Development of Virtual Simulation Experimental Software of Marine Platform Structure

Due to the harsh offshore exploitation environment, students are unable to conduct field investigation in offshore platforms. In this scenario, virtual simulation is an effective way to solve this problem. This paper introduces in detail a Virtual Simulation Experimental Software of Marine Platform Structure, which is closely integrated with the course content and engineering reality. Through the operation and learning of platform site selection, platform structure assembly, platform structure display, can realize the students' knowledge of platform structure composition mastery, and at the same time improve the students' participation and motivation. In addition, the system can automatically generate the experiment report and give the operation score reference to realize the teacher's quality control of the experiment course.

Sedimentology, stratigraphy and clinoform architectures of a siliciclastic shallow-marine platform: insights from the Late Ordovician of the Anti-Atlas (Morocco)

<p><span><span>The Moroccan Anti-Atlas consists of a several kilometers thick sediment pile accumulated on the northern Gondwana platform since the latest Precambrian (Ediacaran). This study focuses on the Ktaoua Group, early Late Ordovician (Mid-Sandbian to Katian) in age, which records a major and multiphase transgressive/regressive cycle above the shallow marine sandstones of the underlying First Bani Group. In the western Central Anti-Atlas, the Ktaoua Group is formed by offshore shales to coastal sandstones organized in regressive parasequences. Here, high-resolution field-based stratigraphy is used to constrain the shelf architecture and clinoforms geometries within the Ktaoua Group.</span></span></p><p><span><span>Whereas the lower part of the Ktaoua Group records parasequences from silty-shale to fine to coarse sandstones with hummocky-cross-stratification (HCS), its upper part oscillates between HCS beds and very coarse sandstones. Ferruginous, condensed horizons usually drape the parasequences. In this study, we investigate the platform geometry through the correlation of the stacking patterns of seventeen stratigraphic logs along an 85 km long, well-exposed cliff. Drone images support the logging and the correlations of the sections by imaging clinoforms geometries. </span></span></p><p><span><span>Several decameters of fine to coarse sandstones can be observed to grade laterally into condensed level(s) within a few kilometers, hence evidencing clinoforms pinching out. The visible orientation of the clinoforms along the cliff exposures show a proximal to distal trend from the south-west to the north-east, in agreement with the overall basin geometry. Three clinoforms with distinct geometries and lateral evolution of facies associations are highlighted. The distal part of a clinoform, 15 m in thickness, pinches out onto the top of the underlying First Bani Group within 7 km. The overlying regressive parasequence, approximatively 50 m thick, remains consistent more than 50 km, and is understood as a prograding clinoform. A third clinoform, capped by a prominent sandstone body constantly thicker than 20 m over ca. 20 km, disappears within its last 3.5 km onto the underlying clinoform. This study offers new details on the progradation and regression geometries along a giant platform within a detailed stratigraphic framework.</span></span></p><p><span><em><span>We would like to thank the Pacha and the Gendarmerie Royale of Foum-Zguid, the governor of Tata and the different persons who gave their approval and facilitated the use of the drone in the region of Souss-Massa for their precious help.</span></em></span></p>

Decoupling of morphological disparity and taxonomic diversity during the end-Permian mass extinction

An increasing number of unexpectedly diverse benthic communities are being reported from microbially precipitated carbonate facies in shallow-marine platform settings after the end-Permian mass extinction. Ostracoda, which was one of the most diverse and abundant metazoan groups during this interval, recorded its greatest diversity and abundance associated with these facies. Previous studies, however, focused mainly on taxonomic diversity and, therefore, left room for discussion of paleoecological significance. Here, we apply a morphometric method (semilandmarks) to investigate morphological variance through time to better understand the ecological consequences of the end-Permian mass extinction and to examine the hypothesis that microbial mats played a key role in ostracod survival. Our results show that taxonomic diversity and morphological disparity were decoupled during the end-Permian extinction and that morphological disparity declined rapidly at the onset of the end-Permian extinction, even though the high diversity of ostracods initially survived in some places. The decoupled changes in taxonomic diversity and morphological disparity suggest that the latter is a more robust proxy for understanding the ecological impact of the extinction event, and the low morphological disparity of ostracod faunas is a consequence of sustained environmental stress or a delayed post-Permian radiation. Furthermore, the similar morphological disparity of ostracods between microbialite and non-microbialite facies indicates that microbial mats most likely represent a taphonomic window rather than a biological refuge during the end-Permian extinction interval.

