| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | April 28, 2014 |
| Latest Amendment Date: | April 28, 2014 |
| Award Number: | 1345125 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Eva Zanzerkia
EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | May 1, 2014 |
| End Date: | April 30, 2018 (Estimated) |
| Total Intended Award Amount: | $79,958.00 |
| Total Awarded Amount to Date: | $79,958.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1500 SW JEFFERSON AVE CORVALLIS OR US 97331-8655 (541)737-4933 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
104 CEOAS Admin Building Corvallis OR US 97331-5503 |
| 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): | Geophysics |
| Primary Program Source: |
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| 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
Paleomagnetic data play an important role in a variety of geophysical studies of the Earth, including plate tectonic reconstructions, magnetostratigraphy, and studies of the behavior of the ancient geomagnetic field (which we call paleo-geomagnetism). Ever since its inception, the key assumption in many paleomagnetic studies has been that the average direction of the paleomagnetic field corresponds to one that would have been produced by a geocentric axial dipole (GAD), and that the dip of the magnetic field from the horizontal plane provides data of sufficient accuracy to enable their use in plate reconstructions. This proposal will enhance the underlying data that go into time averaged field models, which assess the degree to which the geomagnetic field can be considered "GAD". What is required are data sets with more than 100 sampling sites from all over the globe. To be of most value the data sets would have both directional and intensity data and have excellent age control. The quality required for meaningful interpretation of the data mean that there are very few places on Earth that have adequate coverage. The task at hand is daunting and must be attacked one study at a time. We propose here to exploit the potential of the volcanic fields of Israel, for which there is an enormous amount of preliminary data in the form of both paleomagnetic directions and K-Ar and 40Ar/39Ar dates.
This proposal concerns the understanding of one of the most important physical properties of planet Earth, its magnetic field. Magnetic fields are vectors with both direction and strength. While obtaining ancient field directions is relatively straight-forward, extracting accurate ancient field strength information is not. We propose here to attempt to obtain the full vector information and couple it with accurate age information for a 4-D look at the ancient magnetic field as recorded in the volcanics of Israel. This work can contribute to the understanding of many fundamental processes, including the motions of tectonic plates, the role of the inner core in controlling the geomagnetic field, and establishing the average strength of the magnetic field to place recent observations in perspective. Constraints on the geomagnetic field are important to those who study the dynamical processes in Earth?s deep interior. Also, it will serve as the doctoral dissertation project of a graduate student.
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PROJECT OUTCOMES REPORT
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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.
Paleomagnetic data play an important role in a variety of geophysical studies of the Earth, including plate tectonic reconstructions, magnetostratigraphy, and studies of the behavior of the ancient geomagnetic field. Key assumptions in many paleomagnetic studies are that the average direction of the paleomagnetic field corresponds to one that would have been produced by a simple geocentric axial dipole and that paleoinclinations provide data of sufficient accuracy to enable their use in plate reconstructions. One of the key predictions is that the intensity of the magnetic field doubles from the equator to the poles. However, recent data compilations of high quality paleomagnetic data demonstrates that no such simple geomagnetic field model can account for the existing data. In fact existing paleointensity data do not show the doubling of intensity from equator to pole. In addition, computer simulations suggest that over 100 individual readings of the ancient field in any one location are required to fully characterize paleosecular variation. Only three locations so far on Earth have that many directional measurements (inclination and declination) and even fewer than three have that many paleointensity determinations. With this project we are adding a new location, in the northwest part of the Harrat Ash Shaam volcanic field in the Golan Heights, where volcanism was active between 0.7 and 5.5 million years ago. At the Oregon State University Argon Geochronology Laboratory we have successfully dated 18 Golan Height volcanic samples, with ages ranging between 104,000 of years and 2.6 million years old. The precision and reproducibilities are exclllent, with only uncertainties between 2 and 14 thousands of years at the 95% confidence level. These ages provide the the historical backdrop to place the paleointensity measurements carried by our collaborators from the Scripss Institution of Oceanography.
Last Modified: 07/26/2018
Modified by: Anthony Koppers
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