| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | July 2, 2019 |
| Latest Amendment Date: | November 15, 2019 |
| Award Number: | 1926096 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Jennifer Wade
jwade@nsf.gov (703)292-4739 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2019 |
| End Date: | August 31, 2022 (Estimated) |
| Total Intended Award Amount: | $263,796.00 |
| Total Awarded Amount to Date: | $263,796.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1500 ILLINOIS ST GOLDEN CO US 80401-1887 (303)273-3000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1500 Illinois Street Golden CO US 80401-1887 |
| 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): |
Tectonics, Petrology and Geochemistry |
| 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
The geological processes that form broad, high-elevation plateaus in otherwise stable and low-lying continental interiors are poorly understood. Yet, such uplift can have profound effects on many aspects of the whole earth system, including atmospheric circulation and biodiversity. Ultimately, the causes of plateau uplift are driven by deep-seated processes within the Earth's crust and lithosphere, but due to inaccessibility, such processes remain enigmatic. A recently proposed hypothesis suggests that the addition of hydrous fluids and/or water to nominally dry lower crust could cause mineral reactions that result in significant changes in density and volume, leading to expansion and therefore surface uplift. However, the magnitude of these changes as functions of rock composition, proportion of fluid added, and depth below the Earth's surface are unquantified. The proposed study addresses this knowledge gap by performing laboratory analysis on rocks collected from the Colorado Plateau, USA, and computational modeling to produce a new predictive toolbox that can constrain the topographic effects of crustal hydration in any geological scenario worldwide. This research will train one new PhD student, two undergraduate students from underrepresented backgrounds, and promote new collaboration between two US-based early-career researchers.
The tectonic effects of crustal hydration are poorly understood, owing to the absence of realistic modeling frameworks for quantifying the petrophysical effects of fluid-rock interaction at middle- to lower-crustal metamorphic conditions. This research aims to directly address this issue by employing recently developed algorithms that quantify the evolution of open and closed petrological systems using equilibrium thermodynamics. Both 1-D and 2-D algorithms will be produced that quantify the relationships between pressure, temperature, bulk-rock density, hydration state, and surface uplift, which can be applied to any crustal environment where fluid-rock interaction takes place. This will also address both closed- and open-system geological scenarios, considering small-scale and short-term fluid influx (e.g. crystallizing magmas) to large-scale, continuous fluid influx (e.g. devolatilization of a subducting slab). Predictions made for intercontinental plateau formation will be ground-truthed by measuring mineral compositions and water contents within natural samples exposed from different levels of the Colorado Plateau crust, as determined by electron probe microanalysis, electron backscatter diffraction, and secondary ion mass spectrometry. The results of this work will assist in deciphering the driving force for its uplift during the Cenozoic and the extent to which fluids released from the subducted Farallon slab were partitioned between the intermediate lithospheric mantle and the lower/middle continental crust.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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.
This project examined the role of hydrous fluids, such as water, in uplifting the deep continental crust. While most areas of high elevation can be explained by plate tectonics, others occur far from plate boundaries. One well-known example is the Colorado Plateau in the southwestern USA. Several tens of millions of years ago, the Colorado Plateau was potentially modified by a widespread piece of buoyant oceanic crust that plowed beneath the North American continent. We test the idea that fluids driven off of this oceanic crust made their way into the deep Colorado Plateau crust, and contributed to several km of uplift that is observed today.
A postdoctoral researcher was supported through this grant. The postdoc conducted computer models of fluid interaction with the crust. These models use information about chemical and mineral reactions to determine whether hydrous minerals can form at certain depths and temperatures. The major conclusion of this work is that fluid interaction can account for about half of the present-day observed surface elevation of the Colorado Plateau.
Broader impacts of this award include PI Chin, a minority female scientist, receiving tenure during the award duration. In addition, PI Palin mentored the postdoc throughout the project, much of which occurred during the COVID-19 pandemic. This was achieved via regular virtual meetings.
Last Modified: 03/16/2023
Modified by: Yvette Kuiper
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