1 week 2 days
Expedition 368 South China Rift Margin
On-board Education Outreach Officers: Amanda Wolfe<, Shuhao Xie, and Gailun Zhang
Along the South China Sea Rifted Margin (SCSRM) a thinning crust of Earth's outermost shell, the lithosphere, creates a mystery to unravel. Expeditions 367 and 368 of the International Ocean Discovery Program are working together over the course of 4 months at sea to uncover the processes of continental break up. By retrieving core samples from the bottom of the SCSRM the team of 66 international scientists will look back in time, the geologic record, at the opening of SCSRM.
What could be happening at the SCSRM and why do we care? Scientific understanding of plate tectonics helps us explain the basic physical features around the world as well as how to predict natural disasters. Simplified, all of Earth’s land and water sit on large, moving plates made of solid rock. These plates make up the Earth’s outer shell, and when these plates move, mountains, continents and oceans are formed, volcanoes erupt, the Earth quakes, and the ripple effect of those phenomena can cause tsunamis! But what causes this movement? One of the culprits are Divergent zones which are areas where the plates are thinning and new crust is formed. The SCSRM is an example of a divergent plate boundary where a new ocean basin is being formed as the crust weakens and breaks.
There are two well known types of divergent boundaries in deep sea rifting margins. A magma-rich margin where large amount of volcanism and fast spreading occur and a low magma type where a slow hyperextension and thinning of the Earth's crust occurs. It is predicted from previously analyzed seismic data that the SCSRM is like the later kind of divergent boundary. The SCSRM shares many features with the well-studied margins of Iberia-Newfoundland with one exception. At the Iberia-Newfoundland margin the plates are slowly spreading at a rate of 0-1 cm per year while the SCSRM spreads at an intermediate measuring 3-5 cm a year! The kind of rock found at the Iberia-Newfoundland margin was serpentinized mantle (typically a soft green rock) which would indicate that the mantle rock was exposed to water which is one of the hypotheses for how plate break up occurs. However, with the different rate of spreading at SCSRM in this 150-200 km wide zone we may be looking at a new model for the mechanisms of plate weakening. Depending on what is retrieved in the deep sea core samples, the scientists will be able to confirm or refute whether the South China Sea Rifted Margin is similar to the well studied Iberia-Newfoundland margin or a new type of seafloor spreading rift margin!
Please join us by following the process of discovery aboard the JOIDES Resolution!
- Twitter #exp368
Education Outreach Team:
Amanda Wolfe is a High School Biology and Project Lead the Way Teacher who has been working with the National Science Teachers Association this school year. Amanda will work with you to provide live broadcasts with the scientist on board the JOIDES Resolution. She will be reporting stories from Expedition 368 on her blog<. Further more, she will be working to develop lessons that model real science in the field. She looks forward to working with you to share the passion for discovery at sea!
Shuhao Xie is a journalist and documentary director who works in Shanghai TV Station. He will be capturing the stories on board theJOIDES Resolution through high quality photos and video of the Expedition 368. These stories will certainly increase public interest about the International Ocean Discovery Program and the process of science at sea!
Gailun Zhang is a reporter for the newspaper Science & Technology Daily in Beijing (http://www.stdaily.com/<). She will be producing daily reports and short videos for her column about the science happening on board the JOIDES Resolution Expedition 368. Here is an example<.