South American-Antarctic plate motion over the past 50 Myr, and the evolution of the South American-Antarctic ridge
Abstract
Magnetic and bathymetric data from the South American-Antarctic plate boundary east of the South Sandwich trench have been analyzed in order to determine ocean floor ages, spreading rates, and directions. It is found that South American-Antarctic plate motion over the past 50 Myr has been only 10-15 mm/yr (half rates), and that at about 20 Ma the spreading direction changed from 120-300 deg to the present E-W. It is suggested that the global balance of forces may for long periods be imperfectly reflected in plate motions, and that the causes of the abrupt changes in direction may precede the changes themselves by several million years.
- Publication:
-
Geophysical Journal International
- Pub Date:
- September 1988
- DOI:
- 10.1111/j.1365-246X.1988.tb02261.x
- Bibcode:
- 1988GeoJI..94..377B
- Keywords:
-
- Planetary Evolution;
- Plates (Tectonics);
- Ridges;
- Structural Properties (Geology);
- Antarctic Regions;
- Bathymeters;
- Earthquakes;
- Magnetic Anomalies;
- Maps;
- South America