scholarly journals Microfacies Characterizations and Paleoenvironment of Upper Part of Qamchuqa Formation from Chwarqauran Section, Sulaimaniyia Area, Kurdistan Region, Iraq

2021 ◽  
Vol 54 (1B) ◽  
pp. 102-111
Author(s):  
Salah Hussain
Keyword(s):  
Benthic Foraminifera ◽  
Tidal Flat ◽  
Middle Part ◽  
Back Reef ◽  
Kurdistan Region ◽  
Reef Environment ◽  
Rock Samples ◽  
Facies Zone ◽  
Petrographic Study

The Qamchuqa Formation was studied in Chwarqauran section, Sulaimanyia, Kurdistan region, Northeastern Iraq. The lithology of the formation contains limestone throughout the whole section except for one bed of dolomite at the Middle part. Twenty-four slides were prepared from 24 rock samples that were taken from this section to discriminate the petrography and fossil content. The petrographic study shows four main microfacies including lime mudstone, wackestone, packstone, and floatstone. Additionally, there are four sub microfacies: bioclast wackestone, miliolid wackestone, bioclast packstone and orbitolinid packstone. However, the fossil content shows the abundance of benthic foraminifera against the planktonic. All the microfacies indicate facies zone 7, 8 and 9A which reflect deposition in the platform interior between the tidal flat to the mid ramp and back reef environment

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.

scholarly journals Influência dos fatores ambientais na preservação da microfauna de foraminíferos bentônicos no ambiente recifal dos Parrachos de Maracajaú, RN, Brasil

2007 ◽  
Vol 30 (2) ◽  
pp. 92-103
Author(s):  
Daniele Silva Batista ◽  
Claudia Gutterres Vilela ◽  
Eduardo A. M Koutsoukos
Keyword(s):  
Coral Reef ◽  
Benthic Foraminifera ◽  
Statistical Data ◽  
Rio Grande ◽  
Taxonomic Composition ◽  
Post Mortem ◽  
Reef Environment ◽  
Coral Reef Environment ◽  
Foraminíferos Bentónicos ◽  
Taphonomic Processes

Taphonomy focuses on the post-mortem processes of transport and preservation of biotic remains in the sedimentary record, and as such it has important applications for paleoenvironmental reconstructions. The aim of this work is to verify the degree of dissolution, abrasion, bioerosion and fragmentation in foraminiferal tests recovered from bottom sediments of the Parrachos de Maracajaú, Rio Grande do Norte, and to estimate the influence of these taphonomic processes in the distributon and preservation of the assemblages. Fifty-one species of benthic foraminifera have been found in the studied site. The taxonomic composition is typical of a coral reef environment. Amphistegina lessoni, Sorites marginalis, Quinqueloculina lamarckiana, Q. agglutinans, Peneroplis carinatus and Archaias angulatus are abundant in all the studied localities. The energy of the environment was interpreted as high. The species have been grouped into two groups, and the statistical data show that all four taphonomic processes (dissolution, abrasion, bioerosion and fragmentation) have influenced the distribution and preservation patterns of the foraminifera.

Cretaceous (Aptian-Maastrichtian) stratigraphy of the Shiranish Islam area, northern Iraq

Stratigraphy ◽  
2021 ◽  
pp. 29-70
Author(s):  
Stephen R. Packer ◽  
Kathryn L. Canner ◽  
Ali Chalabi
Keyword(s):  
Analytical Data ◽  
Middle Part ◽  
Kurdistan Region ◽  
Clastic Material ◽  
Larger Benthic Foraminifera ◽  
Shallow Marine ◽  
Northern Iraq ◽  
Faunal Succession ◽  
World Class ◽  
Early Late

