development of the great escarpments & the fall line on passive plate margins on the basis of conceptual model of passive margin denudation & shoulder uplift

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Passive margin or Atlantic type margin has 3 main topographic & structural features:-
1)a marginal bulge falling into the sea or bound by a great escarpment;
2)a broad crustal plain or low plateau;or
3)a complex block of basins.


Distinctive landforms of passive margins are great escarpments which are extraordinary topographic features.A great escarpment often separates a soft relief from highly dissected relief beyond escarpment foot.Not all passive margins bear great escarpments.Some passive margins that lack great escarpments do posses low marginal upwarps flanked by significant break of slope.

A fall line is a line or a zone marking the tract where a series of almost parallel rivers descend from a mountain region or a plateau edge on to the lowland by means of waterfalls.In the eastern U.S.A. the fall line marks the belt along which some of the Appalachian rivers leave the older folded rocks & debauch on to the younger sedimentary rocks of coastal plain.

The formation of great escarpments & fall line is possible on that passive plate margin having possible on that passive plate margin having a marginal bulge or a low plateau.The upwarping causes increasing height of relief while backwearing increases slope gradient encouraging waterfalls.The great escarpment of western ghats is caused by the process if scarp recession by backwearing & shoulder upliftment by upwarping due to tectonic forces.

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