Geometry and genetics of joints in bahshiqa area.

Abstract

Two main sets of joints were found in pila spi, alfatha, and injana formation in bahsiqa area.- These sets are ac & BC joints. Joints system were also found but in minor amount. The paleostress δ1 which was responsible for the formation of AC and hko acute about A joints, was trending north – south before and during the formation of the major anticline (from middle Eocene – pre- Pliocene). The bc type of joints was formed during the fold formation by two mechanism types ( hinge deformation and limp deformation). In these two mechanism, the axis δ1 was trended northeast – southwest and north – south respectively. At the pre – folding time the hko acute about b developed to form subsurface strike slip displacements which influenced the geometry of bahsiqa anticline.