Restricted Research - Award List, Note/Discussion Page

Fiscal Year: 2021

325  The University of Texas Rio Grande Valley  (84621)

Principal Investigator: Harrison, Cheryl

Total Amount of Contract, Award, or Gift (Annual before 2011): $ 453,227

Exceeds $250,000 (Is it flagged?): Yes

Start and End Dates: 9/15/20 - 8/31/23

Restricted Research: YES

Academic Discipline: N/A

Department, Center, School, or Institute: Sch of Earth Env & Marine Sci

Title of Contract, Award, or Gift: Collaborative Research: Evaluating Climate Change and Kill Mechanisms Associated with the End-Cretaceous Mass Extinction: A Model-Data Comparison Approach

Name of Granting or Contracting Agency/Entity: National Science Foundation

Program Title: NSF 20-509 Frontier Research in Earth Sciences
CFDA Linked: Geosciences


Paleontological evidence confirms that ~75% of all species on Earth went extinct across the Cretaceous-Paleogene (K-Pg; 66 Ma) boundary. Although most experts agree that the K-Pg mass extinction was a result of the Chicxulub impact, associated forcings and feedbacks have largely been approached qualitatively, limiting mechanistic understanding of the causes for extinction. Moreover, existing proxy data do not constrain environmental changes well during the first years to millennia of the Paleogene. With a diverse team of researchers, the proposed study will combine proxy records with Earth system model simulations to elucidate the processes leading to the K-Pg extinction and subsequent environmental recovery. Using a state-of-the-art Earth system model, the PIs propose K-Pg simulations that mimic forcings from the Chicxulub impact. The model contains an explicit aerosol resolving scheme and high-top atmosphere, both essential for capturing the processes associated with these perturbations. Further, development and implementation of an ocean biogeochemistry module will allow for direct comparison with paleontological, chemical, and isotopic records across the K-Pg boundary. These simulations will capture the temporal and spatial responses of the earth system from the first day to 50-kyr post-impact. The proposed experiments will be the first to simulate the coupled responses of Earth's climatological, depositional, and biotic systems to these K-Pg events within a consistent modeling framework. To constrain and validate the K-Pg simulations, the PIs will collect high resolution soot, temperature, and biomarker records. Studies suggest that if the impact produced widespread fires, then soot emission could drive an impact winter. However, evidence for fires remains controversial. Therefore, additional samples will be analyzed for soot and polycyclic aromatic hydrocarbons to test the fires hypothesis and provide additional constraints for the simulations. Further, proxy records of the first 1 to 100,000 years after impact vary considerably among studies. The PIs propose generating new estimates for temperature change using phosphatic microfossils, a paleotemperature archive widely used with Paleozoic samples, but previously applied to the K-Pg only once with provocative results, and TEX86, a paleotemperature archive previously shown to capture abrupt climate change after the K-Pg boundary. These records will provide sub-millennial to millennial scale constraints on temperature, and in combination with simulations and new soot estimates, a means to backout CO2 emission associated with the impact. Finally, high resolution biomarker work will shed light on the rate of marine planktonic recovery and discrepancies between organic and inorganic carbon isotope records after the impact, which will be directly compared with the ocean biogeochemistry simulations to produce a mechanistic understanding. SAMs 1.1.1

Discussion: No discussion notes


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