Search

Contexte : l'angioplastie mécanique par ballonnet dans le cadre du vasospasme cérébral consécutif à une hémorragie sous‐arachnoïdienne d’origine anévrismale (HSAA) présente des limites, notamment l'occlusion transitoire du vaisseau sanguin spastique. Le Comaneci® (Rapid Medical, Yokneam, Israël) est un dispositif approuvé par la FDA pour l'assistance temporaire à l'embolisation par coils et, depuis peu, pour le traitement du vasospasme réfractaire symptomatique distal. Nous avons voulu évaluer la faisabilité, l'efficacité et les complications concernant l'angioplastie Comaneci® dans le traitement du vasospasme distal réfractaire après HSAA. Matériels et méthodes : il s’agit d’une analyse monocentrique rétrospective d'une série prospective de 18 patients inclus entre avril 2019 et juin 2021 ayant subi une HSAA compliquée d’un vasospasme symptomatique réfractaire au traitement médical traités par angioplastie distale mécanique assistée par Comaneci®‐17. Les résultats angiographiques immédiats, les complications liées à la procédure et les résultats cliniques ont été évalués. La fiabilité des scores a été déterminée à l'aide du coefficient de corrélation intra‐classe. Résultats : l'angioplastie distale assistée par Comaneci® a été réalisée chez 18 patients correspondant à 31 artères cibles. Tous les segments antérieurs distaux étaient facilement cathétérisables par le dispositif Comaneci®‐17. Une amélioration du vasospasme après angioplastie mécanique a été visualisée pour 22 artères distales (71%) (κw 0,73, 95%CI 0,69‐0,93). Une récidive du vasospasme est survenue chez 3 patients (16,67%) et un infarctus cérébral retardé chez 3 patients (16,67%) avec un délai moyen entre le début des symptômes et le suivi par imagerie (IRM/CT) de 32,61 (±8,93) jours, κw 0,98 (95%CI 0,88‐1). Conclusion : cette première expérience suggère que l'angioplastie mécanique distale réalisée à l’aide du dispositif Comaneci®‐17 dans le cadre du vasospasme réfractaire après HSAA semble être faisable et efficace.Objectif : évaluer les résultats cliniques préliminaires du traitement des kystes mucoides intra-osseux par injection percutanée de ciment phosphocalcique et rechercher la bio-intégration du ciment.Matériel et méthodes : étude rétrospective monocentrique menée sur 7 patients (de 41 ans d’âge moyen) avec un diagnostic de kyste mucoïde intra-osseux para-articulaire, douloureux et résistant aux antalgiques, traités par injection de ciment phosphocalcique percutanée sous guidage combiné tomographique et fluoroscopique. Toutes les lésions sont situées sur des os porteurs des membres inférieurs (aile iliaque, plateau tibial, talus, calcanéus). L'évaluation de la douleur a été évaluée grâce à l'échelle verbale simple (EVS) avant le traitement, pendant le geste sous anesthésie locale, à 6 semaines après le traitement et pour 5 patients lors d’une consultation en 2021 associé à la réalisation d’un scanner et d’une IRM entre 6 mois et 4 ans après la procédure (moyenne 31 mois). Résultats : le suivi montre une satisfaction de 100 % des patients avec une diminution significative au cours du temps post-traitement. Aucune récidive douloureuse n’est apparue à distance. On constate une bio-intégration partielle du ciment phosphocalcique chez 3 patients dont les procédures sont les plus anciennes (> ou = à 3 ans).Conclusion : notre étude suggère que l'injection de ciment phosphocalcique par voie percutanée dans les kystes mucoïdes intra-osseux para-articulaire est une technique percutanée applicable pour le traitement antalgique des kystes mucoides intra-osseux para-articulaires.

