You are here

Gemini-Oscostar Volcanic Complex

Vent Sites: 
Gemini South
Oscostar (= Eastern Gemini)
Location on map: 
National Jurisdiction: 
Maximum or Single Reported Depth (mbsl): 
Tectonic setting: 
Volcano Number (if applicable): 
Host Rock: 
Deposit Type: 
Notes on Vent Field Description: 
located south of Coriolis Troughs; Cruise Summary FR08/2001: "recovery of sulfidic scoria breccia and agglomerate, and quenched native sulfur at Oscostar", "the first such hydrothermal deposits found at this location", "anomalously high concentrations of methane... at Gemini, Oscostar... accompanied by no light transmission anomalies"; SS06/2004 cruise report: "Shallow hydrothermal plumes were identified associated with both the summit regions of Gemini South and Oscostar."; Neptune Minerals Half-yearly report, 26 March 2008, accessed online 1 June 2015: "Prospecting licences PL 1627-1636 were granted to Neptune Minerals (Vanuatu) Limited... for an initial three-year period... The tenements are contiguous and cover the Gemini-Oscostar Volcanic Complex..."; tenement application Nautilus Minerals (SRK report 2011)
Year and How Discovered (if active, visual confirmation is listed first): 
2001 deposits and plume; 2004 plume and sulfide samples
Discovery References (text): 
McConachy, T.F., and Binns, R., RV Franklin Cruise Summary FR08/2001,, accessed 1 June 2015.
Arculus, R., et al. cruise report COTROVE-2004, SS06/2004 (
Other References (text): 
[McConachy et al., CSIRO Exploration and Mining Report 881F, Final cruise report FR08-2001, 318 pp., 2001].
SRK Consulting (2011) Nautilus Minerals Incorporated NI43-101 Technical Report 2010 PNG, Tonga, Fiji, Solomon Islands, New Zealand, Vanuatu and the ISA. Document Reference: NAT007 Nautilus 43-101 Technical Report 2011 Rev3.docx.