scholarly journals Petrography And Diagenetic History Of The Kometan Formation (Upper Cretaceous) In The Imbricated Zone, Iraqi Kurdistan Region

2020 ◽  
Vol 70 (1) ◽  
pp. 195-208
Author(s):  
Irfan Sh. Asaad ◽  
◽  
Sardar M. Balaky ◽  
Keyword(s):  
Upper Cretaceous ◽  
Planktonic Foraminifera ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Iraqi Kurdistan ◽  
Diagenetic Processes ◽  
History Of ◽  
Diagenetic History ◽  
Petrographic Study ◽  
Late Stages

The petrography and diagenetic history of Upper Cretaceous Kometan Formation is investigated from its type locality in Kometan Village, Imbricated Zone, Kurdistan Region, Northeastern Iraq. The formation comprised 44 m of white weathered, light grey, thin to medium bedded fractured limestones with chert nodules and lenses in the upper part. The petrographic study of the formation is based on 50 thin sections and showed that the majority of limestones microfacies are carbonate mud (micrite). The skeletal grains include planktonic foraminifera, oligostegina, calcisphers, ostracods, pelecypods, larvae ammonoids and echinoderms. Non-skeletal grains include peloids only. The Kometan Formation has been subjected to several diagenetic processes such as: micritization, dolomitization, cementation, neomorphism, compaction, silicification, solution, phosphatization, glauconitization and fracturing. All these occurred during marine phreatic shallow burial stage and activated during intermediate to deep burial and uplifting in the late stages. The paragenetic history of the Kometan Formation has passed through four diagenetic environments including; marine, meteoric, burial and uplifting.

scholarly journals Bone microstructure and diagenesis of saurischian dinosaurs from the Upper Cretaceous (Neuquén Group), Argentina

2017 ◽  
Vol 44 (1) ◽  
pp. 39 ◽  
Author(s):  
Elena Previtera
Keyword(s):  
Upper Cretaceous ◽  
Bone Microstructure ◽  
Depositional Environments ◽  
Integral Approach ◽  
Burial History ◽  
Thin Sections ◽  
Diagenetic Processes ◽  
History Of ◽  
Diagenetic History ◽  
Fluvial Environments

The Neuquén Basin in northwestern Patagonia, Argentina, holds the most important record of Cretaceous dinosaurs in South America.The Neuquén Group (Upper Cretaceous) is the richest dinosaur-bearing unit of the basin. It comprises the Río Limay, the Río Neuquén and the Río Colorado subgroups. In this study, dinosaur remains from the Río Neuquén and the Río Colorado subgroups outcropping in Mendoza are examined. In this group, isolated, disarticulated or partially articulated sauropods and theropods are abundant. However, little is known about the diagenetic history of fossil assemblages. In southern Mendoza, three fossiliferous sites were found in the areas of Paso de las Bardas (Quebrada Norte) and Cerro Guillermo (CG1, CG2). This study aims to add to the knowledge of diagenetic processes involving dinosaur remains from the Neuquén Group, as well as their relation to the depositional environment. Histologic features and diagenetic processes of dinosaur bones were analyzed through thin sections in order to interpret the degree of taphonomic alteration. The fossil-diagenetic processes inferred include substitution, fracturing, plastic deformation and different permineralization events. Combined analyses through X-ray diffractometry (XRD) and petrographic studies reveal the substitution of hydroxyapatite by francolite. The presence of fluorine -in one of the cases- suggests a link between the elemental composition and depositional environments: floodplain and fluvial channel. Permineralization stages include infilling of vascular canals, trabeculae and fractures with iron oxides and iron carbonate minerals during the burial history. This contribution represents an integral approach to the study of Cretaceous dinosaurs for assessing the diagenetic changes in the bone microstructure and the differential preservation of fossil remains in fluvial environments.

scholarly journals Diagenetic history of the upper Tanglewood Member (upper Ordovician) of the Lexington Limestone, central Kentucky, U.S.A. with special emphasis on petrographic differences between deformed and undeformed beds

