Crystallisation of magmatic topaz and implications for Nb-Ta-W mineralisation in F-rich silicic melts - The Ary-Bulak ongonite massif

Textural, mineralogical and geochemical data on F-rich rhyolite (ongonite) from the Ary-Bulak massif of eastern Transbaikalia help constrain the formation of magmatic topaz. In these rocks, topaz occurs as phenocrysts, thus providing compelling evidence for crystallisation at the orthomagmatic stage. Cathodoluminescence images of topaz and quartz reveal growth textures with multiple truncation events in single grains, indicative of a dynamic system that shifted from saturated to undersaturated conditions with respect to topaz and quartz. Electron microprobe and Raman analyses of topaz indicate near-pure F composition [Al2SiO4F2], with very limited OH replacement. Laser ablation ICP-MS traverses revealed the presence of a large number of trace elements present at sub-ppm to hundreds of ppm levels. The chemical zoning of topaz records trace element fluctuations in the coexisting melt. Concentrations of some trace elements (Li, Ga, Nb, Ta and W) are correlated with cathodoluminescence intensity, thus suggesting that some of these elements act as CL activators in topaz.The study of melt inclusions indicates that melts with different F contents were trapped at different stages during formation of quartz and topaz phenocrysts, respectively. Electron microprobe analyses of glass in subhedral quartz-hosted melt inclusions indicate F ≤ 1.2 wt.%, whereas irregular-shaped melt inclusions hosted in both topaz and quartz have F ≤ 9 wt.%. Cryolithionite [Na3Li3Al2F12] coexists with glass in irregular inclusions, implying high Li contents in the melt. The very high F contents would have increased the solubility of Nb, Ta and W in the melt, thus allowing progressive concentration of these elements during magma evolution. Crystallisation of Nb–Ta–W-oxides (W-ixiolite and tantalite–columbite) may have been triggered by separation of cryolithionite, which would have caused F and Li depletion and consequent drop in the solubility of these elements

Laparoscopic Roux-en-Y reconstruction in a patient with afferent loop syndrome and peptic ulcers of gastroenteroanastomosis - A first experience

This paper is devoted to the description of a currently rare clinical observation of the surgical treatment of a patient with postgastroresection syndrome (afferent loop syndrome and peptic ulcers of gastroenteroanastomosis) - resection of the stomach stump with laparoscopic Roux-en-Y reconstructio

Olivine-lamproite from Ybytyruzú Lamproite Field, Eastern Paraguay

En el presente trabajo se realiza la descripción de la geología, la química mineral, comentarios sobre su geoquímica y caracterización de la intrusión Yzu-4 emplazada en el Campo de rocas lamproíticas del Ybytyruzú, Paraguay Oriental. De acuerdo a la petrografía y química mineral, con refuerzos de química de roca (elementos mayores, menores, trazas e isotopos de Sr y Nd), Yzu-4 se trata de una sanidina diopsido analcima, olivino lamproita expuesta junto a un inferido (a partir de imágenes de satélite Landsat 4-5 y 7) conducto alimentador (feeder) de una intrusión en forma de pipe de unos 900x900 metros de diámetro y que está situada a menos de 1500 metros de un otro conducto de olivino lamproíta rica en micas (también inferido como pipe diamantífera). El Campo de lamproítas del Ybytyruzú yace sobre el corazón Archon profundo del cratón Rio de la Plata.In the present work is carried out the description of geology, mineral chemistry,geochemistry, and characterization of the Yzu-4 intrusion that occurs in the Ybytyruzú lamproites field,Eastern Paraguay. According to the petrography and mineral chemistry, with reinforcements of rockchemistry (major, minor and traces elements and isotopes of Sr and Nd), Yzu-4 belongs to sanidinediopside analcime, olivine lamproite exposed next to a inferred (from Landsat 4-5 and 7 satellite imagery)pipe-shaped intrusion of 900x900 meters in diameter and located less than 1500 meters from anotherintrusion of diamond- bearing olivine lamproite rich in micas (also inferred as pipe). The Ybytyruzúlamproites field lies on the deep Archon heart of Rio de la Plata craton.Fil: Baez Presser, Jaime Leonardo. Jaime Presser Exploraciones; ParaguayFil: Vladykin, Nikolay V.. Institute Of Geochemistry; RusiaFil: Bitschene, Peter Rene. Museo Ciencias Naturales de Gerolstein; AlemaniaFil: Tondo, Matías J.. Universidad Nacional de Asunción; ParaguayFil: Acevedo, Rogelio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Alonso, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta; ArgentinaFil: Benitez, Pedro. Universidad Nacional de Asunción; Paragua