The article describes the establishment of the location of agate geodes using the GPR method in the area of the Simota gully (Lesser Poland Voivodeship). Agates (a multicolored variety of gemstone of chalcedony group) have multifaceted values that informed their study. Traditional methods of geode location are less reliable, hence the attempt to use the GPR method. Measurements were taken at two study test sites with subsurface geology of weathered melaphyre and pyroclastic deposits using a GPR system (ProEx). A high-frequency antenna (1.6 GHz) was used along with the pre-established profiles of lengths of 6-m and 10-cm intervals. Furthermore, simple soil tests using the soil sampler tool were made prior to the GPR measurement. The GPR results show significant high attenuation of the electromagnetic energy interpreted to be due to clay components of the regolith. Advanced signal processing procedures (such as the attribute of the signal) were used on the data for better enhancement that aided interpretation. Other anomalies depicted on the radargrams were thought to be the presence of roots, pieces of melaphyres-targeted agates. Furtherance to ascertain the reflection coefficients as recorded on the GPR data, in situ samples (root pieces, melaphyres, agates) taken were tested in the laboratory for electric permittivity property. Based on the interpretation results, several agate geodes were dug out from the ground.

An exposure of agate geode and nodules in Mount Conner, Sabah, provides an essential aspect to the geological formation in Semporna. This paper briefly report results from petrography analyses on the agate geode and nodules and its significance to the volcanic rocks and sedimentary rocks formation in Mount Conner. The geode and nodules can be divided into agate, and nodules and most of them are sub-rounded. Nodules are usually small in size and display brownish colour. It commonly occurs in volcanic rocks (dacite and rhyolite) and contained amygdale filled by secondary mineral such as microcrystalline and macrocystalline quartz. In contrast, sedimentary rocks in Mount Conner contain both nodules and geodes, which nodules shows similar characteristic with nodules in volcanic rocks and geodes contained empty vesicles or spaces surrounded by colourless to milky white quartz crystals. Both geode and nodules exhibit conchoidal fracture, while geode shows vesicle features and nodules in volcanic rocks show amygdale texture. The formation of geodes and nodules in Mount Conner might as result of precipitation under low temperature from hydrothermal solution.

Subaqueous gypsum (CaSO4·2H2O) crystals are relatively common in epithermal systems where sulfide ore deposits are present. The Giant Geode of Pulpí (Almería, SE Spain) hosts some of the largest (up to 2 m in length) subaqueous gypsum crystals discovered to date. Here, we present the first U-series ages of its crystals and reconstruct the oxygen and hydrogen isotopic composition (δ18O and δ2H) of the Pulpí paleo-aquifer from which the crystals formed by using stable isotopes of gypsum hydration water. We successfully dated the onset of gypsum precipitation in the Geode at 164 ± 15 ka. However, the extremely low U concentration (11 ppb) and relatively high detrital Th content (230Th/232Th 3.2) hinder accurate dating other gypsum samples. The δ18O and δD values of the paleo-aquifer during the growth of the crystals aligned with the local meteoric water line, suggesting that the sulfate-enriched mother solution consisted of meteoric water that recharged the aquifer during that period. The mean isotopic composition of the Pulpí paleo-aquifer (δ18O = −6.5 ± 0.1‰ and δ2H = −42.3 ± 0.5‰) during the formation of the crystals was similar to the current groundwater in this area (δ18O = −6.1 ± 0.8‰, δ2H = −42 ± 6‰). The isotopic differences observed in samples collected from distinct locations and in individual crystals were probably related to changes in the isotopic composition of the aquifer, as a consequence of varying climate that impacted on the isotopic composition of rainwater during thousands of years in this region. Our results indicated that subaqueous selenite crystals may be useful for paleo-hydrological reconstructions. However, improving the current analytical techniques for dating gypsum with low U concentrations will be essential to obtain accurate and reliable records from Quaternary gypsum cave crystals in the future.

The Parana Volcanic Province follows Siberia as the second largest in the continents and offers a unique opportunity to study the hydrothermal relationship between basalt-rhyodacite lavas and buried erg-turned aquifer in an intraplate setting. Injected sand fluidized after basalt sealing and was succeeded by amethyst and agate geode opening and filling. Excellent exposures in the Herveiras cuesta, southern Brazil, allow the comparison of processes over long distances (1500 km) in the volcanic group. Fieldwork and basalt chemistry led to the identification of three hydrothermal processes-amygdales filling (H1), sand injection (H2) and amethyst geodes formation (H3). Sand injection was triggered by high temperature (150 ℃) and seismicity. These low-temperature processes identified in the Herveiras cuesta demonstrate the homogeneity of relationships between the paleoerg, giant aquifer and intraplate volcanic rocks across the volcanic province.