ABSTRACT: The Kurdistan region of northern Iraq contains world-class outcrops that make it possible to examine the Cretaceous deep and shallow marine Tethyan faunal succession. Six separate sections covering the Shiranish, Bekhme, Mergi and Qamchuqa formations have been investigated in this study from the Shiranish Islam area. A number of papers have been published on this area, but no comprehensive biostratigraphic record has been published that fully documents the Cretaceous stratigraphy and the chronostratigraphic interpretation of the succession. As a result, this has led to significant lithostratigraphic and chronostratigraphic uncertainties. The upper part of the Qamchuqa is pervasively dolomitized. Rare occurrences of foraminifera are found in less dolomitized intervals in thin-section indicating an early - middle Albian age for the top of the formation. A thin interval comprising the Gir Bir Formation is Cenomanian in age and is present between the top of the Qamchuqa Formation and the overlying conglomerate. Historical studies indicate that the Turonian Mergi Formation occurs between the Qamchuqa and Bekhme formations, but our field and analytical data does not support it as a discrete lithostratigraphic entity, as Turonian aged faunas were not recognized. The conglomerate separating the top of the Gir Bir and base of the Bekhme is subdivided into three units (A, B & C). Units A and B are late Cenomanian to early Turonian age, whilst Unit C is of Campanian age. A significant hiatus separates the Gir Bir and the Bekhme, which encompasses the intra Turonian to Santonian. The limestone facies of the lower part of the Bekhme Formation contains rich benthic foraminiferal faunas (miliolids, Pseudedomia, Cuneolina) of early - early middle Campanian age. This lower - lower middle Campanian section at Shiranish Islam is considered to be equivalent of the upper part of the Sa'di Formation in central Iraq and is therefore re-assigned on the basis of chronostratigraphic attribution to the Sa'di (equivalent) herein. The top of the early - early middle Campanian biofacies is abruptly truncated by an omission surface, marked by an erosive base, an influx of clastic material and a major up-section biofacies change characterized by an influx of Pseudosiderolites and Orbitoides representing an intra-Campanian hiatus. The bioevent sequence suggests that this hiatus at Shiranish Islam comprises at least the middle Campanian (upper part of the G. elevata Zone) into the late Campanian (intra R. calcarata Zone), from approximately 80.64 Ma to 76.09 Ma with 4.55 my missing. The middle part of the Bekhme Formation comprising the Pseudosiderolites - Orbitoides facies is thin (c. three meters) and is re-assigned to the Lower Bekhme Member. The boundary between the Lower Bekhme Member and the Upper Bekhme Member is conformable and marked by a gradual up-section reduction in the size and presence of larger benthic foraminifera (Orbitoides, Pseudosiderolites) and an increase in the planktic component (small planktics and calcispheres). This trend of gradually increasing water depth continues into the Shiranish Formation, with no apparent major breaks in deposition. The Campanian - Maastrichtian boundary falls within Unit A of the Shiranish Formation. Deposition of the Shiranish continued into the earliest late Maastrichtian and is unconformably overlain by the Danian Kolosh Formation. The hiatus between the top of the Cretaceous and the Paleocene extends from the early late Maastrichtian (c. 68.86 Ma) to the upper part of the Danian (62.2 Ma) with an estimated duration of 6.66 my.

An Analysis of Competitive Interactions in a Patch Back-Reef Environment

Ecology ◽  
1981 ◽  
Vol 62 (4) ◽  
pp. 1107-1120 ◽  
Author(s):  
Ann Houston Williams
Keyword(s):  
Competitive Interactions ◽  
Back Reef ◽  
Reef Environment

scholarly journals VNITŘNÍ ZONÁLNOST TĚLES HORNIN TĚŠÍNITOVÉ ASOCIACE VE SLEZSKÉ JEDNOTCE: KORELACE PETROGRAFICKÝCH A PETROFYZIKÁLNÍCH PARAMETRŮ

2014 ◽  
Vol 21 (1-2) ◽  
Author(s):  
Kristýna Schuchová ◽  
Zdeněk Dolníček
Keyword(s):  
Magnetic Susceptibility ◽  
Igneous Rocks ◽  
Western Carpathians ◽  
Published Data ◽  
Modal Composition ◽  
Petrophysical Parameters ◽  
Rock Samples ◽  
Outer Western Carpathians ◽  
Petrographic Study

This article is focused on petrography of igneous rocks of the teschenite association and its correlation with selected petrophysical parameters. These igneous rocks were studied at three localities in the Silesian unit (Outer Western Carpathians) – Hodslavice, Žilina near Nový Jičín and Tichá. We conducted petrographic study (including modal composition based on planimetry) and then we compared results with previously published data on magnetic susceptibility and density of the same rock samples. The primary magmatic phases (clinopyroxenes, amphibole, biotite, opaque phases, feldspars and analcime) show in all cases less or more signs of post-magmatic alteration, giving rise mainly to secondary chlorite, carbonate and “limonite”. The amount of chlorite ranges from 21 to 23, 3 to 9, and 16 to 35 mod. % and those of carbonate vary from 5 to 15, 3 to 4, and 16 to 24 mod. % in Hodslavice, Žilina near Nový Jičín, and Tichá, respectively. The values of magnetic susceptibility range from 5.56 × 10-8 to 7.66 × 10-5, 5.07 × 10-7 to 1.61 × 10-5, and 2.46 × 10-7 to 2.93 × 10-5 SI and those of density are between 2.50 and 2.77, 2.66 to 3.88, and 2.65 to 2.86 g/cm3 in Hodslavice, Žilina near Nový Jičín, and Tichá, respectively. Correlation of petrographic and petrophysical parameters suggests that various postmagmatic alterations (including chloritization, carbonatization and weathering associated with formation of limonite) can influence the values of magnetic susceptibility and density. The intensity of these alterations varies significantly among samples and sites.

