NSF Org:	EAR Division Of Earth Sciences
Awardee:	UTAH STATE UNIVERSITY
Initial Amendment Date:	July 29, 2020
Latest Amendment Date:	July 29, 2020
Award Number:	1955115
Award Instrument:	Standard Grant
Program Manager:	Dena Smith dmsmith@nsf.gov  (703)292-7431 EAR  Division Of Earth Sciences GEO  Directorate For Geosciences
Start Date:	August 1, 2020
End Date:	July 31, 2023 (Estimated)
Total Intended Award Amount:	$154,684.00
Total Awarded Amount to Date:	$154,684.00
Funds Obligated to Date:	FY 2020 = $154,684.00
History of Investigator:	Carol  Dehler (Principal Investigator) chuaria@cc.usu.edu
Awardee Sponsored Research Office:	Utah State University 1000 OLD MAIN HILL LOGAN UT  US  84322-1000 (435)797-1226
Sponsor Congressional District:	01
Primary Place of Performance:	Utah State University 4505 Old Main Hill Logan UT  US  84322-4505
Primary Place of Performance Congressional District:	01
Unique Entity Identifier (UEI):	SPE2YDWHDYU4
Parent UEI:	SPE2YDWHDYU4
NSF Program(s):	Sedimentary Geo & Paleobiology
Primary Program Source:	040100 NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):	9150
Program Element Code(s):	7459
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.050

ABSTRACT

Rocks from the Cambrian Period (539-485 million years ago) contain fossils that reveal the first diversification of animals on Earth. The timing, causes, and impacts of this “Cambrian Explosion” are poorly understood. Yet clues to understanding this event are buried in Cambrian strata that formed as oceans flooded the world’s continents, and coastal environments blanketed the landscape with vast swaths of sand, mud, and fossils. One of the best-preserved records of these events is in the bottom of the Grand Canyon—in a package of sedimentary rocks known as the Tonto Group. Although the Tonto Group has been studied for nearly 150 years, the availability of new techniques makes it time to revisit these classic exposures. This project will decipher how, when, and why these rocks were deposited, and lead to greater understanding of the Cambrian Explosion of life on Earth. The broader impacts of this research include mentoring a suite of post-doctoral, graduate, and undergraduate scholars, including recruiting and training Hispanic and Native American students. Impacts also include outreach and distance learning through the Denver Museum of Nature and Science, to help this research inspire younger audiences, including 4th-12th graders in rural, first-generation, first-nation, inner-city, and culturally diverse settings. Finally, this project will reach many of the six million annual visitors to Grand Canyon National Park through Park programs, exhibits, media, and NSF-sponsored field forums on Grand Canyon geology.

Cambrian rocks record dramatic changes in Earth systems including atmospheric oxygenation events, large magnitude perturbations to the carbon cycle, and the punctuated evolution of animal life. These events played out within the global transgressive inundation of continents by advancing oceans that deposited sheet sands, muds, and carbonates. Underpinning the research plan is a novel, integrative approach to calibrating the timing and tempo of this marine transgression. This approach combines: a) radioisotopic dating of the youngest, penecontemporaneously deposited zircon crystals, which are hidden amidst the detritus making up these sedimentary rocks; b) identifying changes in the types of fossils in the same rocks, and; c) documenting changes in mineral, chemical, and physical signatures of these rocks that record simultaneous, related changes in the Cambrian Earth system—such as changes in sea level or the collision and breakup of continents. Initial work has shown that the Tonto Group of the Grand Canyon is tens of millions of years younger than previously thought, that seas flooded North America relatively quickly, and that other continental margins experienced the same event. The project will expand upon a pilot study that was conducted in the Grand Canyon, and augment it with contemporaneous strata throughout the western U.S. to test hypotheses about how these flooding episodes relate to global biologic, tectonic, and geophysical events and processes.

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.

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