Map showing planned research targets for the 2008 Lau Basin research expedition, TN228.

2008 Expedition to Lau Basin

R/V Thompson
November 13-28, 2008

Expedition to search for hydrothermal activity in the NE Lau region by conducting water-column plume surveys.  In conjunction with the water column work, expedition will also be doing bathymetric mapping of the seafloor using the shipboard EM300 system in areas where high resolution maps do not exist.  The primary targets are the NE Lau Spreading Center (NELSC) , the Mangatolo Triple Junction (MTJ, also called the Kings Triple Junction), and the large caldera named Volcano O (Caldera on map).

Plume Discovery-Expedition Update:

Location of the plumes discovered on the Lau Spreading Center during the 2008 expedition. (click for full size image)

Voyage TN227 of the R/V Thompson is presently conducting seafloor mapping and water-column plume surveys in the NE Lau region. We are currently over the NE Lau Spreading Center at ~15 deg 24’S, 174 deg 15’W. We have found that the water column over this back-arc spreading center is populated with an unusual suite of spectacular plumes at depths ranging from 1400 m up to 700 m below the sea surface. Some of our water column profiles detected over 5 distinct hydrothermal plume layers, and the shallowest of these plumes is over 600 m above any local topography. Furthermore the plumes are characterized by intense light scattering anomalies, high Eh signals, and in some cases very high concentrations of dissolved hydrogen. This represents a considerable increase in activity compared to the previous study conducted here on the R/V Kilo Moana in 2004 [German et al., g-cubed, 2006], and a suite of plume surveys conducted using IMI30 and MAPRs in July 2008. Based on our collective experience, these plumes have the physical and chemical characteristics associated with seafloor eruptive activity. During the remaining 6 days of this expedition, we plan to continue surveying the region and attempt to localize the source of this unusual activity. We had considered deploying Dan Fornari's camera system, which is also on board, but not all of the necessary components are on the ship. We ! believe The RIDGE community should consider this site as a focus for future Time Critical Studies activities, especially in conjunction with ship operations supporting the Lau ISS.

All updates from sea are be posted at:
http://ventslaubasin2008.blogspot.com/

More Information:

Background | Science Team

updated 10/9/2008