Paleostress analysis of the cretaceous rocks in Northern Jordan

Abstract EN

Stress inversion of 747 fault- slip data was performed using an improved Right-Dihedral method, followed by rotational optimization (WINTENSOR Program, Delvaux, 2006).

Fault-slip data including fault planes, striations and sense of movements, are obtained from the quarries of Turonian Wadi As Sir Formation , and distributed over 14 stations in the study area of Northern Jordan.

The orientation of the principal stress axes (σ1, σ2, and σ3 ) and the ratio of the principal stress differences (R) show that σ1 (SHmax) and σ3 (SHmin) are generally sub-horizontal and σ2 is sub-vertical in 9 of 15 paleostress tensors, which are belonging to a major strike-slip system with σ1 swinging around NNW direction.

Four stress tensors show σ2 (SHmax), σ1 vertical and σ3 are NE oriented.

This situation is explained as permutation of stress axes σ1 and σ2 that occur during tectonic events.

The new paleostress results show three paleostress regimes that belong to two main stress fields.

The first is characterized by E-W to WNW-ESE compression and N-S to NNE –SSW extension.

This stress field is associated with the formation of the Syrian Arc fold belt started in the Turonian.

The second paleostress field is characterized by NW-SE to NNW-SSE compression and NE-SW to ENE-WSW extension.

It is related to Middle Miocene – Recent sinistral movement along the Dead Sea transform and the opening of the Red Sea.