Taphonomy and palaeopathology of two mysticete whales, upper Miocene Pisco Formation, Peru

Two mysticete fossil whales from the upper Miocene of the Pisco Formation in Peru are described that show healed bone-fractures in ribs. One specimen is preserved in a tuffaceous diatomaceous siltstone and the other specimen is preserved in siltstone. Both specimens are well preserved, mostly articulated and almost complete. Shark teeth were found associated with one of the skeletons, but both specimens lack any trace evidence for the activity macro-scavengers. We suggest that the cause of bone fracture may have been collision with rocky shores, other wales, or large predators. The fact that the rib fractures healed indicates that the whales did not die due the bone fractures. Sedimentologic and paleontological evidence indicate that they were rapidly buried in the marine platform with well-oxygenated water

Exploratory Data Analysis: Connecting X-Ray Diffraction and Lithogeochemical Data

The Vazante Group is a district in east-central Brazil that consists of a carbonate-dominated marine platform sequence of Late Mesoproterozoic age. The district is home to a north-south belt that contains several zinc mines, but the petrogenesis of the ore body is not yet fully understood. Samples from this district were analyzed using both X-Ray Diffraction (XRD) and lithogeochemical assay techniques by Dr. Neil Fernandes in 2016. An analysis was conducted in order to explore the statistical correlations between the XRD and lithogeochemical test results. The purpose of the analysis was to determine whether the raw (uninterpreted) XRD data alone could be used to identify the samples enriched in zinc and other elements indicative of economic mineralization. The results showed very subtle trends that were not significant enough to make conclusions about the possibility of using XRD data without accompanying lithogeochemical data. The higher-than-average correlation of the intensity of pyrite peaks in the XRD data with elements associated with mineralization suggests that there are potentially more robust and significant trends that were not fully uncovered by this analysis, as pyrite has already been associated with mineralized zones. The analysis process itself could be valuable in future projects, and future work on this technique is proposed that uses machine learning to cluster the data and detect trends that may not be obvious using conventional techniques.

Geochemical significance and Formation of Suçatı Pb-Zn Deposits – Eastern Taurides

<p><strong>Geochemical significance and Formation of  Suçatı Pb-Zn Deposits – Eastern Taurides</strong></p><p>Hatice Nur Bayram<sup>(1)*</sup>, Ali Erdem Bakkalbaşı <sup>(1)*</sup>, Mustafa Kumral<sup>(1)</sup>, Ali Tuğcan Ünlüer<sup>(1)</sup></p><p><sup>(1)</sup>Istanbul Technical University, Department of Geological Engineering, Istanbul/Turkey</p><p>(*E-mail: [email protected])</p><p> </p><p>The Middle Tauride Orogenic Belt is a productive enviroment in terms of Pb-Zn ore deposits, mostly associated with Permian aged dolomitized, shallow marine platform type carbonate rocks. There have been many studies on the origin of the ore deposits in the region, there are two important approaches that stand out for the formation of the ore deposits: the first theory is hydrothermal deposits with magmatic origin, and the other theory is Missisippi Valley-type (MVT) deposits related with the carbonate rocks commonly found in the region. Field studies at the Suçatı (Kayseri – Yahyalı, Central Anatolia, Turkey, East of Aladağlar extension of the Taurides) ore district in the Aladağ geologic unit indicate that the deposits in the region are associated with Paleo-Tethys limestones, fossiliferous limestones and dolomitic limestones. Mineralization is related to Lower Permian aged carbonate rocks include primary mineralization ore minerals as galena, sphalerite, smithsonite and goethite and as a product of hydrothermal activity, calcite mineral filled within fractures and cracks represents gangue minerals. As a result of geochemical analysis of the samples collected from the ore zones, PbO values range between 25.93% - 0.012%, ZnO values range between 51.01% - 0.042%, Fe<sub>2</sub>O<sub>3</sub> values range between 42.81% - 10.21%. In conclusion hydrothermal activities closely related with compressional and extentional tectonic regimes took place in multiphase mineralization.</p><p> </p><p><strong>Keywords:</strong> Pb-Zn Deposits, MVT, Taurides, Yahyalı</p>

FINITE-ELEMENT ANALYSIS OF STRESSES OF THE SUPPORT OF THE MARINE PLATFORM

The paper considers the drilling support of an oil-based offshore platform such as the «Berkut» platform. The support is subjected to various loads: underwater currents, bulk ice, wind load. The problem of determining stresses is solved. A finite element analysis of the arising stresses is performed.

Microfacies and Palaeoenvironment of Avanah Formation (Middle Eocene) Geli Bessri in Dohuk City / North of Iraq

This research is based on (23) Samples selected from the Avanah Formation (Middle Eocene) in the Geli Bessri section in Dohuk to recognize the microfacies and depositional environments. The Avanah Formation consists of rocks of marly limestone and limestone containing Alveolina and thin layers of sandstone lithofacies found in the lower part of the Formation. The depositional environment was determined depending on skeletal and non- skeletal grains. The facies of the Avanah Formation were divided into four main microfacies and four submicrofacies based on skeletal and non- skeletal grains: The mudstone and wackestone, which is divided into benthic foraminifera wackestone and Rotaliids wackestone, the Formation also contains the packstone which is divided into the Rotaliid - Miliolid Lime packstone submicrofacies and benthic foraminifera lim packstone submicrofacies, in addition to the lime grainstone and also contains the Sandstone lithofacies located at the bottom of the Formation. The Avanah Formation in the middle and upper part is subjected to diagenesis process early dolomization and it is observed this through floating dolomite rohmb. According to the results of the facies analysis and the presence of foraminifera fossils, the Formation was deposited in open marine platform to restricted platform interior. http://dx.doi.org/10.25130/tjps.25.2020.014