Legal aspects of gender identity in Ukraine

The issue of gender identity in the modern world is becoming increasingly relevant. The place of a person's right to recognise their gender identity in the Ukrainian legal plane is uncertain. The study considers the specific features of regulating the human right to recognise gender identity and gender reassignment in Ukraine. The authors of the study consider personal non-property rights of an individual as a specific concept, and somatic rights – as a generic concept, the main meaning of which is the ability to dispose of one's body. Accordingly, a person's right to recognition of their gender identity is a personal non-property right. In Ukraine, legal regulation of gender change is carried out, but certain regulations come into force only in the event of a legal fact of gender change, although their provisions regulate the direct implementation of such a right. However, gender identity is the third most common cause of discrimination. It is necessary for Ukrainian legislation to update the regulatory framework that governs the procedure for changing gender. It is worth paying attention to the correct use of terminology in these relations

A STUDY OF INFLUENCE OF THE HEAT TRANSFER FLUID VOLUME ON LOOP THERMOSYPHON EFFICIENCY

The influence of the heat transfer fluid volume on loop thermosyphon efficiency has been studied using infrared camera. The study has been carried out by considering of different spatial positions

Возможности ультразвукового исследования в выявлении дивертикулита в условиях стационарного отделения скорой помощи

The aim of this prospective study was to evaluate ultrasound capabilities in differential diagnosis of intestinal diverticular disease, diverticulitis and other acute abdomen pathology.Material and methods. The study included 29 patients at the age of 48-95 years, which were admitted to emergency department with clinical symptoms of acute abdomen pain. All patients underwent complex clinical examination, comprising laboratory and instrumental diagnostic methods. Ultrasound of intestines was performed according to a specially developed step-by-step algorithm.Results. Sensitivity of the method was 68%, specificity 80%, accuracy 72.0%, PPT 86.0%, NPT 57.0%.Conclusion. Rather high diagnostic informative value and non-invasiveness of intestine's ultrasound allow to reconsider the sequence of instrumental methods of diagnosis for patients with suspicion on acute diverticulitis, and to consider ultrasound as a first line method of diagnosis.Цель исследования: оценка возможностей ультразвукового исследования в дифференциальной диагностике дивертикулярной болезни кишечника, диверти-кулитов и другой острой абдоминальной патологии.Материал и методы. В исследование включено 29 пациентов в возрасте от 48 до 95 лет, экстренно поступивших в стационар с клинической симптоматикой острого живота. Всем обследованным пациентам было выполнено комплексное клиническое исследование, включавшее в себя лабораторно-инструментальные методы исследования. Ультразвуковое исследование кишечника выполнялось по специально разработанному поэтапному алгоритму.Результаты. Чувствительность метода составила 68%, специфичность - 80,0%, точность - 72,0%, прогностическая ценность положительного результата -86,0%, прогностическая ценность отрицательного результата - 57,0%.Заключение. Достаточно высокая диагностическая информативность и неинвазивность ультразвукового исследования кишечника позволяют пересмотреть последовательность выполнения инструментальных методов обследования у пациентов с подозрением на острые дивертикулиты и рассматривать ультразвуковое исследование в качестве метода первой линии диагностики