The study aims to differentiate the silica forms stratified in the siliceous geodes using infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The water content (total water, H2Omol and Si-OH) in SiO2. nH2O forms are used as the fingerprint for the different varieties of the silica morphs. For this reason, an irregular botryoidal spherical shape siliceous geode formed from alternative silica forms collected from Early–Late Eocene carbonate sediments of the Ratga Formation located in the Western Desert of Iraq were mineralogically investigated. The FTIR and XRD as authoritative tools that have been used together with the water content to enhance the distinction between crystalline and non-crystalline silica forms. Quartzine, quartz, chalcedony opal-A, opal-C, and opal-CT have been identified in different layers of geode in addition to calcite lining the geode center.

Large amounts of stone wastes are accumulated alongside different exploiting mines of amethyst geodes in south Brazil, which are becoming an unsustainable environmental issue. For an adequate use of hydrothermal basalt in agriculture as soil remineralizer, it is fundamental to know the material's mineralogy and geochemical variability. This study aims to evaluate the mineralogical and geochemical variability of the basalt from five mines at two positions (near and far from the geodes) in different size fractions to discuss their potential use in agriculture. X-ray diffraction (XRD), X-ray fluorescence (XRF) and petrographic analyses of thin sections were used. Petrographic and mineralogical analyses showed similar compositions for the rocks, consisting of plagioclases, pyroxenes, and opaque minerals with apatite as an accessory mineral. The rock samples located near the amethyst geodes presented slightly higher clay mineral contents than the distant ones. The clay mineralogy was composed of smectite and celadonite. The subfractions preserved the characteristics of the original material. Small geochemical and mineralogical variations were observed in the hydrothermal basalts regardless of the positions and the fraction sizes studied. These characteristics confer this material a high potential for use in agriculture as a soil remineralizer. This approach contributes both to solving an environmental issue associated with geode exploitation and to create an alternative for soil fertilization.

Rheumatoid arthritis is characterized by multiple chronic arthritis subsequently inducing joint destruction. Although subchondral geode is a well-known feature of high-disease activity, a large geode is rare. Moreover, the treatment effect of biologic agents in the repair of large geode has not been reported. The present report shows the significant effect of interleukin-6 receptor blocker, tocilizumab, in repairing the large geode in the left humeral lateral epicondyle. This case implies that tocilizumab might be an effective treatment in patients with rheumatoid arthritis even with large geode.

The world-class giant gold province (>4000 t) in the Jiaodong Peninsula has attracted global attention and extensive studies for decades. However, most of the works have been focused on the western Zhaoyuan-Laizhou and eastern Muping-Rushan gold metallogenic belt, leaving the middle Penglai-Qixia belt largely unexplored. The Hushan gold deposit in the Penglai-Qixia belt shows a unique two-stage gold mineralization, i.e., an early-stage pyrite-sericite-quartz altered-rock type mineralization and a late-stage pyrite-pyrrhotite vein type mineralization. Hydrothermal monazite coexisting with Au-bearing pyrite is observed in the early-stage mineralization. The widespread “circular zoned” metasomatic relict structures indicate that monazite was formed by the strong interaction between (Ca, P, REE)-rich fluids and feldspars (plagioclase and K-feldspar). Therefore obtained in-situ U-Pb age of 120.0 ± 3.1 Ma for the “pure” monazite without mineral inclusions (such as feldspars) can represent the timing of the early-stage gold mineralization. The in-situ monazite e Nd (t) (t = 120 Ma) values vary from −20.6 to −18.4, well corresponding to Nd isotopes of the late Jurassic Linglong granite. It is inferred that the REE-rich components in the ore-forming fluids were extracted during the process of primary mineralizing fluids passing through the lower Linglong granite body, and that the Nd isotopic compositions were altered due to the strong fluid-rock interaction. In this regard, Linglong granite contributes some ore-forming materials to the mineralizing fluids during fluid-rock interaction. The early-stage altered-rock type gold mineralization indicates a compressional (closed) ore-forming system, whereas the late-stage pyrite-pyrrhotite vein type mineralization and the occurrences of fracture, geode and hole in the ore samples reflect an extensional (open) ore-forming system. The presence of barite and magnetite in the late-stage mineralization also suggests an increase of oxidation state during the process. Furthermore, pyrites in the late stage generally have lower δ 34 S values (5.69–6.98‰, av. = 6.47‰) than pyrites in the early stage (δ 34 S values = 7.06–7.85‰, av. = 7.42‰), which can also be well explained by the increase of oxidation state. Therefore, the Hushan gold deposit uniquely records a metallogenic environmental transition from compressional, reduced to extensional, oxidized at ∼120 Ma. In addition, the mineralizing fluids with higher oxidation state in the late-stage is supposed to superimpose on the early-stage mineralization, dissolve and rework previously crystalized pyrite to form the high-grade gold mineralization. Unlike the gold deposits in the western and eastern belts, the Hushan gold deposit temporally preserves two types of mineralization in one single deposit, as a response to regional stress field transition.

