Causes of Silicification, Tension Joints and Different Degrees and Directions of Dips of Nubian Sandstones Outcrops in Khartoum State Omer

Abstract

Nubian Sandstone outcrops north of Khartoum State are arenaceous with fossils and horizontal, while in central and south are ferruginous, argillaceous, dipping in different directions, with tension joints and no fossils. Field work targeted all outcrops in the study area; methods include description, measurements, and petrographic analysis. The present work referred silicification and Petrified wood formed as a result of hydrothermal alteration by silica derived from adjacent basement complex.Different directions of dips and tension joints is attributed to intrusion of Late Tertiary basaltic rocks in central area.