Retention of radiation damage in zircon xenocrysts from kimberlites, Northern Yakutia

We have studied zircon xenocrysts from Mesozoic kimberlites from the Kuoika and Ary–Mastakh fields in Northern Yakutia. Zircon xenocrysts are assumed to originate from crustal rocks. Our SHRIMP (Sensitive High mass Resolution Ion MicroProbe) analyses yielded predominantly concordant U–Th–Pb ages (up to ~ 3570 Ma; Paleoarchean) that clearly predate kimberlite formation. The general U–Th–Pb concordance observed excludes notable disturbance of the zircon xenocrysts U–Th–Pb isotope system during kimberlite ascent and emplacement. In addition, zircon xenocrysts were found to be significantly more radiation-damaged than would correspond to damage accumulation only since the time of kimberlite formation. This observation first indicates that zircon crystals were sampled by the kimberlite magma at comparably shallow depths not exceeding 10–12 km. If, in contrast, zircon crystals originated from deeper levels of the Earth's crust, they would have been exposed to temperatures of 250–300 °C or more. This in turn would have caused long-term thermal annealing of the radiation damage, which was however not observed in our study. Second, our observation contradicts the hypothesis that high temperatures experienced by zircon xenocrysts during kimberlite ascent will cause notable structural reconstitution by short-term thermal annealing. Consequently, zircon crystals cannot have spent more than a few hours at temperatures exceeding ca. 700–800 °C, or more than a few days at temperatures exceeding ca. 500–600 °C. This in turn suggests that (i) temperatures of the ascending kimberlite magmas were rather moderate, and (ii) kimberlite ascent is a comparably short process followed by rapid cooling

МАНТИЙНЫЕ ТЕРРЕЙНЫ СИБИРСКОГО КРАТОНА: ИХ ВЗАИМОДЕЙСТВИЕ С ПЛЮМОВЫМИ РАСПЛАВАМИ НА ОСНОВАНИИ ТЕРМОБАРОМЕТРИИ И ГЕОХИМИИ МАНТИЙНЫХ КСЕНОКРИСТОВ