2017 ◽  
Vol 53 ◽  
pp. 9-16
Author(s):  
Dibya Raj Koirala ◽  
Frank R. Ettensohn
Keyword(s):  
Upper Ordovician ◽  
Diagenetic Processes ◽  
Lexington Limestone ◽  
History Of ◽  
Sediment Deformation ◽  
Diagenetic History ◽  
Petrographic Study

Petrographic study was carried out for the upper Tanglewood Member (upper Ordovician) of the Lexington Limestone in order to understand its diagenetic history and predict whether the cementation is pre-deformational or post-deformational by comparing the deformed and undeformed beds of the same horizon. This study shows that the diagenetic processes, which have modified the sequence of the upper Tanglewood Member of the Lexington Limestone, consist of micritization, cementation, compaction, dolomitization and internal filling. Moreover, it indicates that the main episode of cementation took place after the sediment deformation.

scholarly journals Lithostratigraphy and microfacies analysis of Avanah Formation (Middle Eocene) in Gomaspan section northeast Erbil City, Kurdistan region, Iraq

2021 ◽  
Author(s):  
Irfan Sh. Asaad ◽  
Keyword(s):  
Middle Eocene ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
Petrographic Analysis ◽  
Microfacies Analysis ◽  
Dolomitic Limestone ◽  
Kurdistan Region ◽  
Thin Sections ◽  
Lithostratigraphic Units ◽  
Lagoon Environment

Lithostratigraphy and microfacies analysis of the Avanah Formation (Middle Eocene) were studied in the Gomaspan section in the Bina Bawi anticline, northeast of Erbil city, Kurdistan Region, Iraq. The field observations refer that the formation attains 56 m of medium to thick bedded yellow limestone, grey dolomitic limestone and blue marly dolomitic limestone interbedded with thin beds of blue marl and dark grey shale with an interval of sandy limestone in the middle part and thin to medium bedded limestone interbedded with red mudstone. The petrographic study of 29 thin sections of Avanah carbonates revealed that the majority of the matrix is carbonate mud (micrite) with few microspar. The skeletal grains include benthic foraminifera, dasycladacean green algae, ostracods, calcispheres, pelecypods, rare planktonic foraminifera and bryozoa in addition to bioclasts. Non-skeletal grains encompass peloids, oncoids, intraclasts and extraclasts with common monocrystalline quartz. Based on the field observation and petrographic analysis, three different lithostratigraphic units were identified. They are in ascending order: A-Thick bedded dolomitic marly limestone interbedded with shale. B- Bedded dolomitic limestone interbedded with shale and marl. C- Thin to medium bedded limestone interbedded with red mudstone. Depending on detailed microfacies analysis of carbonate rocks, three main microfacies and 12 submicrofacies are recognized. From the sum of all petrographic, facies, textural analyses, it is concluded that Avanah Formation in Gomaspan section, was deposited in shallow marine environment, semi restricted lagoon, in lower and upper parts and open lagoon environment in the middle part interval.

Salafism, Sectarianism, and National Identity in Iraqi Kurdistan

2021 ◽  
Vol 75 (3) ◽  
pp. 386-406
Author(s):  
Pishtiwan Jalal ◽  
Ariel I. Ahram
Keyword(s):  
Social Media ◽  
National Identity ◽  
Online Survey ◽  
Kurdistan Region ◽  
Political Ideologies ◽  
Iraqi Kurdistan ◽  
History Of

This article examines the history of Salafism within the Kurdistan Region of Iraq using interviews, archives, social media, and an online survey. Despite Salafism and nationalism generally being seen as rival political ideologies, Kurdish Salafis have over the last decade increasingly linked their sectarian struggle to the Kurdish ethno-nationalist cause. Such efforts provide new understandings both of Salafism and of Kurdish nationalism while also potentially destabilizing the alliance between Kurdish nationalist and Shi'i sectarian parties that has governed Iraq since 2003.

scholarly journals Reservoir Rock Properties of the Upper Cretaceous Shiranish Formation in Taq Taq Oilfield, Iraqi Kurdistan Region

