Universidade Fernando Pessoa

Porto, Portugal

Basic Principles in Foredeep & Foldbelt Basins

VI- Dimensions of a Foredeep Basin

The dimensions of a foredeep basin are largely controlled by the age of the lithosphere (elastic thickness) and the tectonic loading (fig. 11). For this reason, there is a range of dimensions among these basins. Letouzey (1991) suggested that where the lithosphere is young, the width of the basin rarely reaches 50 km (12).

(12) The width of  a foredeep basin is the distance between the peripheral bulge and the outcropping frontal thrust.

Fig. 11- The thickness and the lateral extension of a foredeep basin depend on the age of the lithosphere and the magnitude of the thrust/fold loading.

The thickness of fill is directly related to the tectonic loading. A greater load creates a deeper basin (the length of the basin is more or less constant).

When the elastic thickness of the lithosphere is greater, i.e. when the lithosphere is older, the width of the foredeep is greater. It can reach more than 300 km. In such a particular case, the thickness of the basin fill is mainly dependent on the tectonic subsidence.  

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