Universidade Fernando Pessoa

Porto, Portugal

Basic Principles in Foredeep & Foldbelt Basins

IX- Evolution of a Foredeep Basin

When the tectonic loading is in sequence, the evolution of a foredeep basin can be illustrated as shown in fig. 14.

Fig. 14- Foredeep basins apparently do not have a thermally induced driving component, although both the sediments and basement may heat up as subsidence and thrust load migration proceeds. The movement of the basin is produced by flexure due either to thrust and fold loads emplacement on the surface of the crust or to "buried loads" within the adjacent orogenic belts.

In such an evolution, it is important to note:

a) The progressive displacement of the flexural bulge toward the craton,

b) The formation and displacement of the  “piggy-back basins”, which are localized backward of each thrust complex.

c) That which each new tectonic loading, there is formation of:

 (i) A new foredeep basin in front of the frontal thrust and

 (ii) A new “piggy-back” basin” behind the frontal thrust. 

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