Tuesday, April 11, 2006
Depth sounding
I came across this great map recently at the University of Hawai'i site. I’ve been reading about the first successful Atlantic submarine cable, and one of the things that struck me was how little they knew about the sea floor on which they were l
aying this hugely expensive piece of wire. They had nothing like this, which may have been a good thing; had they seen this I’m not sure it would have seemed so possible.
As it was, the US Navy had done a depth survey across much of the proposed route prior to the Civil War (our great-great-great grandparents’ tax dollars at work) and had proposed the existence of a “telegraphic plateau” – a stretch of relatively shallow water between Newfoundland and Ireland with what appeared to be a fairly smooth surface composed of microscopic shells, showing no evidence of currents or abrasive gravel.
The survey was done with soundings taken at regular intervals with an ingenious device invented by a Lieutenant Brooke that dropped a large iron ball with a specimen-collecting tube to the bottom. When it hit bottom, the tube detached, leaving the ball down there, and was brought back to the surface with a sample of the material from the bottom.
What will future geologists and archeologists make of a neat line of identical iron balls stretching across what was once the bottom of a vast ocean?
aying this hugely expensive piece of wire. They had nothing like this, which may have been a good thing; had they seen this I’m not sure it would have seemed so possible.As it was, the US Navy had done a depth survey across much of the proposed route prior to the Civil War (our great-great-great grandparents’ tax dollars at work) and had proposed the existence of a “telegraphic plateau” – a stretch of relatively shallow water between Newfoundland and Ireland with what appeared to be a fairly smooth surface composed of microscopic shells, showing no evidence of currents or abrasive gravel.
The survey was done with soundings taken at regular intervals with an ingenious device invented by a Lieutenant Brooke that dropped a large iron ball with a specimen-collecting tube to the bottom. When it hit bottom, the tube detached, leaving the ball down there, and was brought back to the surface with a sample of the material from the bottom.
What will future geologists and archeologists make of a neat line of identical iron balls stretching across what was once the bottom of a vast ocean?
