Personnel

Members of our research group:

Collaborators and Associates:

Research Activities

Our research group is studying the effects of hydrothermal venting on the oceans at a variety of spatial and temporal scales. At the broadest scale, we are studying the circulation of the deep and intermediate waters of the Pacific Ocean. Specifically, we are using noble gas tracers, especially 3He, to map the patterns of oceanic circulation and mixing. Hydrothermal venting along the axis of the global mid-ocean ridge system and from certain volcanic seamounts produces hydrothermal plumes in the deep ocean which are enriched in 3He relative to ambient ocean water. Because these plumes have localized source regions, their distribution can be used to trace patterns of circulation and mixing. This is especially true in the Pacific Ocean, where the spreading rate of the volcanic ridges is very high, resulting in a correspondingly high rate of helium injection.

Measurements of oceanic 3He from the World Ocean Circulation Experiment (WOCE) Hydrographic Program have added greatly to our knowledge of the distribution of hydrothermal plumes in the deep Pacific, thereby providing strong constraints on the deep circulation in certain areas. Our research group has measured deep helium on several WOCE Pacific sections, including P1 (TPS-47), P3 (TPS-24), P16, P17, and P19, as well as NOAA expeditions RITS-89 and CGC-91. We are also in the process of analyzing deep helium samples from WOCE lines P13 and P18.

Helium Measurements in the Central Pacific

Here are some examples of our helium measurements in the Pacific Ocean. The map shows the location of two long WOCE sections, P17 and P19, relative to the Juan de Fuca Ridge (JdFR) and the East Pacific Rise (EPR). The JdFR and EPR are active volcanic ridges which are known to be sources of hydrothermal 3He in the deep Pacific. These helium data are reported in units of delta(3He)%, which is the percentage deviation of the helium isotope ratio from the ratio in air. To view the images of the helium data merely click on the appropriate link. There is also a plan view map of a large helium plume emanating from Loihi Seamount on the flanks of the Island of Hawaii.

Helium Measurements in the North Pacific Ocean

Our research group is part of the NOAA VENTS Program, and as such we have concentrated considerable effort in studying the Juan de Fuca Ridge in the northeast Pacific. Like the EPR to the south, the hydrothermal activity on the JdFR also produces a helium plume which can be traced for thousands kilometers into the central Pacific. The map below shows several sections along which we have measured deep helium. To view each section, merely click on the appropriate line below the map.

References

Lupton, J.E., Hydrothermal plumes: near and far field, in Seafloor Hydrothermal Systems: Physical, Chemical, Biological, and Geological Interscations, Edited by S. Humphris, R. Zierenberg, L. Mullineaux, and R. Thomson, Geophysical Monograph 91, American Geophysical Union, Washington, D.C., pp. 317-346, 1995.

Lupton, J.E., A far-field hydrothermal plume from Loihi Seamount, Science 272, 976-979, 1996.

Lupton, J.E., Hydrothermal 3He plumes in the Pacific Ocean, Ewing Symposium AGU Monograph, submitted, 1996.

Links to Other WOCE Helium Data