of what was then still
mostly buried in clay.”
As it turned out the case is made of red mahogany and
appears to filled with rapier blades (swords)...or at least
that is what is showing at the one end I chipped away.
What is interesting is that these foils are stainless
steel and in perfect condition.
Stainless steel, especially Toledo steel, was a very
expensive and rare commodity in 1612.
It was usually reserved for making the finest blades
and swords. What
appears to have preserved these so well is a large iron spike
which fell atop the case and has acted as sort of a
sacrificial anode, bearing the brunt of the sea’s galvanic
electrolysis process while sparing the contents of the case.
The nails holding the case together also appear to have
performed the same function.
The entire concretion may eventually be dissolved in
muriatic acid and the contents extracted and conserved.”
“After removal of the box the entire
excavation continued to read positive for nonferrous metal so
the diver continued to blow the clay away with a high pressure
water hose and trenched two feet deeper in the clay.
What he discovered is a concentrated mass of shipwreck
material which appears to be several yards wide in diameter
and at least 8 inches to a foot thick.
He cleared quite a big patch of it, and again due to
zero visibility, was unable to determine while underwater what
it was. But the
Pulse 10 screams across the entire exposed area.”
“The weather has now taken a turn for the worse, keeping
us from getting back on site.
As soon as it breaks, we’ll return and attempt to
separate and raise a bigger chunk of this mass. We need to
find out if the contents are consistent with the first sample,
but more importantly to see
if there is even more material buried deeper beneath this huge
concretion. There
is a lot of treasure hidden somewhere on this site, and we
intend to find it.”
