The Large-Scale and Long-Term Dynamics of Subduction
{'Code': '06030204', 'Directorate': {'Abbreviation': 'GEO', 'LongName': 'Directorate For Geosciences'}, 'Division': {'Abbreviation': 'EAR', 'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'Michael A. Mayhew', 'PO_EMAI': None, 'PO_PHON': None}
The research addresses the relationship between observations               of mantle heterogeneity and the history of subduction for about                 the last 200 Myr.  This work requires coordinated efforts in two                fields, namely, theoretical geodynamics and global tectonics.                   Subducted slabs constitute the largest known density constrasts in              the mantle.  The largest-scale seismic velocity and geoid                       anomalies are not correlated with present-day plate tectonics, but              are qualitatively similar to older (100-200 Myr B.P.)                           configurations of subduction.  This suggests that the large-scale               pattern of mantle convection is dominated by the long-term                      patterns of subduction.  The project will test this hypothesis                  quantitatively for various convection models.  Previous mapping of              Pacific Basin convergency zones (0-180 Myr B.P.) will be expanded               to include other important paleosubduction zones in the Indian                  Ocean Basin and elsewhere.  Subducted plate ages, rates, and                    locations will be converted into a corresponding map for the                    injection of thermal buoyancy into the upper mantle.  The                       trajectories of slabs due to mantle flow will be calculated using               a well-developed analytical method for flow in spherical shells.                Both chemically layered and viscosity layered convection models                 driven subducted buoyancy forces will be explored.  These                       dynamical models for the fate of old subducted slabs will be                    rigorously correlated with observations bearing on density                      contrasts in the mantle, particularly the new observations of                   seismic heterogeneity, the gravity field, and plate velocities.                 By integrating knowledge of plate tectonic history with present-                day geophysical observations and convection theory, this work will              provide entirely new constraints on the large-scale nature of                   mantle convection.
{'FirstName': 'Mark', 'LastName': 'Richards', 'PI_MID_INIT': 'A', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Mark A Richards', 'EmailAddress': 'markrich@uw.edu', 'NSF_ID': '000367645', 'StartDate': '06/01/1988', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of Oregon Eugene', 'CityName': 'EUGENE', 'ZipCode': '974031905', 'PhoneNumber': '5413465131', 'StreetAddress': '1776 E 13TH AVE', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'Oregon', 'StateCode': 'OR', 'CONGRESSDISTRICT': '04', 'CONGRESS_DISTRICT_ORG': 'OR04', 'ORG_UEI_NUM': 'Z3FGN9MF92U2', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF OREGON', 'ORG_PRNT_UEI_NUM': 'Z3FGN9MF92U2'}
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{'Code': '1574', 'Text': 'Geophysics'}
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8718500.xml'}