We have studied variations in the structure and composition of minerals from the pipes of the Yakutian kimberlite province (YKP) in different mantle terranes of the Siberian craton. The study was based on an extensive database, including the microprobe analysis datasets consolidated by IGM, IG, IEC and IGDNM SB RAS and ALROSA and geochemical analysis of minerals performed by LA‐ICP‐MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry). The reconstruction shows layering under the tubes, including 6–7 slab that were probably formed due to subduction; the slabs are separated by pyroxenitic, eclogitic and metasomatic layers and dunite lenses. Transects and mantle profiles across kimberlite fields are constructed. Within the limits of the revealed tectonic terranes, we assume a collage of microplates formed in the early – middle Archean. Extended submeridional structures of the tectonic terranes are not always confirmed at the mantle level. Beneath the Anabar and Aldan shields, the mantle sections show more coarse layers and 3–4 large horizons of dunites with garnet and pyroxene nests separated by ilmenite‐ phlogopite metasomatites and pyroxenites. Terranes representing the suture zones between the protocratons (e.g. Khapchan) are often saturated with eclogites and pyroxenites that may occur as leghthy ascending bodies of magmatic eclogites penetrating through the mantle lithosphere structure (ML). A nearly ubiquitous pyroxenite layer at the level of 3.5–4.5 GPa formed probably in the early Archean with a high heat flux during melting of eclogites and was subsequently traced by plume melts. Within the early Archean protocratons – granite‐greenstone terranes (Tungus, Markha, Berekta, and Sharyzhalgai, ~3.8–3.0 Gyr [Gladkochub et al., 2019], the mantle lithosphere is less depleted and largely metasomatized. The ML structure of the Daldyn and Magan granulite‐orthogneiss terranes is layered with folding revealed in the north‐to‐south sections from the Udachnaya pipe to the Krasnopresnenskaya pipe, which is less pronounced in the latitudinal direction. From the Daldyn field to the Alakit field, there is an increase in the degree of metasomatism, and higher alkalinity of pyroxenes and larger amounts of phlogopite are noted. The most productive Aikhal and Yubileinaya pipes are confined to a dunite core, which is accompanied by a change in the specialization of high‐charge elements Ta‐Nb to Zr‐Hf. Within the limits of the Magan terrane, the thin‐layer structure of the middle and upper parts of the craton keel is replaced with a sharply depleted productive horizon at its base. The mantle of the granite‐greenstone Markha terrrein comprises eclogite (often pelitic) horizons, which suggests subduction of the continental lithosphere or sediments. In the central and northern parts of the Siberian craton, most structures in the mantle are sinking to the west at small angles. The geochemistry features of garnets and pyroxenes from various mantle terranes are considered in detail.Вариации структуры и состава минералов из трубок Якутской кимберлитовой провинции (ЯКП) разных мантийных террейнов Сибирского кратона изучены с использованием обширной базы данных микрозондовых анализов минералов коллектива авторов (ИГМ, ИГХ, ИЗК и ИГБМ СО РАН и «АЛРОСА»), а также геохимических анализов минералов, выполненных методом индуктивно связанной масс‐спектрометрии c лазерной абляцией. Реконструирована слоистость под трубками, образованная 6– пластинами вероятного субдукционного генезиса, разделенными пироксенитовыми, эклогитовыми, метасоматическими горизонтами и линзами дунитов. Построены мантийные разрезы через кимберлитовые поля и протяженные трансекты. В пределах установленных тектонических террейнов предполагается коллаж из микроплит, возникших в раннем –среднем архее, а протяженные субмеридиональные структуры тектонических террейнов не всегда подтверждаются на мантийном уровне. Под Анабарским и Алданским щитами мантийные разрезы более грубослоисты и состоят из 3– крупных горизонтов дунитов с гнездами граната и пироксенов, разделенных ильменит‐флогопитовыми метасоматитами и пироксенитами. Террейны, представляющие шовные зоны между протократонами, как Хапчанский, часто насыщены эклогитами и пироксенитами, которые могут быть протяженными восходящими телами магматических эклогитов, прорывающих структуру мантийной лито‐ сферы (МЛ). Почти повсеместный пироксенитовый слой на уровне 3.5–.5 ГПа, вероятно, возник в раннем архее при высоком тепловом потоке при плавлении эклогитов и в дальнейшем трассировался плюмовыми расплавами. В пределах раннеархейских протократонов: гранит‐зеленокаменных террейнов –Тунгусского, Мархинского, Беректинского, Шарыжалгайского –с возрастом ~3.8–.0 млрд лет [Gladkochub et al., 2019] ман‐ тийная литосфера менее истощена и часто метасоматизирована. Далдынский и Маганский гранулит‐орто‐ гнейсовый террейны имеют слоистую структуру МЛ со складчатостью, проявленной в разрезах с севера на юг от тр. Удачной до тр. Краснопресненской и менее выраженной в широтном направлении. От Далдынского до Алакитского поля растет степень метасоматоза, щелочность пироксенов и количество флогопита. Наиболее продуктивные трубки Айхал и Юбилейная приурочены к дунитовому ядру, что сопровождается сменой специализации высокозарядных элементов Ta‐Nb на Zr‐Hf. В пределах Маганского террейна тонкослоистая структура средней и верхней части киля кратона сменяется резко истощенным продуктивным горизонтом в его основании. Мантия гранит‐зеленокаменного Мархинского террейна содержит горизонты эклогитов (часто пелитового типа), предполагающих субдукцию континентальной литосферы или осадков. В центральной и северной части Сибирского кратона в мантии преобладают структуры погружения на запад с небольшим углом. Рассмотрены особенности геохимии гранатов и пироксенов различных мантийных террейнов