The studied area is a part of the Arabian plate located within the High Folded Zone of the Zagros Fold-Thrust Belt in northeastern Iraq (Kurdistan Region). The Study area deals with the Shakrok Anticlines is located between Safin Mountain and Sork Mountain. These structures are formed during the Alpine Orogeny in Cretaceous-Tertiary period. Generally, the folded structures are trending NW-SE direction which is parallel to the main Zagros Orogenic trends.
The exposed stratigraphic succession of the studied area that represented by 4 formations deposited from the Early Cretaceous which are Shiranish, Aqrah, Bekhme and Qamchuqa formations. Shakrok Anticline are asymmetrical, double plunging and verging toward northeast. This establi
... Show MoreThe aim of this study is to investigate the sedimentation environments and diagenetic processes of the Ibrahim Formation (Oligocene-early Miocene) in Zurbatiya, eastern Iraq. The Ibrahim Formation is comprised mostly of clayey micrite and skeletal grains composed of planktonic foraminifera, calcispheres, radiolaria, and benthic foraminifera. Glauconite and pyrite were documented in some restricted zones of this formation; they reflect quiet and reducing conditions. Radiolaria were identified in Late-Oligocene which was not known previously at this age regionally in carbonate formations of the Arabian Plate (AP). Mudstone, wackestone, and planktonic foraminiferal wackepackstone are the main microfacies that are affected by dissolutio
... Show MoreThe Yamama Formation is characterized by a wide geographic extension of southern Iraq. Microfacies analysis of this formation was studied in six wells distributed in six fields: Fayhaa, Sindbad, Siba, Zubair, Ratawi and West Qurna. This research aims to determine paleoenvironments by diagnosing biofacies and lithofacies. Miscellaneous marine fauna of foraminifera and calcareous algae, mainly green algae (dasycladacean.) and skeletal bioclasts from gastropods, pelecypods, bryozoans, sponge spicules, and echinoderms were found. Petrographic studies and well logs interpretations led to the identification of five main Microfacies ( Mudstone, Wackestone, Packestone, Grainestone and Rudstone and twelve submicrofacies (Foraminiferal-
... Show MoreThis study deals with establishing the depositional environment of the Fatha Formation through facies analysis. It also deals with dividing the formation into units based on the rhythmic nature. Data from selected shallow wells near Hit area and deep wells at East Baghdad Oil field are used. Five major lithofacies are recognized in this study, namely, greenish grey marl, limestone, gypsum (and/or anhydrite), halite and reddish brown mudstone (with occasional sandstone).The limestone lithofacies is divided into three microfacies: Gastropods bioclastic wackestone microfacies, Gastropods peloidal bioclastic packstone, and Foraminiferal packstone microfacies.The lithofacies of the Fatha are nested in a rhythmic pattern or what is known as sh
... Show MoreIn the Rumaila oilfields in southern Iraq, the Zubair Formation was deposited in a shallow environment as three main facies, delta plain, backshore, and delta front depositional conditions indicating a transition from delta front and delta plain to a highstand level due to the finning upward mode. The facies of the Zubair clasts show well-sorted quartz arenite sandstone, poorly sorted quartz arenite sandstone, clayey sandstone that has not been properly sorted, sandy shale, and shale lithofacies. The minor lithofacies were identified using well-logging methods (gamma ray, spontaneous potential and sonic logs) and petrography. The Zubair clasts are of transition environment that appears to be transported from freshwater and deposited
... Show MoreCarbonate-clastic succession which includes the Shu'aiba, Nahr Umr and Mauddud formations are representing a part of the Barremian-Aptian Sequence (Wasi'a Group). The present study includes three boreholes (Ba-1, 4 and 8) within the Balad Oil Field. The study area is located in central Iraq. This field represents a subsurface anticline with a northwest to southeast direction axis within the Mesopotamian Zone. Eight types of microfacies were recognized in the succession of the Mauddud and Shu’aiba formations. These microfacies represent shallow open marine, restricted and semi-restricted, reef - back reef, deep open marine and basinal depositional environments. While Nahr Umr Formation includes two successions, the first is the upp
... Show MorePetrographic, heavy mineral and clay mineral analyses are carried out for the sandstone and the mudstone units of Injana and Mukdadiya Formations in Zorbatiya area, Wasit Governorate, East of Iraq. The sandstones and the mudstones are nested as repeated fining–upwards successions, representing fluvial deposits. The sandstones of the Mukdadiya Formation is gravelly and on occasions becomes conglomerate. The sandstone of both formations comprises rock fragments, quartz and feldspars. The rock fragments are the dominant component consisting sedimentary, igneous and metamorphic rock fragments, accordingly these sandstone are classified as litharenite. The clay minerals of the mudstone u
... Show MoreThe Shiranish Formation is cropped out in several areas in northern Iraq. A stratigraphic and facies study was conducted within the Duhok region to determine the sedimentary environment. Three microfacies, reflecting the various subenvironments within different shelf parts of the deep sea, have been identified within the Shiranish Formation. Four depositional environments are identified: slope, the toe of slope, deep shelf, and deep-sea or cratonic deep basin. The Shiranish Formation in the Duhok region, Northern Iraq, was deposited in an open shelf carbonate platform. The Shiranish Formation sequence is divided into six third-order cycles in the study area. These asymmetrical cycles reflect an imbalance between the relative level of the
... Show MoreThe core interval at the K.H5\6 and K.H5\8 Wells in the West of Rutba provinces reveals a significant succession across the Late Cretaceous–Early Paleocene transition. The sampled interval encompasses a series of carbonates belonging to Digma Formation of Latest Cretaceous age, which underlies the Akashat Formtion of Danian age. Fifty-five species belonging to thirty-five genera were recognized. Based on the distribution of these species, eight biozones were distinguished, three biozones are recorded from the K.H 5\6 studied section and two biozones are documented from the K.H 5\8 studied section which refers to Late Maastrichtian age of Digma Formation. Five biozones are recorded from Akashat Formation in the K.H 5\6 studied section and
... Show MoreGlobal oceanic anoxic events (OAEs) are events of immense importance for a variety of reasons. For instance, they are not only behind most if not all of the mass extinctions which took place during the Cenozoic era, but they are the harbinger for the world's best oil source beds, which humanity depends on to satisfy its energy need. In spite of this, there was little effort to document their presence in Iraq, to fill in for the void here, and as a first step, this paper will attempt to establish a cause and effect relationship between OAE 2 and the Gulneri Formation timing of deposition and organic matter richness. This was done by showing the prevalent occurrence of the globally known OAE 2 positive ∂13Corg excursion and the unique ro
... Show More