Lavas covering about 2/3 of Earth's surface are erupted at submarine mid-ocean ridges, making it the most volcanically productive environment on the planet. This volcanism provides a major outlet for heat and matter in Earth's interior and plays a significant role in ocean chemistry and the ecology of deep sea marine life. This project is focused on the timescales and rates of very recent magmatic and volcanic processes at mid-ocean ridges, with a focus on interdisciplinary integrated study sites of the Ridge2000 program and other sites of opportunity where seafloor eruptions can be detected and quickly sampled. Radio isotopes 210Po and 210Pb are used and comprise the most important and reliable means to date young eruptions. The half-life of 210Po is only 138 days, as such, samples for 210Po-210Pb analysis require immediate processing. The broader impacts of the work are enhancing infrastructure for science by upgrading laboratory facilities to accommodate more dates, making methodological improvements in the dating technique, and keeping the lab ready to conduct short-fuse lava dating for current and future time critical studies of submarine volcanism.
This 5 year project was a study of the timing and duration of several recently active submarine eruptions and the events that happen during magma formation. Submarine volcanism is by far the most common type of volcanic activity of Earth, but eruptions there are very difficult to detect and observe directly, so scientists try to learn as much as possoble when we do have the opportunity to do so. The main part of this project was imporvement and application of a radioactive dating method for young submarine eruptions that can provide information on the sequence of events in an eruption with precision of 1 to 4 weeks using the naturally-occuring isotopes 210Po and 210Pb, with 138 day and 22 year half lives. This is critical informaton for understanding the progress of such erutptions, how they dffer from eruptions on land, how they impact sumarine geothermal systems, and how they affect the ecology of the sea floor. This project work on submarine volcanic eruptions at Axial Volcano off of Washington state, the East Pacific Rise (off of central Mexico), West Mata Volcano (Kingdom of Tonga), Loihi (Hawaii) and an analog eruption site in Iceland Krafla volcano). This reasearch project provided funds to expand our instrmentation, improve our methods, as well as study the aforementioned specific eruptons, so we will be ready to conduct similkar studies when the opportunity arises. Besides studying the timing of eruptions, we also employ isotopes 210Pb and 226Ra to look a how long magmas reside in the crust before they erupt and how they evolve chemically during that time, which are important parameters for understanding heat balance at volcanoes, the frequency of magma injection from below into volcanoes, and how frequently they erupt. Our work has been pulblished in multiple venues. One publication about submarine eruptions that we hope you will take a look at includes lots of imagery and explanation for a general reader. It is freely available at: http://tos.org/oceanography/archive/25-1_rubin.html
