Tuesday, September 2, 2014

Day 3

Tuesday 2nd September, 2014

Oh what a night ! Yesterday we sailed through rough seas that had the boat rolling on 3 meter waves. Here is a peek of how things looked like from the upper deck: click video. Weather conditions made it very difficult for some of us to make it through their shift, more importantly this made data collection impossible, so much so that it was decided to sail north and work on another study area there.

At this new area we started again with collecting multibeam and seismic reflection data. From this data we highlighted several locations for possible sediment gravity coring. Coring refers to the process were an elongated metal tube is inserted into the ground. The underlying material, such as the sedimentary layers, is 'trapped' within the tube, and brought back on board. The sediment cores reflect the development of the local seafloor throughout time.

An example of a core from a previous CUMECS mission. See more details here.

It was decided to first take a core on a terrace inside a canyon (Google map). The coring system was first deployed in the afternoon from the back deck. This requires connecting the system (core + weight) to a +2,000 m long cable. The core system is lowered to 10 meters above the seafloor, and then it is left to free fall to the seabed.

The core + 1 ton of weight being moved to the edge of the back deck.

The core system is aligned vertically, ready for deployment.

The core is gently pulled back up to the surface. Once on board the vessel the core is opened and cut into sections, labeled, and stored in refrigerated system to be analysed in a laboratory onshore.

Veerle measuring 1 meter length of core to be sawn off and stored.
Aaron labeling the core, marking the top and bottom of each section, and taking note of the core sequence.
Another core was later taken at the bottom of the canyon, across the channel, late at night. Total core recovery today was circa 5 meters! :)

Working hard late at night. The second core being prepared for storage.

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