Hasil untuk "Mineralogy"

O. I. Bilous, B. I. Slobodian, V. O. Parfeniuk

Lithium contributes to development of high-tech industries around the globe. This article examines economic prospects of the Ukrainian lithium resources in the context of general trends existing on the world market. An overview and analysis of different aspects such as the world market specifics and current trends, size and ore quality of the European pegmatite deposits, economics of lithium-bearing minerals and commercial requirements to the quality of lithium concentrates are given. Pegmatite deposits prospects are categorized according to their estimated reserves. Main types of lithium-ion batteries are described and their preferences for a particular mineral lithium commodity is characterised. Separately, economic significance of the Ukrainian deposits is shown based on comparison between petalite and spodumene pegmatites. It is shown that under conditions of the same method of lithium processing and extraction, the production costs for one tonne of lithium carbonate from petalite concentrate are 1.7 times higher that from spodumene. At the same time, in terms of mineral grades and ore body extensions petalite deposits are comparable with those of many spodumene ones. The higher costs related to lower lithium content per tonne of concentrate are offset by the petalite’s superior purity during the hydrometallurgical processing stage and the requirement of less waste removal during physical concentration. Two important deposits for the Ukrainian industry, Shevchenkivske and Polokhivske, are compared in light of their economic framework. These deposits have been studied to relative detail and are most attractive for mining. Shevchenkivske deposits is localized in the Priazovskiy megablock, Polokhivske – in Ingulskiy megablock (accordingly, Western Priazovskiy and Central Ukrainian metallogenic districts). The ores of the specified deposits are suitable for production of monomineral concentrates with their further processing to lithium chemical products – lithium carbonate and lithium hydroxide. Mineral resources of these deposits have been estimated to a depth of 500 m from the surface. Considerable prospects and challenges for lithium extraction from the Ukrainian deposits is shown.

Praise Akisanmi

The versatility of natural clay and their ability to adsorb a variety of environmental contaminants present in the water effluents has attracted esthetic concern among environmentalist. These practical applications rely primarily on the diversity of natural clay structure to retain harmful and undesirable substances from the immediate environment. The adsorptive capability of natural clays is related to the fundamental units of the clay-sized crystalline minerals which present in different combinations.

Tomas Želvys, Antanas Brazauskas, Andrej Spiridonov et al.

In recent years it has become commonplace to formalize chemostratigraphic units and identify isotopic zones (chemo­stratigraphic units) from excursions. Stable carbon isotopes have been used in solving stratigraphic problems in the Silurian for more than 30 years. δ13C data supplement other stratigraphic proxies, allowing the subdivision of geological sections and more precise correlation. In this paper we give new δ13C data from the Silurian section of the Jočionys-299 borehole, which is located in eastern Lithuania, crossing shallow marine and lagunal deposits. Based on δ13C variability, the Ireviken carbon isotope excursion (CIE), the Šlilalė CIE, and probably the Valgu CIE have been identified in the investigated section. The Valgu CIE is linked to the lower part of the Švenčionys Formation. The Ireviken CIE is linked to the upper parts of the Švenčionys Formation and the Paprieniai Formation (rise in δ13C values), the Jočionys Formation (moderately stable δ13Ccarb values) and the Verknė Formation (fall in δ13C values). A small negative δ13C shift is documented in the Pabradė Formation. Chemostratigraphy together with biostratigraphic data allow us to correlate eastern Lithuanian lithostratigraphic units (shallow marine environment) with the global Silurian Geochronological Scale more accurately.

Ramachandran Dhavamani, Radovan Pipík, Valentín Sočuvka et al.

The data presented in this paper are related to the research article “Sub-bottom and bathymetry sonar inspection of postglacial lacustrine infill of the alpine lakes (Tatra Mts., Slovakia)” (Dhavamani et al., 2022). An implementation of acoustic sonar protocols provided data for the interpretation of glacigene, glaciolacustrine, postglacial, mass-movement deposits, and geodynamic factors influencing the sedimentation in seven alpine and sub-alpine Tatra Mountains lakes. The field data document the survey track lines of the sonars and allow to identify the location of the geomorphologic phenomena described in (Dhavamani et al., 2022). The laboratory data obtained by micro-CT document the lithology of glaciolacustrine and postglacial lake infill and support the interpretation of sub-bottom sonar record.

