EN
Orientation and rounding of limestone coarse grains (5-20 cm) were analyzed in 4 cross sectionts of the middle part of the Wadi Gabes in SE Tunisia. The measured grains were found in the channel floor and banks. It was found that there is an increase in rounding of all measured fractions along the researched part of the wadi. Rounding of fraction 7-10 cm increased the most. Orientation of elongated pebbles were differentiated according to their size. Small pebbles (5-7 cm) were oriented chaotically. Largest pebbles were usually oriented transverse to the wadi channel, which is a result of the rapid deposition from the transportation phase. In the stream current zone apart prevailing transverse orientation the same coarse grains (10-30%) were also imbricated. Orientation and rounding of coarse grains can be used in reconstruction of episodic channels dynamics. Size of the grains that were best rounded and oriented mostly transverse indicate a minimal fraction transported by traction and only sporadically transported in saltation.