NSF Forms - Ridge 2000 Program

and trace element analysis and interpretation of the Lau Basin samples. His participation is to
ensure analysis of any new samples from the Fisher cruise. For the current proposal, Langmuir will
oversee the project and supervise Standish and Bezos. Standish will carry out the U-series analyses.
Reagan and Sims will carry out 210 Pb measurements on samples that have significant 226 Ra excess
using both the WHOI and U of Iowa counting laboratories. Sims will oversee the U-series
measurements at WHOI, and Sims, Standish, and Langmuir will be the primary collaborators
involved in interpretation of the results.
Standish has extensive experience in low-level (MORB) U-series chemistry from his work at
WHOI [Standish & Sims, submitted; Standish 2005], and Sims is providing the necessary wellcalibrated
233 U, 229 Th and 228 Ra spikes so no spike calibration is involved in setting up the chemistry
at Harvard. The clean lab is also fully operational with low blanks and is currently being used for
chemical separations for Sr, Nd, Pb and Os as well as ICP-MS trace element chemistry.
Furthermore, Woods Hole and Harvard are a 90 minute drive from each other, facilitating frequent
interaction, exchange of materials and reagents, instrumental tests and so on. Therefore, while we
anticipate no more than the ordinary difficulties in setting up the chemistry at Harvard, we also have
the ability to carry out chemical separations at WHOI until the Harvard lab is operational, and
therefore the progress of the project will not be impeded.
In addition to the geochemical team, we are collaborating with a large number of other
investigators working on the Lau basin. In addition to the scientists involved in the Langmuir cruise
(German, Shanks, Fornari, Yoerger, Michael, Asimow) we are collaborating with Meg Tivey and
other PI’s from her cruise to facilitate comparison with chimney and water column data, we have
provided samples for substrate experiments, and are receiving samples and biological input from
Chuck Fisher from his cruise in September of this year. We are also collaborating with Terry Plank
who is working on samples from the Tonga volcanic front, which will be a valuable comparison to
our study. We are in touch with Hilton, Hanan and Castillo at San Diego who are carrying out a
complementary study of lavas from other portions of the Lau Basin. There is no overlap with the
work proposed here. Therefore our work and interpretations will take place in the context of multidisciplinary
investigations of this region.
The detailed work plan is as follows:
Winter 2006--- U-series chemistry set up at Harvard; Sample Selection on the basis of
geochemical and geological data;
March 2007 – March 2008 Primary period of U-series data acquisition on 30 samples
Dec 2007 --- Data presentation at Fall AGU
March 2008 – February 2009-- Quantitative modeling of data; Further acquisition of U-series
data; Preparation of publications.
8. BROADER IMPLICATIONS (CRITERIA 2)
The proposed work is part of a multi-disciplinary effort to understand the ocean ridge system
from melt generation in the mantle to volcanism and life on sea floor. The combination of U-series
age constraints with geologic and tectonic controls are central to understanding the hydrothermal
and biological components of the ridge system and will enable a much better understanding of
MOR architecture and construction. Basalts serve as the dominate substrate through which
hydrothermal fluids circulate, thus eruption ages are vital during discussion of the ever changing
fluid chemistry of these relatively ephemeral vent systems. Additionally, the attendant biologic
communities harvest the volcanic energy of these systems, making temporal constraints on lava
emplacement and construction similarly important.
D-14
0649641