Lithofacies and sedimentary structures studies of Injana Formation in Zakho area, Northern of Iraq

Abstract

The current study of Injana Formation (Late Miocene) at Zakho area, Northern of Iraq. The topic depending mainly of field observations of the outcrop of Injana Formation at the Zakho area. The thickness of formation in Zakho section is about 250m. The formation consists of three major lithofacies: sandstone, mudstone and gravely sandstone. Injana Formation classified to five sublithofacies depending on a description of the physical character such as color, hardness and grain size. These sublithofacies are different in thickness. The study revealed that Injana Formation is represented by eighteen sedimentary cycles which mean a change in deposition environment, these cycles are distinguished fining upwards cycles. Sedimentary structures were observed in the present study such as bedding, channel, cross bedding, ripple marks, graded bedding, traces fossils, mud balls and massive bedding, the recognize the sedimentary structures which leads interpretation the condition of transportation and subenvironments of formation. Finally, we inferred that Injana Formation environments depending on study the sedimentary structures, Lithofacies and sedimentary cycles that Injana Formation was deposited in fluvial environment (meandering rivers), different in their condition of deposition from the base of the formation to the top. large thickness of some beds and without sedimentary structures gives evidence duration of flooding.