Nigel J. Cook, Cristiana L. Ciobanu, Kathy Ehrig et al.

Hematite (α-Fe2O3) and magnetite (Fe3O4) readily accommodate a wide range of minor and trace elements from across the periodic table at up to wt.% concentrations. This prompts the question of whether these common minerals can also host rare earth elements (lanthanides, Y and Sc; REEs)? If so, what is the chemical and physical nature of the elements: are they incorporated into the oxide crystal structures, or do they occur as nanometer-to micron-sized inclusions of discrete REE-minerals? By combining micron-scale petrography and analysis by LA-ICP-MS with nanoscale imaging and energy-dispersive spectroscopy, the relationships between REEs and iron-oxides are addressed in samples from the world-class Olympic Dam Cu-U-Au-Ag deposit, South Australia. Spatially co-existing silician magnetite and hematite from the outer shell at Olympic Dam show stages of interconversion during which REEs are redistributed. REEs are shown to be preferentially incorporated into the magnetite structure, whereas hematite concentrates U, W, and Sn, and contains negligible structurally bound REEs. Abundant, <20 nm-sized uraninite nanoparticles (NPs) are a key host for REEs in hematite. In contrast, hematite from mineralized breccias displays co-precipitation of Fe-oxides and REE-minerals facilitated by discharge of high-volatile fluids. Variation in the shape of chondrite-normalized REE fractionation trends, ranging from concave (hematite containing uraninite NPs) to steeply downwards-sloping (included LREE-dominant phases such as monazite, florencite, fluocerite and cerianite), reflect these differences. Evolving NP mineralogy in the breccias, from in-situ NP formation to an abundance of monazite reflects successive overprinting events and remobilization of elements from solid-solution and subsequent trapping as NPs via coupled dissolution replacement reaction. REE-minerals such as florencite can host nanoinclusions of hematite. Atomic-scale observations, including defects in magnetite and an O-deficient, two-fold hematite superstructure show crystal structural accommodation during Fe-oxide interconversion and inclusion nucleation. Both silician magnetite and hematite show nanoscale muscovite forming along planar defects. Understanding the mineralogical deportment of REEs at Olympic Dam carries potential implications for investigating the viability of REE extraction opportunities from any resource in which Fe-oxides are the dominant component.

یحیی شمس, فرهنگ سرشکی, رضا کاکائی

مساله سرعت بحرانی و تخمین صحیح آن از مسایل پیچیده در طراحی ایمنی تونل‌ها در شرایط اضطراری است. سرعت بحرانی باید به طور دقیق تعیین شود تا بر اساس سناریوی به وقوع پیوسته بتوان شرایط ایمن را در محیط بسته‌ای همچون تونل‌ها ایجاد کرد. کم یا زیاد بودن سرعت بحرانی سبب بروز مشکلاتی در رابطه با افراد حاضر در تونل خواهد شد. شبیه‌سازی کامپیوتری در تمامی مطالعات و آزمایش‌های مرتبط با حریق اهمیت ویژه‌ای دارد. از آنجا که مقدار HRR (آهنگ رهایش گرما) در تخمین سرعت بحرانی بسیار مهم است، هدف این مقاله ارزیابی میزان تاثیر آهنگ رهایش گرما بر مقدار سرعت بحرانی در تونل‌های منحنی است. به این منظور ابتدا یک تونل منحنی برای اعتبارسنجی نتایج عددی حاصل از نرم‌افزار FDS در محیط آزمایشگاهی ساخته شد و سرعت بحرانی به دست آمده برای مدل فیزیکی 90/0 متر بر ثانیه و برای مدل عددی 92/0 متر بر ثانیه بود. پس از اعتبارسنجی داده‌ها، نتیجه‌گیری شد که افزایش HRR سبب افزایش سرعت بحرانی می‌شود، بنابراین بر اساس میزان تغییرات حاصل می‌توان دریافت که این پارامتر در تخمین سرعت بحرانی بسیار حایز اهمیت است، اما این روند تنها بر محدوده مشخصی حاکم است به طوری که تا رسیدن به حریق 15 کیلوواتی سبب افزایش 50 درصدی سرعت بحرانی خواهد شد و چنانکه از ارزیابی نتایج برمی‌آید، در خارج از این محدوده سرعت بحرانی مستقل از مقدار HRR است و افزایش آن تاثیر بالقوه‌ای در رشد یا کاهش سرعت بحرانی ندارد. از سوی دیگر روند افزایش سرعت بحرانی نسبت به آهنگ رهایش گرما در تونل منحنی نسبت به تونل مستقیم، با اختلاف حدودا 10 درصدی، در جایگاه بالاتری قرار می‌گیرد.

