FN Archimer Export Format
PT J
TI Passive Margin Development. A Consequence of Specific Convection Patterns in a Variable Viscosity Upper Mantle
BT 
AF MEISSNER, R
AS 1:;
FF 1:;
IF 0.662
TC 0
UR https://archimer.ifremer.fr/doc/00245/35658/34167.pdf
LA English
DT Article
AB Simple thermodynamics calculations are applied to processes of a rising plume within an environment of an upward directed gradient of viscosity in the uppermost mantle. Four stages of the development of passive margins are described. Following an initial regional uplift strong lateral movements are induced at asthenospheric levels, stretching the overlying lithosphere. In the second stage plume material also enters the low viscosity lower crust, replacing continental material and forming a new, higher crust-mantle boundary by gravitational differentiation. The inital phase lag between the laterally intruding plume material and the rest of the lithosphere disappears once the continent is rifted and sea floor spreading is established (= stage 3). Finally, at stage 4, quiet subsidence, controlled by contraction, sedimentation, and possible phase changes in the lower crust, is established. The sequence described is in accordance with many observations of geology and geophysics. Rising plumes and sinking slabs are considered equivalent expressions of the heat engine earth which determines global tectonics.
PY 1981
SO Oceanologica Acta, Special issue
SN 0399-1784
PU Gauthier-Villars
ID 35658
ER

EF