HR: 0830h
AN: T51F-0213    [PDF]
TI: Elastic Thickness of the lithosphere below the Tehuantepec ridge
AU: * Manea, M
EM: mary@ollin.igeofcu.unam.mx
AF: Dept. Seismology/Inst. Geophysics/UNAM, Ciudad Universitaria, Circuito Inv. Cient, Mexico, df 04510 Mexico
AU: Manea, V
EM: vlady@ollin.geofcu.unam.mx
AF: Dept. Seismology/Inst. Geophysics/UNAM, Ciudad Universitaria, Circuito Inv. Cient, Mexico, df 04510 Mexico
AU: Kostoglodov, V
EM: vladimir@ollin.igeofcu.unam.mx
AF: Dept. Seismology/Inst. Geophysics/UNAM, Ciudad Universitaria, Circuito Inv. Cient, Mexico, df 04510 Mexico
AB: 7 shipborne bathymetry and free-air gravity profiles, crossing the Tehuantepec ridge and fracture zone (TR), have been used to estimate the elastic thickness (Te) of the oceanic lithosphere, by the means of the admittance technique. The age of the oceanic lithosphere and the bathymetry in the vicinity of the TR change abruptly from the NW to SE. The assessment of the age of the lithosphere at the time of bathymetric loading of the TR can be deduced from the analysis of the experimental admittance and the elastic thickness Te. We have computed the admittance, which is interpreted in terms of isotropic elastic plate thickness. A model with a Te of 10$\pm$5 km fits well the observed admittance. The shape of the admittance (low values at low wave-numbers) suggests that TR is isostatically compensated. Using a diagram of the Te versus the age for a cut-off temperature of 450$\deg$C, the age of ~15$\pm$10 Ma was obtained for the oceanic lithosphere at the time of TR onset.
DE: 0920 Gravity methods
DE: 1219 Local gravity anomalies and crustal structure
DE: 3010 Gravity
SC: Tectonophysics [T]
MN: 2003 Fall Meeting