Agates are unable to be reproduced in a laboratory environment, and hence the mechanism of their formation remains unknown. Present hypotheses regarding genesis are thus, inevitably, speculative. We describe novel experiments, at room temperature and pressure, producing banded amorphous silica gel ( via a sol–gel transition) whose morphology is compared to that of agates. In addition, macro- and microscopic examination of agates from several sites revealed some distinctive physical features: surface pitting, indentations of the agate bands, the variation in morphologies of the bands, thinning and narrowing of the bands around the indentations and the escape tubes, shapes of the coloured impurities and persistence of the sharp angle of the bands at sector boundaries. These observations and experimental data lead us to conclude that agates can be formed in four stages: sol–gel transition with concomitant band formation, formation of escape tubes, rapid crystallization from multiple nucleation sites and late dissolution/recrystallization of the inner layers.

Tumuli are a common feature of pahoehoe basaltic flows, interspersed with pits, and furnished the necessary volume of rock in the Parana volcanic province for hydrothermal alteration and ballooning to form large cavities (1–2 m common). Filling by amethyst and other minerals resulted in the largest world deposit of geodes, Ametista do Sul. The flat-lying fracture positioned 1 m below the 2–3 m thick geodic level crosses the plateau and is a major guide for exploration and gallery opening. The geodes are limited on the top by the platy joint layer, which is covered by an auto-breccia with undulating lower limit. This wave mimicks and is internal to the structure of tumuli and pits at the surface. This field-oriented survey of galleries selected out of 300 active mines resulted in the description of the internal structure of the remarkable Veia Alta pahoehoe flow, in addition to observations in Uruguay.

Geode or subchondral bone cyst is a lytic lesion in the peri-articular area and this condition is seen as a cyst or cyst erosion in a bone end. Basically, a cyst is lined by epithelium but subchondral bone cyst is not lined by epithelium. Subchondral bone cyst are common in various articular diseases.

A variety of spheroidal sedimentary structures occur in the American Midwest where they have been regarded as great curiosities. These rounded objects differ so much from the flat and layered rocks...

Open spaces in rocks present places for crystals to grow unimpeded and thus host most of the well-formed crystals desired by mineral collectors. There are many different mechanisms by which open sp...

Temperature fluctuations, maybe from climate or maybe from geothermal systems, amplified a natural process that grew the crystals.

