Hugh's Release

The long piston corer has enabled us to recover several amazing geological records. Of course, we won't know the details until we finish literally years of laboratory analysis. But for now we can state categorically that there is no other piston coring tool that can be deployed from a US oceanographic ship that produces such a long and high quality sediment core. While it was previously ordinary to recover 10 m long piston cores and occasionally up to 20 m of mud, the CDH has rather routinely allowed us to recover over 30 m of sediment. This increased length of cored sediment, of course, increases the amount of geological time recorded by the sediment. This innovation was only made possible by the vision, knowledge, and stubbornness of Jim Broda, Senior Research Specialist at WHOI. If you have followed the blog, you know all of this already.

But, last night we had an event that demonstrated that using the CDH is not "routine." For the second time on the cruise we had a failure to release: after two hours descending on a winch to 3500 m water depth, the corer did not respond to the signal transmitted from the ship. What to do?

After two hours of recovery, another few hours for repair with rubber bands (really) (and more), then back to the seafloor. Again, no communication. Another failure.

We were looking at the possibility that we would not be able to recover what looked (in the seismic record) to be some of the best sediments on the whole expedition.

A 3.5 KHz seismic reflection profile image of the
sediments in the upper 30 meters below the seafloor.
These sediments are stratified and a bit folded,
probably due to slumping. Our long core samples
almost all of this section.

The old release mechanism, including rubber bands.

Instead, Hugh Popenoe (whose father is a well known marine geologist) and Tito Collasius, working throughout the night, undertook a complete reconfiguration of the release mechanism, eliminating the above solenoid, release mechanism, and rubber bands.

Hugh tries out his new release mechanism. Professor
Cleverson Silva, from UFF, Niteroi, Brasil, stands
by (he is another big time hero, but that is another story).

Tito (left) and Jim check out their retrofit in first light.

Thirty-six hours after arriving at the station, we recover a beautiful, 30 m long core. I've been involved in a lot of field work through the years, enough to say with some authority that this was a major league, prime time save. All for science!