scholarly journals Lithostratigraphy and Sedimentological Characteristics of the Calciturbidites of the Babadağ Formation-Tavas Nappe (SW Turkey)

2021 ◽  
Vol 74 (1) ◽  
pp. 1-20
Author(s):  
Basiru Mohammed Kore ◽  
◽  
Murat Gül ◽  
Ceren Küçükuysal ◽  
Bilal Sarı ◽  
...  
Keyword(s):  
Depositional Environment ◽  
Sedimentary Rocks ◽  
Middle Part ◽  
Sea Level Fluctuations ◽  
Sw Turkey ◽  
Input Control ◽  
Lithostratigraphic Units ◽  
Ca Substitution ◽  
Sediment Input ◽  
Facies Zone

The Lycian Nappes contain slices of ophiolites and sedimentary rocks of various ages that crop out in SW Turkey. They evolved and were emplaced under the effect of the Late Cretaceous-Miocene compressional regime. The Tavas Nappe is part of the Lycian Nappes and contains Jurassic-Eocene sediments. The Babadağ Formation, forming the middle part of the Tavas Nappe, is composed of limestone at the base and various sized calciturbidites with chert intercalations in the upper part. The Standard Microfacies Classification (SMF of FLÜGEL, 2004) indicates that the entire unit was deposited mainly in a deep-shelf environment (Facies Zone – FZ-2), deep-sea (FZ-1), toe of slope (FZ-3) and on the continental slope (FZ-4). Calcite and quartz dominate the bulk mineralogy of the calciturbidites with higher SiO2 and CaO weight percentages than other major oxides. Additionally, the presence of Na2O, K2O, Al2O3, MgO, TiO2 and Fe2O3 is associated with the local sediment input. Tectonism and sea level fluctuations were the main triggering factors of the changes in the original depositional environment of the Babadağ Formation. Additionally, grain size and the amount of sediment input control the calciturbidite type and extension. Si enriched water circulation and Si and Ca substitution were responsible for the abundant chert formation during diagenesis of the units. Post depositional tectonic activities during transportation and emplacement of the nappes resulted in calcite filled cracks that cut both the calciturbidites and cherts. Study of the different nappe slices provides valuable information about syn- and post- depositional changes of the lithostratigraphic units.

scholarly journals Oligocene-Early Miocene Planktonic Microbiostratigraphy and Paleoenvironments of the South Slovakian Basin (Lučenec Depression)

2015 ◽  
Vol 65 (5) ◽  
pp. 451-470 ◽  
Author(s):  
Silvia Ozdínová ◽  
Ján Soták
Keyword(s):  
Benthic Foraminifera ◽  
Middle Part ◽  
Calcareous Nannofossils ◽  
Zone Boundary ◽  
Benthic Species ◽  
Planktonic Foraminifers ◽  
Benthic Foraminifers ◽  
High Productivity ◽  
Eutrophic Water ◽  
Quantitative Analyses

Abstract Oligocene and Lower Miocene sediments of the Lučenec Depression were studied to demonstrate the planktonic bioevents and climatic proxies from the Číž Formation (Rupelian) and Lučenec Formation (Chattian-Aquitanian) on the basis of quantitative analyses of foraminifers and calcareous nannofossils. The oldest nannofossil assemblages of the Číž Formation belonged to the NP23 Zone and were dominated by Reticulofenestra ornata known for preference of temperate eutrophic water conditions. An increase in bioproductivity was documented by abundant large-sized planktonic foraminifers (e.g. Turborotalia ampliapertura, Paragloborotalia nana, Subbotina gortanii) and epifaunal to shal-low-infaunal benthic species. The middle part of the Číž Formation reveals a lowstand progradation of deltaic sediments of the Rapovce Member. There, the planktonic foraminifers are impoverished in both size and diversity, containing mostly tenuitellid and cassigerinellid species, probably as a result of decreased salinity and increased anoxia in the Tard Clay. Contrary of this, the benthic foraminifers are rich, mainly the infaunal forms of uvigerinid species. They probably proliferated due to a high organic flux from riverine input. Open marine conditions were restored in the upper part of the Číž Formation above the lowest occurrence (LO) of Cyclicargolithus abisectus on the NP23-NP24 zone boundary. The transitional interval between the Číž and Lučenec formations (O5/O6 - NP24/25) was approximated by the HOs of Paragloborotalia opima and Sphenolithus distentus and the LOs of Globigerinoides primordius and Pontosphaera enormis. Benthic foraminifera of the Lučenec Formation indicate a high productivity and oxygen-deplected environ-ments. The Oligocene-Miocene boundary in the Lučenec Formation was appointed by the HOs of Helicospahera recta and Dictyococcites bisectus. Foraminiferal markers of this boundary were established from the HO of Globigerina ciperoensis and the LO of G. ottnangiensis. The highest nannofossil dating in the Lučenec Formation is recorded by the LOs of Helicosphaera mediterranea (NN1 Zone) and Discoaster druggi (NN2 Zone). The uppermost part of the Lučenec Formation contained many Paratethys benthic foraminifera, such as Uvigerina posthantkeni.

