The Rio Grande Rise is a largely unstudied large igneous province (LIP) in the South Atlantic with an area similar to Iceland – a true terra incognita. Expedition NBP1808 explores this region during October-November 2018. On this website expect to see everything from scientific information to thoughts about life at sea aboard the research vessel and ice breaker Nathaniel B. Palmer.

“How did the Rio Grande Rise form?” is the main question that we seek to answer. With dredges we collect rock samples of the lava flows that formed the Rio Grande Rise (RGR) structure roughly between 80 and 40 million years ago. Radioisotopic (40Ar/39Ar) dating and geochemical data on these rocks will provide information how the Rio Grande Rise formed in the context of the opening South Atlantic and its relationship to a sister volcanic system on the African plate, the Walvis Ridge. Because the magmas that formed Rio Grande Rise may come from deep in the mantle, our samples provide a rare geochemical window to the state of the core-mantle boundary. In addition, we will use the new data to refine plate motion models of the South American and African tectonic plates. Previous research has been conducted on Walvis Ridge, and it is now the RGR’s turn! We are collecting this data by mapping and dredging 30-40 seamounts, rift zone valleys, and steep escarpments in the Rio Grande Rise, from 28°S and 39°W to 39°S and 20°W. The depths of these features range from about 4 km to 1 km (2.5-0.6 miles).

To read more about the goals of this expedition, see the Scientific Objectives.

Here you can find daily updates and news of our progress. Check back in for new information!

Day 36 - November 23, 2018
We finally finished sawing Dredge 21 and upped our sample count from 14 to 42. Many of the samples we picked up are dropstones—rocks carried by icebergs that dropped to the seafloor as the ice melted. The rocks are much different than what we expect to find while dredging the ocean in this area. Read more

Day 35 - November 22, 2018
Happy Thanksgiving! We had three different kinds of pie today, all of which were well-received. Today was a busy day for wildlife (a whale and dolphins were spotted), and it was also the end of our ping pong tournament. Read more

Day 34 - November 21, 2018
We managed to complete one dredge today and start another. Dredge 21 of Schamali Escarpment (named after a star in Libra) picked up a couple large rocks and many more small rocks. There’s a lot to saw, so we’ll check back in with that later. The next dredge is also named after a star in Libra, Elgenubi Escarpment. Read more

Day 33 - November 20, 2018
We decided to dredge Alhague Seamount again. It got stuck for 30 minutes at the very end of the dredge, but we got it free and pulled it up. It consisted mostly of brecciated volcaniclastics—rocks formed from volcanic eruptions that broke apart and then were cemented together by some other material. Read more

Day 32 - November 19, 2018
Today was spent transiting and catching up on work. We started a ping pong tournament in our free time, though! Read more

Day 31 - November 18, 2018
We ended up being stuck for around 12 hours at Alshain Seamount. When the dredge bag finally came up, a couple of the boulders were so huge that we had to sledgehammer them while they were still in the bag because they wouldn’t budge. Read more

Day 30 - November 17, 2018
Unukalhai Seamount finally gave up what she was holding onto! We got a lot of large boulders and a tiny bit of coral. The samples we cut are all basaltic, but they are less altered than previous dredges. We’re going to take lots of these for analysis. Read more

Day 29 - November 16, 2018
We’re currently dredging Unukalhai Seamount. We’ve been stuck for a few hours and aren’t free, but we’re not giving up hope yet! Read more

Day 28 - November 15, 2018
We are continuing along the long string of seamounts in the southeast of the Rio Grande Rise. Once we survey and dredge these, however, we will be dredging no more seamounts for the rest of the trip. Today’s dredge of Marfik Seamount (again of the constellation Ophiuchus) brought up a small amount of samples—just a few basalt clasts and a fair amount of coral. Read more

Read All News Updates
Read short reports presenting some of the science behind the cruise, as well as blog stories about life on the RVIB Nathaniel B. Palmer. Don’t worry about having to do extra reading—the reports are written with a general audience in mind, and will cover topics mentioned in the Scientific Objectives as well as other basic geology topics.

Science Report 1 - November 23, 2018 - Reconstructing Earth: Magnetics and Magma
One of the scientific goals of the NBP1808 cruise to the Rio Grande Rise is to collect measurements that will improve the plate tectonic reconstruction of the opening of the South Atlantic. How is this done? We are able to measure magnetic anomalies originating in the oceanic crust, which lies 1000-4500 m below the ship. Read more

Read All Science Reports
Rio Grande Rise 2018 Expedition
Browse through a gallery of pictures from the NBP1808 cruise, showing life aboard the RVIB (Research Vessel Ice Breaker) Nathaniel B. Palmer as we explore the Rio Grande Rise off the coast of Brazil in the South Atlantic.


Co-PIs on the Rio Grande Rise project: (From left to right) Cornelia Class, Anthony Koppers (Chief Scientist), William Sager.


The members of the NBP1808 science team.

View Image Gallery

Planned Cruise Track
This map shows the planned path of the ship as we make our way around the Rio Grande Rise. This map includes our detour to avoid the storm.

See Larger Version
Scientific Goals
  • Use 40Ar/39Ar geochronology to determine whether the Rio Grande Rise formed along micro-plates, as an age-progressive feature like most of Walvis Ridge, or from a short-lived large eruptive event
  • Investigate whether the Rio Grande Rise displays three geochemically distinct zones similar to the triple-zoned younger part of Walvis Ridge using major-trace element and Sr-Nd-Hf-Pb isotope data
  • Collect magnetic anomaly data to help strengthen the age model for the South American tectonic plate
  • Explore the formation of the Rio Grande Rise as shaped by plume dynamics and/or shallow tectonics
  • Determine whether the geochemical mantle sources are related to a zone of probably dense material at the base of the mantle called the African Large Low Seismic Velocity Province (LLSVP)
A team of 17 students and scientists led by Chief-Scientist Anthony Koppers will be at sea for seven weeks, mapping and dredging troughs, cliffs, and seamounts in the Rio Grande Rise region off the southeast coast of South America. The team consists of 11 graduate students in geophysics, geochronology, and geochemistry; 4 undergraduates; 1 post-doc; and 3 professors from Oregon State University, Lamont-Doherty Earth Observatory of Columbia University, and University of Houston. Over the next few weeks we will keep you updated as we map and dredge the Rio Grande Rise and expand the knowledge of the general area.