Microfacies and Sequence Stratigraphy of the Euphrates Formation (Early Miocene) in Heet Area, Western Iraq

Abstract

This study focuses on the Early Miocene Euphrates Formation in two sections (Al-Dulab and Al-Sahiliya), located northwest of Heet City in western Iraq. The thickness of Al-Dulab section is 28.5 meters and 20.2 meters at Al-Sahiliya section. The study identifies three carbonate microfacies types in Al-Dulab section (mudstone, gastropod packstone, peloidal packstone), and six types in Al-Sahiliya section (mudstone, bioclastic wackestone, miliolid peloidal packstone, peloidal packstone, molluscan packstone, bioclastic peloidal packstone). The depositional environment of the Euphrates Formation in the study area ranges from restricted, shoal, to open marine environments. Based on field observations, microfacies analysis, and sequence stratigraphic studies, two fourth-order cycles were identified in Al-Dulab section and four fourth-order cycles in Al-Sahiliya section. These depositional sequences are mostly asymmetrical and represent successive episodes of sea level rises and still stand.