| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | March 26, 2010 |
| Latest Amendment Date: | January 11, 2012 |
| Award Number: | 0947956 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Jennifer Wade
jwade@nsf.gov (703)292-4739 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | April 1, 2010 |
| End Date: | March 31, 2014 (Estimated) |
| Total Intended Award Amount: | $350,002.00 |
| Total Awarded Amount to Date: | $350,002.00 |
| Funds Obligated to Date: |
FY 2011 = $118,865.00 FY 2012 = $119,763.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1200 E CALIFORNIA BLVD PASADENA CA US 91125-0001 (626)395-6219 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1200 E CALIFORNIA BLVD PASADENA CA US 91125-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Petrology and Geochemistry |
| Primary Program Source: |
01001112DB NSF RESEARCH & RELATED ACTIVIT 01001213DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
A major reservoir of water within our planet is the water bound in minerals that we would nominally consider to be anhydrous. Such minerals include olivine, garnets and pyroxenes. This water is most commonly bound in the form of hydroxyl (OH) groups. It has an important influence on a wide variety of processes in the geological world, and may be particularly important in the deep earth. This project follows on previous work by a team of researchers that has been studying these minerals for over two decades and is now focusing on an effort to use secondary ion mass spectroscopy (SIMS) in combination with infrared (IR) spectroscopy to quantify hydrogen concentrations in these phases. It is proposed to apply this technique to study processes relevant to hydrogen transport and its effects on kinetic processes in the Earth's mantle. The proposed program will be divided into a calibration effort, the measurement of the diffusion processes of hydrogen in the important upper mantle mineral olivine, and the characterization of minute inclusions of water that result from the gradual loss of bound water from its mineral host.
Researchers currently accept that a volume of water equal to or greater than all the water in the oceans of our planet is bound in minerals nominally considered anhydrous. This water is an important reservoir in the terrestrial water cycle, a source of volatiles that drives processes in the mantle, and an agent that impacts physical and chemical properties of the host such as diffusion, radiation stability, color, dielectric constant, and melting. The research proposed here will broaden our understanding of the important roles trace amounts of hydrous components play in the properties of solid materials. It will improve the ability of this laboratory to offer its services to a range of visitors who come to analyze hydrogen using these facilities. Furthermore, the community will benefit from our development of new standards for SIMS analysis of hydrogen in minerals, which will be shared with other labs. Traces of bound water in minerals also occur in a variety of synthetic products of our technological world such as semiconductor supports, optical crystals, fibers, and oscillator crystals. In many of these hosts, the trace components play a major role in determining the properties of the material. Analytical methods used to study minerals have a direct carry-over to the study of synthetic technological products.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Water is of primary importance for not only human and other life, but also for geological processes. A large amount of our planet's water is contained in chemically bound forms in minerals we would normally consider to be anhydrous. Although the concentrations in any individual mineral may be low, the enormous volume of rock within the planet means that the amount of this geologically-held water is potentially comparable to all the water in the Earth's oceans today. Our task has been to understand in which minerals this bound water resides and to develop rigorous, quantitative ways to analyze its concentration.
Towards this objective, we have been comparing analyses obtained by infrared spectroscopy, a method of choice in the past, with a newer method based on a technique known as secondary-ion mass-spectrometry that can measure very low concentrations and work with very small areas of a sample. Over the past two decades, our research group has developed a number of primary standards for the infrared analysis of minerals that are important constituents of the upper mantle of our planet. In the current project, we re-evaluated our existing standards with the new tools to find those best suited as standards at the smaller spatial scales of analysis. We have applied these standards to the new analytical method to develop protocols to optimize the accuracy and reproducibility of the methods. We then used these improved methods to examine a range of minerals that are candidate hosts for small concentration of bound water in a range of minerals.
A primary accomplishment during this grant period has been to establish and publish secondary-ion mass-spectrometry calibrations for minerals groups that are major components of Earth's upper mantle. These include olivines, orthopyroxenes and clinopyroxenes. Large data sets have been obtained on other mineral groups including garnets and feldspars for detailed evaluation and publication in the future.
In addition to the work with bound water in minerals, a significant amount of data has been obtained regarding the incorporation of the fluoride ion in minerals. The fluoride ion is important because, at the atomic level, it can act similarly to the OH- ion, the most important form in which bound water is contained in minerals in Earth's mantle. To understand the detailed incorporation of hydrous components (such as the OH- ion) in minerals, we need to also understand how the fluoride ion participates in these phases and how it might proxy for hydroxide in a way that may initially confuse quantitative relationships between hydroxide (the hydrous component) and other constituents of crystals. During this grant period, our major focus was on the pyroxene minerals which constitute not only an important reservoir of hydrous components in the Earth’s mantle, but also which are an important reservoir for fluorine.
Last Modified: 06/25/2014
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