Hasil untuk "Mineralogy"

S. Graeser, S. Graeser, D. Topa et al.

<p>Spaltiite is a new thallium sulfosalt with the ideal formula of Tl<span class="inline-formula">₂</span>Cu<span class="inline-formula">₂</span>As<span class="inline-formula">₂</span>S<span class="inline-formula">₅</span>. It was found on a dump of the famous mineral locality Lengenbach (Binntal, Canton Valais, Switzerland). A small piece of pure white Triassic dolomite belonging to the Penninic Monte Leone Nappe hosts three euhedral long prismatic to lath-like spaltiite crystals, each approximately 2 mm in length but only <span class="inline-formula">∼0.2</span> mm thin. The hand specimen contains small quantities of pyrite, drechslerite and hatchite. The spaltiite crystals are greyish to black in colour and extremely soft. The Mohs' hardness is 1.5–2 (VHN<span class="inline-formula">₁₅</span> ranges from 30 to 65, mean 47 kg mm<span class="inline-formula">⁻²</span>). The mono-clinic crystals have a perfect cleavage parallel to <span class="inline-formula"><i>{</i>100<i>}</i></span>, which produces minute and plastic slabs. Reflectance measurements in air yield the following <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>R</mi><mi mathvariant="normal">min</mi></msub><mo>/</mo><msub><mi>R</mi><mi mathvariant="normal">max</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="52pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="d02c9cdc34358548d654e324c6929bce"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00001.svg" width="52pt" height="14pt" src="ejm-38-27-2026-ie00001.png"/></svg:svg></span></span> values based on the standard wavelengths (Commission on Ore Mineralogy, COM): 27.0 % <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="539a58614ea8688159b8effbc6d3da8d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00002.svg" width="8pt" height="14pt" src="ejm-38-27-2026-ie00002.png"/></svg:svg></span></span> 32.6 % (470 nm); 26.8 % <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M15" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="7572a9d7afeaa92ba0e8bb6f686362bd"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00003.svg" width="8pt" height="14pt" src="ejm-38-27-2026-ie00003.png"/></svg:svg></span></span> 32.1 % (546 nm); 26.0 % <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M16" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="c6f00d13d95b9183e3e2526db4298e27"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00004.svg" width="8pt" height="14pt" src="ejm-38-27-2026-ie00004.png"/></svg:svg></span></span> 31.1 % (589 nm); and 24.8 % <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M17" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="a3a809672b156f3719eee3cbaf593ee5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00005.svg" width="8pt" height="14pt" src="ejm-38-27-2026-ie00005.png"/></svg:svg></span></span> 29.3 % (650 nm). Averaged electron-microprobe analyses (<span class="inline-formula"><i>n</i>=10</span>) gave (in wt %) Tl 47.41(19), Cu 15.46(12), Ag 0.15(6), As 17.36(14), Sb 0.41(5) and S 19.20(8), total 99.99(32). The empirical formula is Tl<span class="inline-formula">_1.94</span>Cu<span class="inline-formula">_2.04</span>Ag<span class="inline-formula">_0.01</span>As<span class="inline-formula">_1.95</span>Sb<span class="inline-formula">_0.03</span>S<span class="inline-formula">_5.03</span>, calculated based on 11 apfu. The large crystals exhibit a remarkably homogeneous composition. Spaltiite crystallises in space group <span class="inline-formula"><i>P</i></span>2<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M26" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi/><mn mathvariant="normal">1</mn></msub><mo>/</mo><mi>c</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="8612d9a728947694db06929c712e1bc6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00006.svg" width="20pt" height="14pt" src="ejm-38-27-2026-ie00006.png"/></svg:svg></span></span> (<span