The Sedimentology of the Late Campanian–Maastrichtian Sequence, Southwestern Iraq

Petrography, diagenesis, and facies analyses as well as the depositional environments of the late Campanian-Maastrichtian sequence in southwestern Iraq are studied in five keyholes. The sequence incorporates parts of the Hartha, Shiranish and Tayarat Formations. The Hartha Formation comprises creamy and organodetrital dolomite, grey dolomitic marl, and evaporites. The Shiranish Formation is composed of grey marl and claystone, whereas the Tayarat Formation is composed of grey ash, along with tough and fossiliferous dolomitic limestone inter-bedded with grey mudstone layers and/or wisps. Several diagenetic processes affected the sequence, such as neomorphic replacement, dissolution, dolomitization, and sulphate development. Some of these processes obliterated the primary textures. The late Campanian-Maastrichtian sequence consists of three microfacies (Dolomitic Intraclastic Limestone, Dolomitized Biomicrite, and Biomicrosparite Microfacies) and two lithofacies (Mudrock and Sulphates-Rock Lithofacies), in addition to Fine- to Medium-Crystalline Dolomite Lithotype. The Hartha Formation is evaporitic, possibly with supratidal sabkha deposits. The overlying Tayarat and Shiranish Formations reflect deposition in a warm tropical to subtropical reefal and open marine conditions, as deduced from faunal assemblages. Some effects of deep marine condition are evident by the presence of Shiranish facies. The sequence represents deposition in the central reef- fore reef area. The absence of isolated back-reef lagoon facies suggests that the reef was patchy without isolation of water in the middle shelf region. However, at the top of the sequence, i.e. at the end of the Cretaceous Period, restricted lagoons seem to have dominated the studied succession.

Ecosystem composition and environmental factors as drivers of pH on Barrier Reefs

<p>Tropical coral reefs are both biologically diverse and economically important ecosystems, yet are under threat globally, facing a multitude of stressors including global warming, ocean acidification, nutrient loading, over-fishing and sedimentation. Reef building corals precipitate an aragonite skeleton (CaCO<sub>3</sub>), which forms the base of the coral reef ecosystem, but it is this skeleton, which makes them sensitive to changes in ocean pH. To precipitate their skeletons, corals raise their internal pH, as seawater pH decreases this increases the energy demands needed to facilitate calcification. Furthermore, reductions in coral calcification has significant implications for reef health, potentially altering community structure with reef-wide consequences. Global ocean pH is decreasing due to rising atmospheric concentrations of CO<sub>2</sub>, however, dynamic ecosystems, alongside carbon and freshwater input from land, may result in coastal ocean pH being lower than is predicted by open ocean models. While it is predicted than ocean pH will decrease by 0.3 units by 2100 if emissions are not curbed, coral reefs, particularly those near major river outflow, may already be experiencing pH values similar to that of future scenarios.</p><p>Our aim was to determine the factors which influence pH in coastal reef systems and thus potentially mitigate or exacerbate atmospheric CO<sub>2</sub> mediated ocean acidification. This was achieved by contrasting reefs in distinct environmental settings and collecting data over a sufficient temporal resolution to permit the identification of pertinent drivers. To accomplish this we deployed fixed point observatories in the distinct reefs of Belize (fore and back reef sites), Fiji and Dominica. These custom-built platforms were equipped with a spectrophotometric pH sensor and a conductivity, temperature and dissolved oxygen (CT-DO) sensor from which data was logged at 30-120 minute intervals.</p><p>A strong diel cycle in pH, O<sub>2</sub> and temperature was observed at all reef sites in response to the changing balance of respiration and photosynthesis. However, the range of these changes varied between the different sites - Belize fore reef (pH 7.849­ – 8.000), Belize back reef (pH 7.897 – 8.039), Fiji (pH 7.951 – 8.0950) and Dominica (pH 7.843 – 8.144). Meteorological conditions, such as wind direction, affected the amplitude of diurnal pH variability and its relationship with other parameters, likely by influencing mixing and the spatial distribution of seawater and freshwater endmembers. The relationship between pH and O<sub>2</sub> varied between sites reflecting differences in ecosystem processes (e.g. calcification and primary production) and ecosystem composition (e.g. hard coral and algae cover, proximity to seagrass). Our data confirms that different reef sites are subject to varying degrees of ocean acidification and that controls on pH vary between environments. Furthermore, it highlights the need for widespread high-resolution monitoring to identify, and where possible enact protective measures, in vulnerable reef regions. As coral reefs continue to experience ocean acidification our data also serves to document baseline conditions against which future changes can be assessed.</p><p> </p>

