PASSIVE MARGINS AND THEIR SUBSIDENCE

Three main types of subsidence dominate the vertical tectonics of rifted inter-plume passive margins. These are the isostatic response to (1) stretching and thinning of the crust and lithosphere (syn-rift stage), (2) cooling and thickening of the lithosphere (mainly post-rift stage), and (3) sediment loading (both stages). Additionally, vertical movements occur at plume (hot spot) margins as a result of the anomalously hot underlying upper mantle, and emplacement and cooling of magma. Three examples demonstrate various features of subsidence at inter-plume passive margins. -from Author