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 BENTHIC FORAMINIFERA IN SOUTH WAIGEO WATERS, RAJA AMPAT, WEST PAPUA

2016 ◽  
Vol 27 (1) ◽  
pp. 1 ◽  
Author(s):  
Suhartini M. Natsir ◽  
M. Subkhan
Keyword(s):  
Coral Reef ◽  
Benthic Foraminifera ◽  
Petroleum Industry ◽  
Reef Growth ◽  
Reef Environment ◽  
West Papua ◽  
Reef Environments ◽  
Coral Reef Environment ◽  
Stress Environment ◽  
Papua Barat

Waigeo Island is one of four large islands of the Raja Ampat group, West Papua Province. This area lies in the heart of the coral triangle region as the most marine bio-diversity on Earth. Coral reef ecosystem of the Waigeo is a favorable habitat for various organisms including foraminifera. Foraminifera have been proven as useful indicator of water quality surrounding the coral reef environment since FORAM Index was formulated. It gives additional importance of foraminifera beside their common uses on micropalaeontology for petroleum industry and palaeoecology. Therefore, it is very important to obtain data of the benthic foraminifera from various coral reef environments in Indonesia, such as around Waigeo Island. Sediment samples of this study were collected from 12 sites in southern part off Waigeo Island, on July 2011. Observation on benthic foraminifera shows that the study area is dominated by symbiotic bearing benthic foraminifera, Amphistegina lessonii, belongs to Suborder Rotaliina. This occurrence increases the values of FORAM Index (FI) at certain sites. Generally, the values of FI from most sites are high (FI>4) that provide a good indication for reef growth or recovery. The values of FI less than 2 are found at RJ3 and RJ4 indicate stress environment for reef growth and they are dominated by opportunistic and heterotrophic functional groups of Elphidium and Quinqueloculina. Keywords: benthic foraminifera, high value FI, Waigeo Island, West Papua Pulau Waegio merupakan salah satu dari empat pulau besar di Kepulauan Raja Ampat, Provinsi Papua Barat. Wilayah in terletak di jantung segitiga terumbu karang sebagai pusat paling kaya keanekaragaman hayatinya di bumi. Ekosistem terumbu karang Waigeo merupakan habitat yang cocok bagi kehidupan berbagai organisme termasuk foraminifera. Foraminifera telah terbukti sebagai indikator kualitas air sekitar terumbu karang setelah diformulasikan Indeks FORAM. Dengan demikian foraminifera telah mempunyai kegunaan tambahan selain fungsi umum dalam bidang mikropaleontologi pada industri perminyakan dan paleoekologi. Oleh karena itu sangat penting untuk mendapatkan data foraminifera bentik dari ekosistem terumbu karang di wilayah Indonesia, seperti perairan Pulau Waigeo. Sampel sedimen untuk studi ini diambil di 12 titik lokasi sebelah selatan Pulau Waigeo pada bulan Juli 2011. Hasil pengamatan memperlihatkan bahwa daerah penelitian di dominasi foraminifera bentik yang bersimbose dengan terumbu karang, Amphistegina lessonii, anggota Subordo Rotaliina. Kehadirannya meningkatkan nilai FI dari titik lokasi tertentu. Sebagian besar titik lokasi mempunyai nilai FI>4 memberi indikasi bahwa kondisi perairannya kondusif untuk pertumbuhan karang yang terletak di ekosistem terumbu karang. Secara umum, nilai FI di sebagian besar titik lokasi tinggi (>4) yang member indikasi kondisi lingkungan bagus bagi pertumbuhan karang. Nilai FI rendah (

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