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Temperature‐dependent Newtonian and non‐Newtonian convection: Implications for lithospheric processes
Author(s) -
Larsen Tine B.,
Malevsky Andrei V.,
Yuen David A.,
Smedsmo Jamie L.
Publication year - 1993
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 - 10.1029/93gl02863
Subject(s) - newtonian fluid , rheology , viscosity , non newtonian fluid , geology , lithosphere , mechanics , convection , rayleigh number , thermodynamics , natural convection , physics , geotechnical engineering , seismology , tectonics
Convection studies of temperature‐dependent Newtonian and non‐Newtonian rheology in aspect‐ratio seven boxes have been carried out for volume averaged Rayleigh numbers between O(10 5 ) and O(10 7 ). Large lateral viscosity variations, O(10 4 ) are found for non‐Newtonian cases with total temperature‐dependent viscosity variations up to 250. Flow structures for both rheologies are distinguished by large‐scale circulations with relatively stable descending limbs. Much larger hot thermal anomalies are found near the surface for non‐Newtonian rheology. Lithospheric thinning is facilitated by non‐Newtonian rheology because of stress‐softening and the lubrication of the descending limbs by hot diapirs.