Accession Number:

ADA305890

Title:

Tectonics of the East Pacific Rise: Studies of Faulting Characteristics and Magnetic and Gravity Anomalies.

Descriptive Note:

Doctoral thesis,

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s):

Report Date:

1995-02-01

Pagination or Media Count:

517.0

Abstract:

Investigation of Sea Beam bathymetric data collected between 9 deg 10 and 9 deg 50N of the East Pacific Rise suggests that normal faulting may continue to a distance of at least 30 km from the axis. Mechanical models were used to demonstrate that, while buoyancy arising from crustal magma chamber during a stage of a weak rise axis may explain the initiation of normal faults at 2-3 km from the axis, a rise axis with a finite strength is needed to explain their further development off-axis. Variation in the magnetization intensity of the magnetic source layer appears to be the primary cause of a southward increase in the axial magnetization high. A correlation was found between the short-wavelength appox. 5 km magnetization anomalies parallel to the rise axis and short reversal events reported within the Brunhes epoch. The occurrence of marked offsets in the linearity of axial magnetization anomalies and short-wavelength 30 km residual gravity anomaly lows along the axis suggests that the rise axis in this area can be divided into segments of 10-15 km in length, with each segment defined by the locus and timing of most recent emplacement of magma in the axial crust. AN

Subject Categories:

  • Physical and Dynamic Oceanography
  • Geology, Geochemistry and Mineralogy
  • Seismology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE