A new gas-tight isobaric sampler for hydrothermal fluids

• Published in: Deep-sea research. Part I, Oceanographic research papers Vol. 49; no. 1; pp. 189 - 196
• Main Authors: Seewald, Jeffrey S., Doherty, Kenneth W., Hammar, Terence R., Liberatore, Stephen P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2002; Elsevier; Pergamon Press Inc
• Subjects: Dissolved gases; Earth sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Fluid dynamics; Geochemistry; Hydrothermal fluid sampler; Instrumentation; Instruments; Mineralogy; Oceanography; Physical and chemical properties of sea water; Physics of the oceans; Silicates; Thermodynamics; Vents; Water geochemistry; East Pacific Rise; Northeast Pacific; Juan de Fuca Ridge; North Pacific; Dissolved gases; Instrumentation; Hydrothermal fluid sampler; Vents; sea water; carbon dioxide; hydrothermal circulation; propane; hydrogen; vents; ethane; instruments; hydrochemistry; ocean floors; methane; Pacific Ocean; dissolved materials; gases
• ISSN: 0967-0637; 1879-0119
• DOI: 10.1016/S0967-0637(01)00046-2

A new gas-tight isobaric sampler for the collection of hydrothermal fluids venting at the seafloor has been designed, constructed, and tested at a ridge-crest vent site. The new device is constructed of chemically inert titanium, is gas-tight to 450 bar and can be used to sample fluids with temperatures up to 400°C. Compressed gas is used to maintain the sample at seafloor pressure before and during sample withdrawal onboard ship, allowing subsampling without degassing the fluid remaining in the sampler. This feature eliminates the need to collect separate gas-tight and major element samples since a single fluid sample can be analyzed quantitatively for major, trace, semi-volatile, and volatile components. The sampler fill rate is regulated to minimize entrainment of ambient seawater during collection of fluids from environments characterized by low fluid flow such as diffuse hydrothermal vents. In addition to deployment at the ridge-crest, the samplers can be used to collect gas-tight samples from other subseasurface environments such as hydrocarbon seeps, areas of methane-gas hydrate formation, cold seeps associated with serpentinites, regions of groundwater egress to the oceans, and the water column.