Our expedtion to explore the hydrothermal activity and mineralisation of the Kermadec arc volcanoes is now over. We arrived back in Auckland yesterday, after a successful three week research cruise. Amongst the discoveries that were made were areas of present day and ancient hydrothermal activity, relatively fresh lava flows from previously uninvestigated volcanic craters, and […]
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Sentry is the showpiece of our 2011 expedition to the Kermadec Arc Volcanoes. It is an autonomous underwater vehicle (AUV) that has been developed by the team at the Wood’s Hole Oceanographic Institution who are world leaders in submarine technology. Unlike the other devices that are put over the side of the ship and lowered
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Along with biological specimens, the sled brings a lot of rock off the sea floor. Christian Timm sorts through all the samples, cuts some of them up with a rock saw, and packs and labels them to be studied in detail back at GNS Science. The different minerals present in the samples will be analysed
Fabio Caratori Tontini is interested in measuring the magnetic properties of the rocks on the sea floor. Because most of them are volcanic lavas that contain a lot of iron, they have become magnetised as they cooled and solidified in the presence of the Earth’s magnetic field. When the hot geothermal liquids pass through them,
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Hydrothermal activity in undersea volcanoes is largely the result of sea water descending into the crust, being heated up and then chemically breaking down the surrounding rocks as it rises back up to the sea bed. These mineral rich fluids then re-enter the water column either diffusely over a wide area, or out of one
The first image shows the depth profile created by the ship’s sonar as it passed over the summit of Clark Volcano. It has the classic cone shaped profile of a typical land volcano such as Taranaki. They stick up above the deeper plains of the ocean floor and provide quite different habitats for deep sea
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We have now been traversing above Clark Volcano for several days, and a variety of surveys have been operating, including dredging for mineral and biological specimens, photography of the sea floor, magnetic surveys and water chemistry sampling. The technological centrepiece of our expedition to the Kermadec Arc is a strange object known as ‘Sentry’. Sentry
TOWCAM is an underwater camera that is lowered down to the sea floor and pulled along just above the bottom on a long winch line. It has an altimeter on it that allows the scientists to pull it up or lower it to keep it just above the bed as the ship drags it along
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One of the amazing tools that is on the Tangaroa is a multibeam sonar scanner that maps the contours of the sea bed as the ship travels along. It sends high pitch sound waves downwards in a fan shape and calculates the shape of the sea floor from the complex acoustic reflections. Over the last
Here is a map of the ocean floor north of New Zealand. The different colours represent water depth, red and yellow are shallower than the blue and purple areas. The deep Kermadec Trench that marks the plate tectonic boundary is an obvious feature, with the Kermadec Ridge running parallel to the West (left) of the
Message in a bottle Read More »