2020 ◽  
Vol 22 (1) ◽  
pp. 363-388
Author(s):  
Dler H. Baban ◽  
◽  
Fuad M. Qadir ◽  
Aram R. Mohammed ◽  
◽  
...  
Keyword(s):  
Upper Cretaceous ◽  
Reservoir Rock ◽  
Rock Properties ◽  
Kurdistan Region ◽  
Iraqi Kurdistan

scholarly journals Stratigraphic And Microfacies Study Of Upper Campanian - Lower Maastrichtian Succession (Shiranish Formation) In Bade Village, Bekhere Anticline, Kurdistan Region, Northern Iraq

2021 ◽  
Vol 71 ◽  
pp. 47-55
Author(s):  
Zaid A. Malak ◽  
◽  
Omar A. Al-Badrani ◽  
Ezzat I. Al-Fandi
Keyword(s):  
Planktonic Foraminifera ◽  
Calcareous Nannofossils ◽  
Kurdistan Region ◽  
Planktic Foraminifera ◽  
Thin Sections ◽  
Northern Iraq ◽  
Lower Maastrichtian ◽  
Marly Limestone ◽  
Quartz Grains ◽  
Upper Campanian

The Upper Cretaceous Shiranish Formation outcropped close to Bade village and Bekhere anticline, Kurdistan region at northern Iraq and consists of alternating mixed tough grey limestone, marly limestone, marl beds interpreted as a middle - outer shelf – upper bathyal environments (basinal) depositional environment. Fifteen thin sections were studied under a polarized microscope to find out the petrographic component, fauna content, and for microfacies analysis. The major petrographic constituents are fossils, bioclastic grains, micrite matrix, and extraclast (quartz grains). Planktic foraminifera and nannofossils are the major particles within wackestone and packstone microfacies types. The planktonic foraminifera biozones from previous study (such as Globotruncana aegyptiaca, Gansserina gansseri, Racemiguembelina fructicosa, Plummerita hantkeninoides) and the recorded calcareous nannofossils biozones of Broinsonia parca, Reinhardtites levis, Arkhangelskiella cymbiformis, suggest a late Campanian to late Maastrichtian age.

scholarly journals Petrofacies investigations of the Cretaceous Pab Formation Rakhi Gorge Eastern Sulaiman Range Pakistan - Implication for reservoir potential

2021 ◽  
Vol 72 ◽  
pp. 37-46
Author(s):  
Mubashir Mehmood ◽  
◽  
Shahid Ghazi ◽  
Abbas Ali Naseem ◽  
Muhammad Yaseen ◽  
...  
Keyword(s):  
Total Porosity ◽  
Secondary Porosity ◽  
Thin Sections ◽  
Diagenetic Processes ◽  
Medium Reservoir ◽  
Primary Composition ◽  
Diagenetic Minerals ◽  
Reservoir Potential ◽  
Petrographic Study ◽  
Good Medium

Petrologic investigations of the sixty representative thin sections from the Pab Formation within Rakhi Gorge section Eastern Sulaiman Range Pakistan have been used to characterize different diagenetic patterns, identification of primary composition and reservoir characters. Sublithic, lithic and quartzose sandstones have been the principal constituents of the formation. The processes responsible for the late-stage alteration and diagenetic processes identified during the petrographic study include compaction of lithic fragments and mud clasts, formation of quartz overgrowth structures, feldspar replacement and alteration, cementation, and replacement of grains by clay minerals other ferrous elements and diagenetic minerals. The study shows that the initial porosity has been primary intergranular, but the secondary porosity has been originated in the rocks as a result of the alteration of the primary and secondary constituents, as well as fracturing. These facies characters replicate the reservoir quality including, good, medium, low-quality, and non-reservoir. Samples displaying average total porosity greater than 10 % have been declared as good quality. While rocks samples having 7 % or greater porosity are grouped as a medium reservoir. Those samples consisting of porosity values between 1 and 4% are considered as a low quality reservoir while those samples having porosity ranges low than 1% have been called non-reservoir. Based on the investigated parameters the studied samples from the Pab Formation displayed the characters of a medium reservoir that may hold significant hydrocarbon. This different quality including good and low quality zonation can be attributed to the facies and diagenetic change in the formation.