FACIES DISTRIBUTION OF KAIS FORMATION IN “X” FIELD, SALAWATI BASIN, WEST PAPUA, INDONESIA

<p class="Abstract">Daerah penelitian lapangan “X” terletak di Formasi Kais, Cekungan Salawati, Papua Barat, Indonesia. Maksud dan tujuan dari penelitian ini adalah untuk menginterpretasikan fasies karbonat, beserta penyebarannya, baik secara vertikal maupun horizontal. Penelitian dimulai dengan penafsiran <em>litostratigrafi</em> menggunakan data <em>log</em> dan sayatan tipis, untuk membuat <em>type log</em>. Dilanjut dengan analisis sikuen stratigrafi dan <em>reef system</em> untuk menentukan penyebaran, dengan bantuan data seismik untuk dikorelasikan dengan sumur-sumur lainnya. Dari hasil analisis, terdapat 5 fasies pada daerah penelitian, yaitu: <em>Skeletal Debris Packstone-Wackestone, Coral Algal Grainstone – Boundstone, Skeletal Wackestone, Skeletal Packstone dan Coral Algal Packstone</em>. Terdapat pula 4 <em>reef system</em>, yaitu; <em>Back reef, reef crest, fore reef dan off reef</em>. Untuk mencapai tujuan akhir dari penelitian ini, maka dibuat peta penyebaran fasies.</p>

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

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

Lithological and isotopic (δ 13C and δ 18O) features of the Upper Silurian back-reef lagoon deposits of the Ilych River Basin, the Northern Urals

The Upper Silurian is widely developed in the Northern Urals, where it is represented by various facies. The continental slope facies and the reef shoal facies are well documented in the geological literature, while as back-reef lagoon facies have not yet been characterized in detail. The studied objects included two sections of the back-reef deposits in the Ilych River basin. In this work, we characterize rock types the make up the sections, and their isotopic characteristics. The Late Silurian back-reef lagoon was characterized by a mosaic sediments distribution, which included the island areas between which there were areas with a quiet hydrodynamic regime. In the latter, mainly muddy carbonates were accumulated, represented by clotted fenestral limestones. The area of small islands was characterized by a wide distribution of lime sands, which clastic material was derived from probable paleosoil carbonates. They are characterized by slightly increased δ 13C values, which, probably, reflects isotopic fractionation at the evaporative geochemical barrier. Dolomitization and karstification are described among secondary alterations in the studied sections. Cementstones is interpreted as karst cavities precipitates.

Diversity and Species Composition of Sponges (Porifera: Demospongiae) in Reef Flat of Barranglompo Island

Sponge is one of the biota that makes up coastal and marine ecosystems, especially in coral reef ecosystems and seagrass beds in both tropical and subtropical waters. The lack of research and knowledge about sponges (Porifera; Demospongiae), especially in the reef flat ecosystem on Barranglompo Island, is considered necessary to be studied and equipped for research on marine biological resources in the future. This research was conducted in March-November 2019 on Barranglompo Island. The purpose of this study was to determine the diversity and species composition and density of sponges (Porifera: Demospongiae) in the reef flat of Barranglompo Island, Sangkarang District, Makassar City. The method used in sponge data collection is a belt transect starting from ± 50m of shoreline drawn perpendicular to the end of the back reef at each station. The diversity of sponge species found was 22 species belonging to the Demospongiae class. The diversity of sponges on Barranglompo Island is still quite diverse, with a fairly even distribution.

Microbial-, fusulinid limestones with large gastropods and calcareous algae: an unusual facies from the Early Permian Khao Khad Formation of Central Thailand

The Early Permian (Kungurian) Khao Khad Formation of Central Thailand consists mostly of carbonates deposited on the western margin of the Indochina Terrane. This formation has yielded unusual microbial-fusulinid limestones with large gastropods which contribute most to the rock volume. With a height of more than 6 cm, the gastropods are amongst the largest Early Permian gastropods ever reported. Gastropods as major rock formers are rare in the Palaeozoic. This, and other recently reported invertebrate faunas from Thailand show that gastropods may dominate Permian fossil assemblages not only in diversity, but also regarding abundance and in some cases also regarding biomass. Besides gastropods, fusulinids, various calcareous algae, intraclasts and thick microbial-cyanobacterial (Girvanella and Archaeolithoporella) coatings and reticular microbial patches as well as thick inter- and intragranular radial fibrous cement crusts are present. The gastropods represent at least four species and belong probably to undescribed taxa. The fusulinid genus Pseudofusulina and Misellina (M.) termieri are reported from the Khao Khad Formation for the first time and indicate a Bolorian age. Calcareous algae are dominated by dasycladaceans followed by gymnocodiaceans and solenoporaceans. The studied limestone almost completely lacks metazoan reef builders such as corals and sponges. Likewise, brachiopods and bivalves are absent in the studied samples and echinoderms are very scarce. The carbonate is interpreted as product of shallow water, back-reef lagoonal platform community with a high productivity providing the large gastropods with sufficient food. However, conditions were too eutrophic for sessile filter feeders including metazoan reef builders.

