Meeting

Review of Japanese Taiga project 1, Indian Ocean

InterRidge-Japan community conducted an interdisciplinary research project TAIGA, Trans-crustal Advection and In-situ biogeochemical processes of Global sub-seafloor Aquifer, from 2009 to 2013. The flows and chemical compositions of subseafloor fluid are regulated by tectonics, and are modified by the host rocks. During 5 years project, we selected three integrated study sites of different tectonic settings and carried out multi-disciplinary studies.

Review of Japanese Taiga project 2, Okinawa Trough

The Okinawa Trough is a back-arc basin behind the Ryukyu trench-arc system and located along the eastern margin of the Eurasian continent. Based on geophysical and geological studies, the Okinawa Trough is considered a back-arc basin in the rifting stage. Such a tectonic setting is characterized by development of normal faulting in brittle continental crust and frequent intrusion of a magma, which can be expected to provide favorable environment for development of a hydrothermal system.

Tectonic Processes of the Australian-Antarctic Ridge

The Australian-Antarctic Ridge (AAR) has been remained uncharted until 2011 because of its remoteness and harsh weather conditions. From 2011, the multidisciplinary ridge program initiated by the Korea Polar Research Institute (KOPRI) surveyed the little explored eastern segments of the Australian-Antarctic Ridge (AAR) to characterize the tectonics, geochemistry, and hydrothermal activity of this intermediate spreading system.

First Ultramafic-Hosted Hydrothermal Sulfide Deposit Discovered on the Carlsberg Ridge, Northwest Indian Ocean

During R/V Zhukezhen Cruise DY33, Leg 1 (February 09 to March 29 2015, chief scientist: Dr. Xiqiu Han), we conducted comprehensive geophysical mapping, hydrothermal plume surveying, video sled observing and geological sampling along the slow-spreading Carlsberg Ridge. The most significant result of this leg is the discovery of a new ultramafic-hosted hydrothermal sulfide deposit which named Tianxiu Field at 63.82°E, 3.69°N in water depths of around 3450 m, on the southern rift-valley wall, ~5 km from the adjacent rift axis.

Sulfide Mineralization from a Newly Discovered Hydrothermal Field on the Carlsberg Ridge: Evidence from Mineralogy and LA-ICP-MS study

The mafic-hosted and inactive Wocan hydrothermal field, located on an axial volcanic ridge at a depth of ~3000 m at 6°21′N along the slow-spreading Carlsberg Ridge, was discovered and sampled by TV-grab at five stations in 2013 on the DY28 cruise. Preliminary investigations show that the field consists of two mineralization mounds called Wocan-1 which located on the east, and Wocan-2 which ~1.7 km away from Wocan-1 on the west.

Seismic evidence of a detachment fault near the fossil spreading center in the Southwest Sub-basin, South China Sea

In 2010, we conducted an ocean bottom seismometer (OBS) experiment surveying the fossil spreading center in the Southwest Sub-basin of the South China Sea. The detailed velocity model, simulated by two-dimensional ray tracing, shows a strong lateral variation in velocity structure across the spreading ridge.

Saldanha hydrothermal field: the role of the sediment-cover in the preservation of ore-forming minerals

Title: Saldanha hydrothermal field: the role of the sediment-cover in the preservation of ore-forming minerals

 

Authors: Ágata Sofia C. M. Alveirinho Dias and Fernando J. A. S. Barriga

E-mail: ascdias@fc.ul.pt or agata.dias@usj.edu.mo

Structure and dynamics of the Southeast Indian Ridge and off-axis volcanism, 129°E to 140°E: Preliminary results of the STORM cruise

Structure and dynamics of the Southeast Indian Ridge and off-axis volcanism, 129°E to 140°E: Preliminary results of the STORM cruise

Hydrothermal Exploration of Mid Ocean Ridges: Where Might the Largest Sulfide Deposits Occur?

Hydrothermal Exploration of Mid Ocean Ridges: Where Might the Largest Sulfide Deposits Occur?

C.R.German         S.Petersen            M.D.Hannington

Review of Japanese Taiga project 3: Geodynamics of the Southern Mariana Trough Back-Arc Basin

Review of Japanese Taiga project 3:

Geodynamics of the Southern Mariana Trough Back-Arc Basin

Nobukazu Seama