class="inline-formula"><i>a</i>=15.791(8)</span>, <span class="inline-formula"><i>b</i>=10.000(5)</span>, <span class="inline-formula"><i>c</i>=6.323(3)</span> Å, <span class="inline-formula"><i>β</i>=99.25(8)</span>°, <span class="inline-formula"><i>V</i>=985.5(8)</span> Å<span class="inline-formula">³</span>). The crystal structure was determined from single-crystal X-ray diffraction data (<span class="inline-formula"><i>R</i>₁=12.18</span> % for 4753 data, with F<span class="inline-formula">_<i>o</i>&gt;4<i>σ</i></span> (F<span class="inline-formula">_<i>o</i></span>) and 101 variable parameters). Spaltiite exhibits a pronounced layered atomic arrangement: two polar Cu–As layers in (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M36" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="c9e563c04ef0bd34b79af4cb2e191aff"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00007.svg" width="20pt" height="14pt" src="ejm-38-27-2026-ie00007.png"/></svg:svg></span></span> <span class="inline-formula"><i>y</i> <i>z</i></span>) and (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M38" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">3</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="30b07de17d2d38641add3bc8b83fb127"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00008.svg" width="20pt" height="14pt" src="ejm-38-27-2026-ie00008.png"/></svg:svg></span></span> <span class="inline-formula"><i>y</i> <i>z</i></span>), respectively, are related by inversion symmetry. Sandwiched between them are the Tl atoms. These two layers are centred in (0 <span class="inline-formula"><i>y</i> <i>z</i></span>) and (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M41" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">2</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="383b6ebff07a68cc6459808254fe9b9c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00009.svg" width="20pt" height="14pt" src="ejm-38-27-2026-ie00009.png"/></svg:svg></span></span> <span class="inline-formula"><i>y</i> <i>z</i></span>), centrosymmetric but topologically and crystallographically distinct. The eight strongest intensities in the X-ray powder diagram are [<span class="inline-formula"><i>d</i></span> in Å (intensity) <i>hkl</i>]: 3.914 (40) 021; 2.988 (63) 510; 3.496 (45) 311; 2.869 (45) <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M44" display="inline" overflow="scroll" dspmath="mathml"><mrow><mover accent="true"><mn mathvariant="normal">5</mn><mo mathvariant="normal">‾</mo></mover><mn mathvariant="normal">11</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="19a87194d2a60b38e097aed50cc1c11c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00010.svg" width="20pt" height="13pt" src="ejm-38-27-2026-ie00010.png"/></svg:svg></span></span>; 2.652 (36) <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M45" display="inline" overflow="scroll" dspmath="mathml"><mrow><mover accent="true"><mn mathvariant="normal">3</mn><mo mathvariant="normal">‾</mo></mover><mn mathvariant="normal">31</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="d70d08c65379357dd1f9af3d89df6479"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00011.svg" width="20pt" height="13pt" src="ejm-38-27-2026-ie00011.png"/></svg:svg></span></span>; 3.646 (34) <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M46" display="inline" overflow="scroll" dspmath="mathml"><mrow><mover accent="true"><mn mathvariant="normal">2</mn><mo mathvariant="normal">‾</mo></mover><mn mathvariant="normal">21</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="ef82265a0ec277239d16659eb9c33232"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-38-27-2026-ie00012.svg" width="20pt" height="13pt" src="ejm-38-27-2026-ie00012.png"/></svg:svg></span></span>; 2.506 (29) 040; 2.762 (26) 202. The name of the new mineral originates from the nickname “spalti”, which was used during laboratory studies, illustrating the extremely pronounced cleavage (in German, “<i>spalten</i>” means cleave).</p>