Sedimentologi Batugamping Formasi Jayapura di Sepanjang Lintasan Dewarebru, Mamei-Waibron, Jayapura

The Pleistocene of the Jayapura Formation limestones well cropped out at Dewarebru Section, Mamey-Waybron, Jayapura Regency. Detailed descriptions of rock outcrops and petrography analysis of selected limestone samples is used to find out the limestone sedimentology characters. This Jayapura limestone was divided onto four limestone facies, including lithoclastic rudstone, bioclastic packstone, bioclastic grainstone and bioclastic wackesone rock facies. The rocks was deposited in a fore slope talus forming submarine alluvial fan, furthermore the rocks was deposited in a local slope on the back reef environment.Keywords: Limestone, petrography, stratigraphy, sedimentology, Jayapura

Sargassum epifaunal communities vary with canopy size, predator biomass and seascape setting within a fringing coral reef ecosystem

Tropical seascapes are comprised of a range of patch habitat types, yet we have only a partial understanding of how local patch condition and seascape position may influence patterns of marine biodiversity, particularly for invertebrate taxa. We investigated how the epifaunal abundance and biomass of tropical Sargassum varied with canopy size (volume, total length and dry weight), local patch conditions (macroalgal composition, canopy structure and invertivorous fish biomass) and seascape setting (nearshore, lagoon and back reef) within the Ningaloo fringing reef ecosystem, Australia. A total of 49431 epifauna, dominated by crustaceans and molluscs, were extracted from the thalli of 81 tropical Sargassum polycystum individuals. Epifaunal abundance and biomass were most strongly correlated with host Sargassum canopy volume and dry weight, respectively. Epifaunal abundance and biomass also varied significantly among separate Sargassum meadow patches, with a significant interaction between canopy size and seascape position. Considerable site-level variations in epifaunal biomass density (mg per g Sargassum dry weight) were best predicted by either seascape context or local invertivorous fish biomass. Sargassum within meadows furthest from the back reef tended to have the highest epifaunal biomass (dominated by molluscs), while meadows closest to the back reef were dominated by crustacea. Sargassum within meadows with a high local abundance of invertivorous labrids and serranids tended to have the lowest epifaunal biomass. Strong Sargassum canopy size-epifauna relationships indicate that even small differences in canopy extent have major flow-on effects for the trophic function of tropical marine ecosystems by affecting the epifaunal secondary productivity available to higher-order consumers, such as fishes.

Hubungan Antara Fasies Batugamping Terhadap Kualitasnya Sebagai Bahan Baku Semen Portland Menurut Kadar CaO dan Senyawa Terkait di Kuari B dan C, PT Indocement Tunggal Prakarsa Tbk Unit Palimanan, Cirebon

Batugamping merupakan sumberdaya alam kategori bahan galian industri nonlogam. Penelitian mengenai fasies dan kualitas batugamping di PT Indocement Tunggal Prakarsa Tbk Unit Palimanan dilakukan untuk mengetahui hubungan antara jenis fasies terhadap kualitas batugamping sebagai bahan baku semen portland. Penelitian dilakukan dengan pengamatan sampel batugamping secara makroskopis dan mikroskopis terhadap 20 singkapan batugamping Kuari B dan C. Setiap singkapan batugamping dilakukan pengambilan sampel hand speciment untuk analisis kualitas kimia menggunakan X-Ray Fluorescence dan analisis fasies lebih spesifik. Hasil analisis menyatakan bahwa batugamping Kuari B diklasifikasikan menjadi 3 fasies, yaitu packstone, bafflestone, dan rudstone yang terbentuk pada zonasi fasies reef core dan back-reef lagoon. Batugamping Kuari C diklasifikasikan menjadi 4 fasies, yaitu mudstone, wackestone, packstone, dan grainstone yang terbentuk pada zonasi fasies back-reef lagoon. Analisis kualitas kimia menunjukkan bahwa 8 sampel batugamping Kuari B berkualitas baik (kadar CaO>49%), sedangkan pada Kuari C didapati sebanyak 8 sampel berkualitas baik (kadar CaO >49%), 2 sampel berkualitas sedang (kadar CaO 40-49%) dan 2 sampel berkualitas rendah (kadar CaO<40%). Hasil penelitian menunjukkan bahwa jenis fasies batugamping yang bersifat grain supported seperti grainstone, packstone, bafflestone, dan rudstone cenderung menghasilkan batugamping dengan kualitas baik, sedangkan fasies batugamping yang bersifat matrix supported seperti mudstone dan wackestone akan menghasilkan batugamping dengan kualitas yang lebih buruk.