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Effect of near‐ridge thermal anomalies on the subsidence of the oceanic lithosphere: Constraints from a 2‐D dynamic model
Author(s) -
Chiao LingYun,
Wang ChiWei
Publication year - 1999
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 - 10.1029/1999gl900098
Subject(s) - asthenosphere , lithosphere , geology , mantle (geology) , ridge , subsidence , ridge push , thermal subsidence , mid ocean ridge , geophysics , lithospheric flexure , thermal , temperature gradient , petrology , seismology , geomorphology , tectonics , paleontology , meteorology , physics , structural basin
A 2‐D dynamic cooling model with temperature‐dependent asthenosphere viscosity is devised to examine the impact of near‐ridge thermal anomalies on the subsidence of the oceanic lithosphere. In this model, mid‐ocean ridge segments with cooler than ambient mantle temperatures have calculated subsidence rates that cannot be differentiated from normal ridge segments. This occurs because the cooler thermal anomaly cannot be sustained, nor can it spread off‐axis, due to thermally driven near‐ridge buoyant flow. When the cooler anomaly is deeply rooted, this buoyant flow can be inhibited only when the asthenosphere viscosity is as high as 3×10 20 Pa‐s. On the other hand, ridge segments with warmer mantle temperatures have significantly higher subsidence rates than those predicted from standard conductive cooling models. Simply varying the injection temperature invalidates the 1‐D simplification usually invoked implicitly in models of the cooling process of the oceanic lithosphere.