Slackjaw Sally here, writing from the Research Vessel Thomas G. Thompson. I’ll admit that I really enjoyed sunbathing in South Africa and seeing the sites, but I’m glad to be back onboard a research vessel. It’s been two years and I missed the excitement of exploration.
We’re on our way to the Marion Rise in the Indian Ocean, south of Madagascar. Our study site is on the southwest Indian Ridge from 39⁰ to 47⁰ E. I’m with an international team led by scientists from the United States (Henry Dick), China (Huaiyang Zhou) and Germany (Jürgen Koepke) and including researchers from China, England, Germany, Indonesia, Italy, South Africa and the United States. Luckily for me, everyone speaks English! It’s fun hearing all the different accents.
The Marion Rise is an enormous area of elevated seafloor and we’re here to find out why it was uplifted. Available evidence about Marion Rise geology indicates that it is very different from the better-known Icelandic Rise on the Atlantic Ridge. The Icelandic Rise demonstrates extensive volcanism, suggesting that it was pushed upward by a large, hot, mantle plume, but the Marion Rise is a region with limited volcanism. So, what’s going on? How could this area be uplifted so high when its geology is so different? These intrepid scientists seek to find out.
We’ll map the topography of the sea floor under our path using the ship’s sonar to make 60-meter resolution maps in two previously unexplored areas. The Sentry autonomous submarine will be used to map regions of interest within these areas at 1 to 2-meter resolution. These maps will help us decide where to collect rocks by dredging- literally by dragging a wire basket across the sea floor. We’ll collect geophysical information (gravity/magnetics) using instruments from the ship. Of course, we’re also hoping to discover new hydrothermal vent systems while we’re out here.