V.A. Simonov, V.V. Maslennikov, A.V. Kotlyarov

Studies of melt inclusions in quartz indicate the similarity of acid magmatic systems of massive sulfide deposits in the Urals and Altai-Sayany region. The melts of normal alkalinity corresponding to rhyodacite and rhyolite compositions related to the tholeiitic series are dominant in all the deposits considered. The magmas are characterized by the same type evolution with a decreasing content of main oxides (TiO2 , Al2 O3 , FeO, MgO, CaO, Na2 O, K2 O) and an increasing SiO2 content. Our results show the accumulation of Cu in relatively low-H2 O acidic melts of ancient (Cambrian) deposits of the Altai-Sayany region and low metal contents in the intermediate (Silurian–Devonian) and H2 O-saturated magmas of the Urals. The youngest (Devonian) magmas of Siberia evolve simultaneously along these two directions. The analysis of melt inclusions in quartz suggests that the minimum contents of trace and rare earth elements are characteristic of the SilurianDevonian acid melts of the Urals, with their maximum contents in the youngest (Devonian) magmas and the intermediate contents of ancient (Cambrian) magmatic systems of the Altai-Sayany region. The features of rare and rare earth element patterns in melt inclusions in quartz indicate the similarity of acid magmatic systems of massive sulfide deposits in the Urals and Altai-Sayany region with present-day suprasubduction melts in the ocean-continent transition zones. Computational modeling using data on melt inclusions in quartz confirms our previous conclusions (Simonov, Maslennikov, 2020) that the occurrence of contrasting (basic and felsic) volcanic complexes with massive sulfide deposits in the Urals and Altai-Sayany region is a result of evolution of basaltoid magmas.

N. I. Bezmen, P. N. Gorbachev

Daniel Atencio, Dorília Cunha, André Luiz Ribeiro Moutinho et al.

Abstract The Parauapebas meteorite, third official meteorite discovered in the Brazilian Amazon region, is a “hammer meteorite” which fell on December 9th, 2013, in the city of Parauapebas, Pará State, Brazil. Mineralogy is dominated by forsterite, enstatite, iron, troilite, and tetrataenite. Albite, chromite, diopside, augite, pigeonite, taenite, and merrillite are minor components. Two main clasts are separated by black shock-induced melt veins. One clast exhibits an abundance of chondrules with well-defined margins set on a recrystallized matrix composed mostly of forsterite and enstatite, consistent with petrologic type 4 chondrites. The other clast displays chondrules with outlines blurring into the groundmass as evidence of increasing recrystallization, consistent with petrologic type 5 chondrites. The clasts of petrologic type 4 have a fine-grained texture compared to those of type 5. It is a genomict breccia (indicated by shock melt veins) with the clasts and matrix of the same compositional group, but different petrologic types, H4 and H5. The melted outer crust of the Parauapebas meteorite is comprised of forsterite with interstitial dendritic iron oxide, and is rich in irregular vesicles, which are evidence of the rapid formation of the crust. The type specimen is deposited in the Museum of Geosciences of the University of São Paulo, Brazil.

V.A. Popov

A concentric-zonal texture of mineral aggregate observed in alkali pegmatite of the Vishnevye Mountains was formed as a result of melt-fluid crystallization in a closed system. At the first stage, rare large monazite crystals were crystallized creating wave concentration fields. Allanite-(Ce), bastnäsite-(Ce), chevkinite-(Ce), thoroaeschinite, apatite-(CaF), zircon, calcite and other minerals crystallized in the end of the monazite growth. Feldspars (syntactic intergrowths of albite with Kfeldspar) were dominant in the final stage of crystallization. The change in the composition of meltfluid (magma) from phosphate-silicate to silicate is atypical.