Minority Representation and Reserved Legislative Seats in Iraqi Kurdistan

2020 ◽  
Vol 7 (4) ◽  
pp. 381-402
Author(s):  
Farhad Hassan Abdullah ◽  
Hawre Hasan Hama
Keyword(s):  
Minority Groups ◽  
Regional Government ◽  
Kurdistan Region ◽  
Quota System ◽  
Religious Minority ◽  
Northern Iraq ◽  
Iraqi Kurdistan ◽  
History Of ◽  
Democratic Stability

Ethnic and religious minorities have played a significant role in the long history of Kurdistan. At an official level, their political position was significantly strengthened with the advent of autonomy for the Kurdistan Region in northern Iraq in 1992. Most importantly, a quota system was established that reserved seats for several minority groups in the Kurdistan Parliament, often cited as an example of tolerance for diversity and respect for minority rights. Nevertheless, there is a lack of empirical research examining how ethnic and religious quotas affect democratic stability, quality of representation, and opportunities to represent authentic interests within the Kurdistan Regional Government (KRG). The politicians who occupy the reserved seats have come under criticism for merely supporting the policy programs of the dominant Kurdish parties, which deprives ethnic and religious minority groups of authentic representation and exposes the minority parties to allegations that they are politically exploited. This article analyzes the dynamics of minority political participation in Iraqi Kurdistan, how representation has been affected by the dominance of the ruling parties, and factors that guide the behavior of minority politicians while serving in quota-allocated positions. It also examines the effects of reserving seats through the quota system on the political behavior of minority groups. To these ends, this article focuses on parliamentary quotas and their impact on democratic stability, decision-making, and the empowerment of minority groups in the Kurdistan Region.

Petrographic and isotopic evidence for diagenetic processes in Middle Jurassic sandstones and mudrocks from the Brae Area, North Sea

Clay Minerals ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 637-650 ◽  
Author(s):  
P. J. Greenwood ◽  
H. F. Shaw ◽  
A. E. Fallick
Keyword(s):  
Stable Isotope ◽  
Middle Jurassic ◽  
Pore Waters ◽  
Secondary Porosity ◽  
Diagenetic Processes ◽  
Sandstone Diagenesis ◽  
History Of ◽  
Area North ◽  
Diagenetic History ◽  
Stable Isotope Data

AbstractThe diagenetic history of an interbedded sequence of Middle Jurassic Sleipner (or Pentland), Hugin and Heather Formation sandstones and mudrocks from the Brae Area has been investigated using petrographic, stable isotope, fluid inclusion and K-Ar dating techniques. Generally, similar diagenetic processes affected both the mudrocks and sandstones resulting in the formation of carbonate, quartz and clay cements and evidence of dissolution and secondary porosity except for the absence of kaolinite in the Hugin Formation. The mudrocks were possible sources of some components involved in sandstone diagenesis but were not passive exporters of such reactants as similar reactions also occurred in the mudrocks. The stable isotope data indicate that most of the diagenetic processes occurred in the presence of marine or evolved marine pore-waters.

Application of backscattered electron microscopy in shale petrology

1983 ◽  
Vol 120 (2) ◽  
pp. 109-114 ◽  
Author(s):  
D. H. Krinsley ◽  
K. Pye ◽  
A. T. Kearsley
Keyword(s):  
Electron Microscopy ◽  
Upper Ordovician ◽  
Thin Sections ◽  
Backscattered Electrons ◽  
Particle Form ◽  
History Of ◽  
Backscattered Electron ◽  
Electron Microscopical ◽  
Diagenetic History ◽  
Z Contrast

SummaryA grey pyritic mudstone from Central Wales (Red Vein unit of the Dicellograptus anceps zone, Upper Ordovician Ashgill) has been examined in thin section by scanning electron microscopy using backscattered electrons. Using backscatter it is possible to identify individual mineral constituents of the mudstone by virtue of their atomic number (Z) contrast and differential hardness (relief). The amount of detail observable is far greater than that possible with optical microscopy. Valuable information can be obtained relating to particle form, orientation, texture and internal structure which aids in interpretation of the deformational and diagenetic history of the rock. The adoption of electron microscopical methods in the study of thin sections and polished rock chip surfaces promises to revolutionize the field of shale petrology.

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