Ingenuity at Sea
01 deg 12'S
Longitude: 91 deg 22W
Wind Direction: SE
Wind Speed: 8 Knots
Sea State 3
Swell(s) Height: 2-4 Foot
Sea Temperature: 68°F (20°C)
Barometric Pressure: 1015.2 MB
Visibility: 12 Nautical Miles
Chees and bacon muffins
Eggs and potatoes
Bacon, ham and sausage
(Dried cereal is always available in the pantry)
OJ in a bucket
Croissant sandwiches: tuna, egg salad and meat
Chocolate chip cookies
Leg of lamb
September 15, 2001
by Christina Reed
Were looking for another way to help date when eruptions occurred
in the western Galápagos. Volcanologists always want
to know when eruptions happen, both now and in the distant
If Galápagos volcanoes spewed volcanic material high into
the air during previous eruptions, wind currents could have
sent the dust, ash and small particles of volcanic rock out
over the ocean where they would drift down to the seafloor.
Thin layers of volcanic ash in marine sediments provide good
evidence for eruptions. Small shells of animals and plants
in the sediment above and below the ash allow us to get accurate
Denny Geist, Mark Kurz and their students have
walked around many areas on Isabela and Fernandina. They have
seen evidence of eruptions that occurred before recorded history,
as far back as 300,000 years ago.
To find out if these ancient eruptions sent
ash and dust into the sky we needed some ingenuity. We cant just go around the corner to a store or order a
piece of equipment online.
To pick up the sediment we need something like
a tube. What we need is
a small sediment corer, Denny Geist says, something that can just
punch through the upper meter or so of sediment so that we can see if there are
any ash layers.
What we have on board is a rock corer. A piece
of equipment we have used to collect glass from the surface of
seafloor lava flows. The trick is whether it can be modified
to collect sediment instead of glass.
Dan wanted to know if we could convert his rock corer into a sediment corer, Todd
Ericksen says. Basically you have a pipe that plugs into the seafloor and
traps the sediment as it pulls back out. He described what a corer should look
like and I tried to build it from what we had.
Todd found an old flexible hose that fit inside
the rock corer and made a core catcher for the tip out of some
thin strips of stainless steel. The core catcher allows sediment
into the hose but prevents it from falling back out on the way
to the surface. Then he used a brass fitting for a nose cone
to hold the core catcher in place. Once I made it, I was hoping they would use it, Todd
says. Ive actually never seen a sediment corer before.
After bashing into the seafloor at 80 meters
per minute and being hauled up, the corer appeared on the surface.
Once on deck, everyone gathered around. There was sediment on
the tip but none in the tube. After removing the core catcher
we realized why. The corer hit a hard layer of glassy volcanic
gravel that stopped it from going very far into the sediment.
Inside the core catcher we found gray-green sediment and bits
of volcanic glass - great samples but not the ash we were looking
for. If we have time we will try it again.
[Back to top]