Basem Zoheir, Mohamed Abd El-Wahed, Amin Beiranvand Pour et al.

Multi-sensor satellite imagery data promote fast, cost-efficient regional geological mapping that constantly forms a criterion for successful gold exploration programs in harsh and inaccessible regions. The Barramiya−Mueilha sector in the Central Eastern Desert of Egypt contains several occurrences of shear/fault-associated gold-bearing quartz veins with consistently simple mineralogy and narrow hydrothermal alteration haloes. Gold-quartz veins and zones of carbonate alteration and listvenitization are widespread along the ENE−WSW Barramiya−Um Salatit and Dungash−Mueilha shear belts. These belts are characterized by heterogeneous shear fabrics and asymmetrical or overturned folds. Sentinel-1, Phased Array type L-band Synthetic Aperture Radar (PALSAR), Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER), and Sentinel-2 are used herein to explicate the regional structural control of gold mineralization in the Barramiya−Mueilha sector. Feature-oriented Principal Components Selection (FPCS) applied to polarized backscatter ratio images of Sentinel-1 and PALSAR datasets show appreciable capability in tracing along the strike of regional structures and identification of potential dilation loci. The principal component analysis (PCA), band combination and band ratioing techniques are applied to the multispectral ASTER and Sentinel-2 datasets for lithological and hydrothermal alteration mapping. Ophiolites, island arc rocks, and Fe-oxides/hydroxides (ferrugination) and carbonate alteration zones are discriminated by using the PCA technique. Results of the band ratioing technique showed gossan, carbonate, and hydroxyl mineral assemblages in ductile shear zones, whereas irregular ferrugination zones are locally identified in the brittle shear zones. Gold occurrences are confined to major zones of fold superimposition and transpression along flexural planes in the foliated ophiolite-island arc belts. In the granitoid-gabbroid terranes, gold-quartz veins are rather controlled by fault and brittle shear zones. The uneven distribution of gold occurrences coupled with the variable recrystallization of the auriferous quartz veins suggests multistage gold mineralization in the area. Analysis of the host structures assessed by the remote sensing results denotes vein formation spanning the time−space from early transpression to late orogen collapse during the protracted tectonic evolution of the belt.

Erica P. Suosaari, Stanley M. Awramik, R. Pamela Reid et al.

Hamelin Pool, Shark Bay, Western Australia, is home to the largest and most diverse assemblage of living marine stromatolites, with shapes and sizes comparable to ancient structures. A recent field-intensive program revealed seasonally ephemeral occurrences of modern dendrolitic microbial mats forming in intertidal, low energy settings. Dominated by filamentous cyanobacteria, dendrolitic microbial mats are formed when filaments provide a supporting framework as a result of gliding mobility, to build a shrubby morphology. Dendrolites, known throughout the rock record, refer to macroscopic microbialites with mesostuctures composed of unlaminated arborescent structures called shrubs. In these modern examples, thick filaments of Lyngbya aestuarii form the “trunk” of the bush, with finer filaments of Lyngbya fragilis, Phormidium sp. and Schizothrix sp. forming the “branches” These biologically-influenced dendrolitic structures provide insight into the complex interplay of microbial communities and the environment, broadening our understanding of shrub and dendrolite formation throughout the rock record.