The Geode of Pulpi (Almeria, Spain) is an ~11 m3 ovoid cavity, the walls of which are covered with meter-sized idiomorphic and highly transparent gypsum (CaSO4¿2H2O) crystals. We performed a thorough study based on field work, and petrographic and geochemical data collection, which aimed to reconstruct the geological history leading to the formation of this geode. The geode is hosted in mineralized Triassic carbonate rocks with a discontinuous mineral sequence from iron-carbonates and barite to celestine and finally gypsum (microcrystalline and selenite). Data from fluid inclusions show that barite precipitated above 100 °C, celestine at ~70 °C, and gypsum below 25 °C. All ¿34S sulfate phases fall between Triassic and Tertiary evaporite values. Barite and gypsum, either microcrystalline or large selenite crystals, show variable ¿34S and ¿18O compositions, whereas celestine and centimetric selenite gypsum have homogeneous values. We propose that the growth of the large selenite crystals in the Geode of Pulpi was the result of a self-feeding mechanism consisting of isovolumetric anhydrite replacement by gypsum at a temperature of 20 ± 5 °C, episodically contributed by a ripening process enhanced by temperature oscillations due to climatic change. © 2019 The Authors., Financial support was provided by Projects CGL2010– 16882 and CGL2010–12099-E (Ministerio de Educación y Ciencia [MEC]) and CGL2016–78971-P (MEC). We acknowledge logistic support from Magí Baselga, the Town Council of Pulpi, and the Junta de Andalucia (Proyecto de Excelencia RNM 5384). We are grateful to Yves Krüger for his assistance during monophase inclusion measurements. Van Driessche acknowledges funding from the French national program EC2CO–Biohefect, SULFCYCLE.

A new frontier of amethyst geode deposits (amethyst, agate, gypsum, calcite and zeolites) driven by the prospective guide termed silica gossan may change the metallogenetic scenario previously known in the Parana volcanic province. Silica gossans, which are related to basalt, basaltic andesite and rhyodacite, occur throughout this province. In this study, we focus on the Ametista do Sul mining district, Rio Grande do Sul, Brazil, the largest producer of amethyst geodes in the world (400 t/month). In this district, a silica gossan occurs at the top of the Coogamai flow above the Mina do Museu. This basalt (47.9 wt.% SiO 2 ) flow belongs to the intermediate-Ti Paranapanema magma type (2.25 wt.% TiO 2 and Ti/Y = 416) exhibiting columnar jointing. The gossan as prospective guide displays polygonal shape associated with the enrichment of clay minerals at the surface, the concentration of iron oxides and the presence of silicified sandstones. In addition, marshes with ponds and a change in surface color (ocher to brownish) and vegetation type were observed. A gamma spectrometry survey at the Mina do Museu silica gossan showed negative anomalies in %K, eU and eTh above the amethyst deposit with values of 55 counts per second (cps) outside the silica gossan and 43 cps within it. These anomalies are caused by hydrothermal events and subsequent weathering of the silica gossan. Bulk rock analyses of the silica gossan demonstrate a loss on ignition up to 1.8 wt.% whereas this value is around 0.5 wt.% for rocks outside the silica gossan. SiO 2 , K 2 O, MgO, CaO and Na 2 O display negative correlations with loss on ignition. X-ray diffraction proved the presence of smectites and kaolinite in the soil on the silica gossan. In addition, dioctahedral and trioctahedral interlayered smectites were identified. Mg-smectite is present in the silica gossan whereas K-smectite occurs in the Coogamai flow.

Thousands of silica gossans are exposed at the top of the Lower Cretaceous basalt hills in the Parana volcanic province, strongly indicating the presence of calcite, amethyst and agate geode deposits along with native copper mineralization. The Embrapa silica gossan in the northwestern portion of the province (Campo Grande region) is an excellent example of such novel geological structure in the continental flood basalts. This silica gossan has a size of 450 × 350 m standing out as a treeless area in the densely wooded savanna and makes part of the stratigraphy of six basalt flows of Paranapanema intermediate-Ti chemical type. The base of the volcanic column is constituted by two Pitanga types and the overlying column is Paranapanema type. Every basalt flow has a silicified sand layer or breccia at the top and these are fed by abundant sand dikes. The Anel Viario Norte (AVN) flow is the most intensely altered by hydrothermal fluids producing voluminous secondary calcite infillings in the amygdales and fractures. In this region the basalts contain higher copper content than the average of the volcanic province. The studied silica gossans display negative anomalies in gamma spectrometry as a response to K, U and Th depletion during alteration. We propose a new exploration methodology by observing GoogleEarth images complemented with field studies and geochemistry to readily locate favorable areas for amethyst and agate geode deposits and native copper mineralization.