The present location of the Nubia-Somalia-Antarctica triple junction
Cowles, Sara Marie
Gordon, Richard G.
Master of Arts
I estimated 75 previously unavailable sea-floor spreading rates from shipboard and airplane magnetic profiles. To estimate the location of the Nubia-Somalia-Antarctica triple junction along the Southwest Indian Ridge (SWIR) I combined these, new rates with the 59 rates and 9 transform fault azimuths used by Chu and Gordon (1999). F-ratio tests determined the statistical significance of a two-plate (Africa-Antarctica) model and various three-plate (Nubia-Somalia-Antarctica) models. The best fit Nubia-Antarctica angular velocity is a rotation of 0.1512 +/- 0.0015° Myr-1 (1sigma) about 12.596° N, 44.340° W. The best fit Somalia-Antarctica angular velocity is a rotation of 0.1378 +/- 0.0034° Myr-1 (1sigma) about 14.299° N, 55.064° W. If a narrow Nubia-Somalia boundary intersects the SWIR, the Nubia-Somalia-Antarctica triple junction lies along the SWIR between 36.28° E and 38.50° E (95% confidence limits). The best fit Nubia-Somalia angular velocity is a rotation of 0.0297 +/- 0.0085° Myr-1 (1sigma) about 2.068° S, 12.388° E.
Physical geography; Geophysics