| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | July 23, 2012 |
| Latest Amendment Date: | May 16, 2017 |
| Award Number: | 1212754 |
| 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: | July 15, 2012 |
| End Date: | June 30, 2018 (Estimated) |
| Total Intended Award Amount: | $214,025.00 |
| Total Awarded Amount to Date: | $214,025.00 |
| Funds Obligated to Date: |
FY 2013 = $67,496.00 FY 2014 = $70,755.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
5241 BROAD BRANCH RD NW WASHINGTON DC US 20015-1305 (202)387-6400 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
5251 Broad Branch Rd., NW Washington DC US 20015-1305 |
| 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: |
01001314DB NSF RESEARCH & RELATED ACTIVIT 01001415DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Intellectual merits. An experimental study is proposed to advance our understanding the processes that govern the budget and recycling of volatile components in the system C-O-H-N in the Earth?s interior. Relationships between structure and transport, volume, and thermodynamic properties of silicate melts and C-O-H-N fluid and fluid/melt element and stable isotope fractionation will be examined while samples are at temperature, pressure, and redox conditions primarily using a hydrothermal diamond anvil cell (HDAC). Major objectives are to: [1] Use vibrational spectroscopy to characterize structure and properties in silicate-C-O-H-N melt, mineral, and fluid systems as proxies to model the behavior of fluids and melts in natural magmatic systems. [2] Determine fractionation of structural species, and of isotopes between minerals, melts, and fluids in silicate-COHN systems using vibrational spectroscopy and microbeam analyses of quenched materials. [3] Develop structure-property models to explain the behavior of natural magmatic systems at P-T conditions corresponding to the upper mantle of the Earth. Current knowledge of structure of solubility and solution mechanisms of C-O-H-N volatile components in silicate melts is based largely on analytical and structural examination of quenched melts (glasses). However, this information does not precisely reflect properties of actual melts. Conversely, the proposed experiments will enable measurements of samples while they are being held at temperature, pressure and redox conditions representative of the Earth?s upper mantle. Characterization how melt structure affects mineral/melt element partitioning will be addressed by combining melt structural data with trace element partitioning experiments (relying on electron microprobe and ion probe analysis of run products). Partitioning of structural species between melts and fluids will be accomplished with vibrational spectroscopic techniques and will be compared with elemental analyses as a means to calibrate the partitioning of the structural species determined by vibrational spectroscopy. Protocols will also be developed for use of vibrational spectroscopy to determine D/H fractionation between fluid and melt while at desired pressure, temperature, and redox conditions. The proposed work will also provide new information on rheology, compressibility, and thermodynamics of component mixing for magmatic systems (melts and fluids) at deep crust and upper mantle conditions.
Broader Impacts. The PI typically has one high school student and one undergraduate student (funded by the Geophysical Laboratory) working in his laboratory. This will continue as a part of the proposed research. These programs have been very successful resulting, for example, in seven articles in the peer reviewed literature from the work done in the PIs laboratories during the last several years with undergraduate and high school students as co-authors. In this regard, the PI contributes time to judge and supervise projects by middle and high school students. Winners of this fair proceed to national science competitions such as the International Science Fair and the Siemens Foundation's competition in Math-Science-Technology.
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.
The project was aimed to obtain structure and structure-property relationships of silicate-COHN systems at pressures, temperatures, and redox conditions corresponding to those of the Earth's crust and upper mantle. Particular focus was on experiments conducted with the sample under appopriate conditions so that the data required to chararacterize the dynamics of magmatic processes (formation, aggregation, ascent, and emplacement of magmatic liquids and fluids).
Therefore, the experimental work has focused on (i) Characterization of melt and fluid structure at the atomic level with samples at high pressures and temperatures, (ii) on determination of the structural variables needed for quantitative description of melt and fluid properties necessary for characterization of energy and mass transfer, and (iii) on development of models with which to characterize melt and fluid properties on the basis of their structure.
Control of redox conditions was particularly important as results obtained under such circumstances offera means to determine fluid speciation in the C-O-H-N system during the earliest, core-forming stages of the Earth where the main C-O-H fluid species likely were CH4, H2O, NH3 and H2. This information in turn, formed the experimental basis to determine solubility of reduced C-O-O-N volatiles in silicate melts, the solubility of silicate components in such fluids, and stable isotope fractionation between fluids and melts as a function of the energetics of (C-O-H-N) chemical bonding. Further, fH2-dependent solution mechanisms also affect silicate melt structure differently thus causing fH2-dependent thermodynamic and transport properties of magmatic liquids in the interior of the Earth and terrestrial planets.
Methods were also developed with which stable isotpe fractionation could be determined in-situ. The results are of particular importance in the use of light isotope behavior as a means of deducing magmatic processes and melt/rock interactions in the Earth's interior. The data are also particularly relevant to our understand of how volatile components have been, and remain, recycled in the Earth.
Last Modified: 07/02/2018
Modified by: Bjorn O Mysen
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