The Evolution of the Indian Ocean Triple Junction and the Finite Rotation Problem.

The three papers of this thesis demonstrate that studies of the stability and evolution of triple junctions and of the finite rotations of systems of three plates can yield significantly more accurate tectonic histories than can studies of relative motions between two plates alone. Topographic and m...

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Bibliographic Details
Main Author: Tapscott,Christopher Robert
Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MASS
Format: Text
Language:English
Published: 1980
Subjects:
Physical and Dynamic Oceanography
Geology
Geochemistry and Mineralogy
*OCEAN RIDGES
*SEAFLOOR SPREADING
*TECTONICS
VELOCITY
INDIA
THESES
CONTINENTAL DRIFT
PLATES
EVOLUTION(GENERAL)
JUNCTIONS
AFRICA
ROTATION
RIGIDITY
INDIAN OCEAN
OCEANIC CRUST
ANTARCTIC REGIONS
GREENLAND
MAGNETIC ANOMALIES
LITHOSPHERE
LABRADOR SEA
Plate tectonics
Triple junctions
Southwest Indian Ridge
WUNR083004
Antarctic
Greenland
Indian
Antarc*
Antarctica
Labrador Sea
Online Access:http://www.dtic.mil/docs/citations/ADA089103
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA089103
Description
Summary:The three papers of this thesis demonstrate that studies of the stability and evolution of triple junctions and of the finite rotations of systems of three plates can yield significantly more accurate tectonic histories than can studies of relative motions between two plates alone. Topographic and magnetic investigation of the Southwest Indian Ridge and reconstruction of the plate system of the Indian Ocean shows that both Africa and Antarctica are rigid plates and their pole of relative rotation has remained fixed near 8 deg N, 42 deg W since the Eocene. A detailed survey of the Indian Ocean triple junction reveals that the Indian Ocean plate motions have remained constant since 10 Ma. Stability conditions of the junctions show that the general morphology of the Southwest Indian Ridge results from the evolution of the Indian Ocean triple junction. A method is presented for determining the finite rotations best reconstructing the past relative positions of three plates around a triple junction. The method is illustrated by reconstructions of the plates around the Labrador Sea triple junction at the times of anomalies 24 (56 Ma) and 21 (50 Ma). Prepared in cooperation with Massachusetts Inst. of Tech., Cambridge. Dept. of Earth and Planetary Sciences, Contract N00014-75-C-0291.

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