Wednesday, June 8, 2011

Blog about maps

June 7th

I like maps. Even as a child I enjoyed following the progress of a car trip on the road map. Now we have a world map on the wall in our house, to more easily visualize where family members are and to fantasize about where we might go someday. As a marine geologist, much of what I do involves learning about where things are relative to each other – is the muddy seafloor only on the continental shelf or does it extend down the slope? Are the mid-ocean ridge basalts exposed on all of the fracture zones? How did this piece of granite (typical of continental crust) get out here into the middle of the Drake Passage (hint… think about icebergs…)?

Everything we do during this cruise is recorded with the date, time, and position. I use those positions to create maps showing where we have been, what we did while we were there, and what we found. During the cruise, we use these maps to plan where we should take the next samples. After the cruise, I will work with Rhian and Laura to try to understand why corals live in some places and not in others. Maybe one species likes steep slopes with rocky outcrops while another is found only in places where we found mud.

Just from looking at the ship’s trackline, you can see a story unfolding. In the map below, the colored dots on the black trackline mark each passing hour. Each day has a different color dot. This map shows the 5 days that we worked at Interim Seamount. We arrived from the south in good weather – the hour marks are far apart because we were travelling at 10 knots. Near the center of the map you can see several places where the hour marks are almost on top of each other. These are places where we worked on station or only moved a little for a few hours while dredging or collecting bottom photographs. On the eastern side of the map, there are two almost parallel track line with hour marks pretty far apart – this is where we were collecting multibeam bathymetry data, moving right along at about 8 knots. When we left Interim Seamount, the weather was bad. We had big waves (taller than a 2-story house!) and the ship could only move ahead slowly, at about 3 knots. This is about as fast as you can walk!

By Kathy

Weather: temperature 35 °F, windchill 3 °F, wind speed, cloudy

Map of Interim Seamount showing the ARV NB Palmer’s trackline – faster when we arrived, and slower when we left! (K. Scanlon).

 Kathy demonstrating it’s very important to keep a close eye on the ship’s trackline (R. Waller).

Ben bringing in the niskin bottle, used to sample water at depth, which was attached to the Drop Cam for the first time today (R. Waller).
Andrea sampling water from the Drop Cam niskin bottle with the help of Laura (R. Waller)

The day shift drying, sorting and packing the multitude of fossils from the Cape Horn dredges (L. Robinson).

Mariana working on the biology that came up with one of the dredges today. Cape Horn is so far proving to be a treasure trove for both living and fossil corals (R. Waller).

1 comment:

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