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On global gravity anomalies and two-scale mantle convectionThe two-scale model of mantle convection developed by Richter and Parsons (1975) predicts that if the depth of the convective layer is about 600 km, then for a plate moving at 10 cm/yr, longitudinal convective rolls will be produced in about 50 million years, and the strike of these rolls indicates the direction of motion of the plate relative to the upper mantle. The paper tests these predictions by examining a new global free air gravity model complete to the 30th degree and order. The free air gravity map developed shows a series of linear positive and negative anomalies (with transverse wavelengths of about 2000 km) spanning the Pacific Ocean, crossing the Pacific rise and striking parallel to the Hawaiian seamounts. It is suggested that the pattern of these anomalies may indicate the presence of longitudinal convective rolls beneath the Pacific plates, a result which tends to support the predictions of Richter and Parsons.
Document ID
19770029046
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Marsh, B. D.
(Johns Hopkins University Baltimore, Md., United States)
Marsh, J. G.
(NASA Goddard Space Flight Center Geodynamics Branch, Greenbelt, Md., United States)
Date Acquired
August 8, 2013
Publication Date
October 10, 1976
Publication Information
Publication: Journal of Geophysical Research
Volume: 81
Subject Category
Geophysics
Accession Number
77A11898
Funding Number(s)
CONTRACT_GRANT: NSG-5090
CONTRACT_GRANT: NSF DES-75-18451
Distribution Limits
Public
Copyright
Other

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