A. Masi, A. Francke, A. Francke et al.

A new high-resolution pollen and NPP (non-pollen palynomorph) analysis has been performed on the sediments of Lake Dojran, a transboundary lake located at the border between Greece and the former Yugoslav Republic of Macedonia (FYROM). The sequence covers the last 12 500 years and provides information on the vegetational dynamics of the Late Glacial and Holocene for the southern Balkans. Robust age model, sedimentological diatom, and biomarker analyses published previously have been the base for a multi-perspective interpretation of the new palynological data. Pollen analysis revealed that the Late Glacial is characterized by steppic taxa with prevailing Amaranthaceae, <i>Artemisia</i> and Poaceae. The arboreal vegetation starts to rise after 11 500 yr BP, taking a couple of millennia to be definitively attested. Holocene vegetation is characterized by the dominance of mesophilous plants. The <i>Quercus robur</i> type and <i>Pinus</i> are the most abundant taxa, followed by the <i>Quercus cerris</i> type, the <i>Quercus ilex</i> type and <i>Ostrya–Carpinus orientalis</i>. The first attestation of human presence can be presumed at 5000 yr BP from the contemporary presence of cereals, <i>Juglans</i> and <i>Rumex</i>. A drop in both pollen concentration and influx together with a <i>δ</i>¹⁸O_carb shift indicates increasing aridity and precedes clear and continuous human signs since 4000 yr BP. Also, a correlation between <i>Pediastrum boryanum</i> and fecal stanol suggests that the increase in nutrients in the water is related to human presence and pasture. An undoubted expansion of human-related plants occurs since 2600 yr BP when cereals, arboreal cultivated and other synanthropic non-cultivated taxa are found. A strong reduction in arboreal vegetation occurred at 2000 yr BP, when the Roman Empire impacted a landscape undergoing climate dryness in the whole Mediterranean area. In recent centuries the human impact still remains high but spots of natural vegetation are preserved. The Lake Dojran multi-proxy analysis including pollen data provides clear evidence of the importance of this approach in paleoenvironmental reconstruction. Cross-interpretation of several proxies allows us to comprehend past vegetation dynamics and human impact in the southern Balkans.

Şule GÜRBOĞA, Özgür AKTÜRK

Elmalı Havzası, Antalya iline yaklaşık 120 km uzaklıkta bulunan Elmalı ilçesi ve birçok köy yerleşiminin bulunduğu, güneybatı Türkiye’nin genişlemeli neotektonik bölgesi içinde yer alan güncel depolanma alanlarından biridir. Bu tür alanlar temel kayalardan güncel çökellere kadar olan süreci kaydetmeleri nedeniyle jeolojik tarihçenin anlaşılması için önemli veriler sunmaktadır. Bu nedenle, havzaya güncel şeklini ve özelliklerini kazandıran yapıların tespiti ve değerlendirilmesi deformasyon fazlarının elde edilmesi amacıyla kullanılmaktadır. Bu amaca yönelik olarak; (a) çalışma alanına ait 1/25.000 ölçekli jeolojik harita ve yapılara ait verilerin ortaya konması, (b) havza kenarını sınırlayan faylara ait aktivite ve deformasyon bilgisinin araştırılması, (c) bölgede meydana gelebilecek ortalama 6.5 büyüklüğünde bir deprem sonucunda maksimum yer sarsıntı miktarı (peak ground acceleration), ve (d) sayısal yükseklik modeli kullanılarak havzaya ilişkin morfometrik analizlerin sonucunda havzayı kontrol eden tektonik yapılar araştırılmıştır. Bu çalışmadan ve önceki çalışmalardan elde edilen verilerin birlikte değerlendirilmesi sonucunda ortaya çıkan sonuçlar, Elmalı Havzası’nın çok sayıda deformasyon yapısına ve aktif faylara sahip olduğunu göstermektedir. Ayrıca, morfometrik indeksler havzanın batı sınırının doğu sınırına göre daha yüksek oranda yükselim hızına sahip olduğunu ortaya koymuştur..

