Facies Characteristics, Depositional Environments and Sequences Stratigraphy of the Euphrates Formation in Hadetha Area, Western Iraq

Abstract

The Euphrates Formation (Lower-early middle Miocene) shallow water carbonates, western Iraq was studied in order to determine its microfacies and depositional environment. According to the benthic foraminiferal assemblage along with other skeletal and non-skeletal components, Fourteen microfacies associations types (F1-F14) are recorded and distributed as: Lime mudstone, miliolids wackestone, alveolinids wackestone, echinoids wackestone, bioclastic packstone, peliods packstone, miliolids packstone, peneroplids packstone, rotaliids packstone, miliolids grainstone, peliods grainstone, ooids grainstone, miliolids-peneroplids grainstone, and peneroplids grainstone that were deposited in three facies belts, restricted marine, shoal, and open marine environments. Based on field observations, microfacies analysis and sequence stratigraphic concepts, the Lower Miocene successions is represented by four order cycles (A, B, C and D) they are mostly asymmetrical showing slightly lateral variation in thickness and symmetry. These cycles represent a succession episode of sea level rises and stillstands. The nature of these cycles reflects variation in the relative sea level resulted from eustatic and tectonic subsidence. Cycle A is underlain by Anah Formation, while cycle C is overlain by SB1 Fatha Formation. According to sequence development, the study area shows low rate of subsidence and the major controlling factor that effect is eustatic sea level fluctuation.

Microfacies and depositional environment of Tarbur Formation (Upper Cretaceous‐Lower Palaeocene) Zagros area, southwestern Iran

“…However, the textural characteristic of this microfacies represents floatstone ‐packstone. This microfacies is referred to shallow water parts of a lagoon (Afghah, 2016; Al‐Ghreri, Al‐Gibouri, & Al‐Heety, 2015; Anari, Kohansal Ghadimvand, Kangazian, & Hejazi, 2015; Rahmani, Vaziri‐Moghaddam, & Taheri, 2010). The rudist‐miliolid‐intraclast packstone microfacies is distributed in the upper part of Dariyan, Zarghan, Kuh‐e Khanehkat, Kherameh‐1 and Kherameh‐2 sections.…”

Microfacies Analysis and Paleoenvironment of Baba Formation, Anah Area Westren Iraq

“… The presence of large size of Lepidocyclina with packstone texture within this formation was evidenced of sedimentation in fore-reef environment [23].  The occurrence of Nummulites within Baba Formation was indicated of relatively deep sitting to move away from high light and to preserve its test from the high kinetic energy of currents and sea waves [24].  The presence of Miliolids within this formation explains that deposition occurred within shallow environment with limited circulation of water movement [25].…”

“… It also explained the existence of the Corall Lime Boundstone to warm, shallow sitting and normal salinity during the Oligocene period, and it was deposited in the coral reef environment [22].  The presence of large size of Lepidocyclina with packstone texture within this formation was evidenced of sedimentation in fore-reef environment [23].  The occurrence of Nummulites within Baba Formation was indicated of relatively deep sitting to move away from high light and to preserve its test from the high kinetic energy of currents and sea waves [24].…”

A Stratigraphic Development of the Upper Oligocene - Middle Miocene succession in Wadi Heglan, Western Iraq

“…Interpretation: this facies is deposited in shallow marine to represent a lagoon/back-reef (inner ramp) environment [17], as indicated of low energy restricted/lagoon setting [18], and it is indicator of low diversity skeletal fauna. Stated the miliolids present in shallow marine water of barrier-reef setting.…”