Premium
Variation in lithospheric stress along ridge‐transform plate boundaries
Author(s) -
Blackman Donna K.
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl00122
Subject(s) - geology , lithosphere , seafloor spreading , transform fault , mid ocean ridge , ridge , ridge push , plate tectonics , rift , lithospheric flexure , stress field , seismology , geophysics , geometry , geodesy , tectonics , finite element method , paleontology , physics , mathematics , thermodynamics
Three‐dimensional numerical models of asthenospheric flow and deformation in the oceanic lithosphere predict variability in the stress field that reflects the geometry of the ridge‐transform boundary. A series of 3‐D Boundary Element calculations shows how spreading rate, transform offset and segment length each influence the flow and stress fields that develop during plate‐driven asthenospheric flow beneath a ridge‐transform boundary. The predicted patterns of stress‐supported seafloor relief generally follow those observed: median valleys are predicted at slow‐spreading ridges vs no rift valley or, in some cases, a small axial high at fast spreading ridges; nodal deeps occur at ridge‐transform intersections for offsets greater than 25 km; longer segments have more along‐axis deepening than short segments which do not shoal much in their center. The predicted amplitude of the stress supported topography is up to 20% (across axis) and 40% (along axis) of that observed for an assumed asthenospheric viscosity of 5×10 19 Pa s and a weak lithosphere (local compensation).