Vsevolod N. Anfilogov, Artur A. Krasnobaev, Vyacheslav M. Ryzhkov

Some problems appeared after determinations of the old age of dunite material in the ultrabasite massifs of the folded regions and zonal massifs on the continental plateaus: 1) the problem of equilibrium of zircon and olivine + pyroxene composition in ultrabasite; 2) the problem of different age of zircon in every massif of ultrabasite and the way of the zonal zircon crystal formation; 3) the problem of the origin of the most old dunite material in ultrabasite massives; 4) the problem of formation of zonal zircon crystals in dunite. Experimental investigation of phase equilibrium in MgO-SiO2-ZrO2 system showed that zircon able to crystallize coincidentally with olivine and pyroxene. It was found that zircon in dunite is stable to 1450°C. Zircon is replaced to baddeleite at more high temperature. It is shown that the zonal zircon crystal can be formed by its transformation to baddeleite and the inverse process. The mechanism of dunite material accumulation at partial melting of mantle peridotite and possible way of transport of the residue dunite to the surface in diaper form are considered. The difference between ultrabasite of the Platinum belt of the Urals and Alpine type of ultrabasite is discussed. It is proposed that massifs of the Alpine type ultrabasite were intruded сlose to the surface where they interacted with porous water. The interaction of hyperbasites with the pore fluid will lead to their intensive serpentinization, the redistribution of chromium and its concentration in the form of ore bodies.

Jaqueline Alves de Almeida Calábria, Stela Dalva Santos Cota, Ana Cláudia Queiroz Ladeira

Abstract The preferred option for disposal of short-lived low and intermediate level radioactive wastes is a near surface disposal facility in which soil is one of the barriers that avoid radionuclide migration outside the controlled area. For construction of that kind of facility, concrete is widely used, and its interaction with water induces its degradation, resulting in a high pH solution. The alkaline solution may affect the near-field environment of radioactive waste repositories, including the soil, promoting mineralogical alterations that result in significant changes in key properties of materials, compromising their performance as safety components. In this study, a sample of a Brazilian Typic Rhodudult soil, previously investigated concerning its performance for Cs sorption, was subjected to interaction with the alkaline solution for 24 h and for 7, 14, and 28 days in order to evaluate the impact on its chemical, mineralogical, and sorption properties. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), atomic absorption spectrometry (AAS), scanning electron microscopy (SEM), and electron microprobe analysis were performed before and after each alteration period. Results indicated dissolution of minerals, such as kaolinite and quartz, associated with incorporation of K and Ca from the alkaline solution, likely resulting in the formation of hydrated calcium silicate phases (CSH), which are expected to be worse sorbents for alkaline elements (e.g., Cs) than the original minerals. The Kd values for Cs in the altered samples also decreased according to the alteration period, demonstrating that alkaline interaction effectively modifies the soil sorption properties for Cs.

T. K. Burakhovich, A. M. Kushnir, I. Yu. Nikolaev et al.

Spatial-temporal pattern of distribution of geomagnetic variations and the electric field on the Earth’s surface was obtained as a result of the modern experimental observations conducted in 2007—2013 along 9 profiles (48 points) by the methods of magnetotelluric sounding (MTS) and magnetovariation profiling (MVP). These profiles cross various geological structures of the Crimean region. It is possible to estimate the value of the electrical conductivity and vertical and horizontal geoelectric structure. The processing of these data is done using modern software system PRC_MTMV (author Varentsov Iv. M.) that provides the common noise-protected evaluation of the impedance, tipper, horizontal magnetovariation response according to the synchronous MT/MV records. The main result of qualitative interpretation of geoelectric research is the detection of high conductivity regions in the Earth's crust and upper mantle of the Crimea, that are characterized by the variations of conductivity, depth and configuration. They characterize the various geological structures differently. The subvertical conductive zones often coincide with the fault structures, most of these objects are confined to the suture zones between tectonic elements such as the East European platform and the Scythian plate, the Scythian plate and the Crimea mountain, North and South Kerch zone. This fact may reflect the high permeability of the suture zones for deep fluids in the process of their formation. Some high conductivity anomalies are well-described in the literature and are known. For example, the unique Tarhankut conductivity anomaly, located not only on the eponymous peninsula of Crimea, but also under the water area of the north-western part of the Black sea. This anomaly was detailed and precised and involves a complex multi-level deep structure of the region. In addition, the structurally complex conductivity anomaly is assumed in the Sivash graben and the Kerch Peninsula. Although the qualitative interpretation of the experimental data of magnetotelluric sounding (MTS) and magnetovariation profiling (MVP) provides the inconsistent understanding of the depth distribution of the Crimean region electrical conductivity, the combination of these methods allows to construct the model of the resistivity distribution within a three-dimensional environment much more accurately and adequately to the observed experimental data.

Edward eJones, Balwant eSingh

M. E. Teruggi

R. T. Dodd