Tectonostratigraphy For Upper Cretaceous Southern Iraq

Abstract

The study of the lithoogical columns in 20 oil wells selected from many southern Iraq oil fields proved that these two movements (Second Austrian Alpine and Laramide) affect the diversity, as well as the vertical and lateral sediments distribution in the studied area. Two models were observed for the effect of Episode 2 in the sediments understudy. The first one is direct represented by the lateral and vertical thickness variation. Whereas the second is indirect represented by the changes in sea level and accommodation space, these two factors have great effect on sediments diversity. The intensity of the second Austrian Alpine is greater that of Larimidian movement causing the heterogeneity in the lateral and vertical thickness of Ahmadi, Rumaila and Mishrif formation, and the relative homogeneity in the thickness of Upper Tanuma, Saadi, Hartha, Shiranish, and Tayarat Formations. The sediments of the Second Austrian Movement characterized by their shallowing upward facies except Rumaila Formation which exhibits sub basinal facies due to the relative sea level changes. Furthermore, the Laramidian sediments characterized by deepening upward facies represented by Upper Saadi and Shiranish formations.