Guolai Li, Zeina Naim, Luis Gibert et al.

Abstract This study examines the climatic controls on dolomite precipitation through a multiproxy investigation of a carbonate‐rich sediment core from Salinas Lake, a hypersaline playa in Alicante, south‐eastern Iberia. The ~120,000 year record captures depositional cycles and palaeoenvironmental changes driven by late Pleistocene to Holocene climate variability. Integrated analyses of sedimentology, lithology, geochemistry (elemental concentrations, total organic carbon, stable carbon and oxygen isotopes), scanning electron microscopy, microbial community characterisation and palynology reconstruct lake hydrology and its influence on carbonate mineralogy. The sediment succession is marked by alternating calcite‐ and dolomite‐rich intervals, with dolomite crystals displaying morphological evolution from spherical to rhombohedral forms with depth. Stable isotope signatures (δ13C: −6.5‰ to −2.4‰ VPDB; δ18O: −2.3‰ to +4.9‰ VPDB), alongside microbial structures such as extracellular polymeric substances (EPS) and internal crystal voids, suggest a biologically mediated precipitation mechanism. These mineralogical shifts closely correspond to rapid hydrological changes driven by Dansgaard–Oeschger climate oscillations, with dolomite formation favoured under arid, evaporative conditions that concentrate Mg and Ca ions and promote microbial mat development. Halophilic microbial communities, capable of catalysing carbonate precipitation, probably enhance dolomite nucleation and growth through EPS production and geochemical modulation. This work underscores the complex interplay between climate, hydrology, microbial activity and sedimentary mineral formation, providing new insights into the longstanding ‘dolomite problem’ within sedimentary environments.

D. Spengler, M. Koch-Müller, A. Włodek et al.

<p>A total of 10 western Norwegian eclogites, whose mineral chemistry records metamorphism of up to 850 <span class="inline-formula">°C</span> and 5.5 <span class="inline-formula">GPa</span>, were investigated for structural hydroxyl content in nominally anhydrous minerals. Garnet shows pronounced absorption in the wavenumber ranges of 3596–3633, 3651–3694, and 3698–3735 <span class="inline-formula">cm⁻¹</span> and minor absorption centred at about 3560 <span class="inline-formula">cm⁻¹</span>. Clinopyroxene with aligned inclusions of either quartz, albite, or quartz <span class="inline-formula">+</span> pargasite has major absorption at 3450–3471 and 3521–3538 <span class="inline-formula">cm⁻¹</span> and minor absorption centred at 3350 and approximately 3625 <span class="inline-formula">cm⁻¹</span>. The latter band is strongest in a sample with minute lamellar inclusions rich in Al, Fe, and Na and was excluded from hydroxyl quantification. Orthopyroxene has large, narrow absorption peaks centred at 3415 and 3515 <span class="inline-formula">cm⁻¹</span> and smaller peaks at 3555, 3595, and 3625 <span class="inline-formula">cm⁻¹</span>. Five orthopyroxene-bearing eclogites exhibit relatively homogeneous amounts of structural hydroxyl in garnet (13–32 <span class="inline-formula">µg g⁻¹</span>), clinopyroxene (119–174 <span class="inline-formula">µg g⁻¹</span>), and orthopyroxene (4–17 <span class="inline-formula">µg g⁻¹</span>). The outer 200 <span class="inline-formula">µm</span> wide rims of the orthopyroxene grains illustrate a late hydroxyl loss compared to core values of about 30 %, which is not evident in garnet and clinopyroxene. In contrast, the other five orthopyroxene-free eclogites exhibit variable amounts of hydroxyl in garnet (8–306 <span class="inline-formula">µg g⁻¹</span>) and clinopyroxene (58–711 <span class="inline-formula">µg g⁻¹</span>). Apart from extreme values, the structural hydroxyl content of clinopyroxene in the eclogites studied is lower than in comparable ultra-high-pressure metamorphic samples, e.g. both metasomatised and pristine eclogite xenoliths from the lithospheric mantle underneath several cratons and coesite- and quartz-eclogites from the Erzgebirge and the Kokchetav massifs, by up to several hundreds of micrograms per gram (<span class="inline-formula">µg g⁻¹</span>). The low structural hydroxyl contents, the deficiency of molecular water, and the preservation of diffusion-sensitive evidence from the mineral chemistry for metamorphism well beyond the stability field of amphibole suggest that oriented inclusions of quartz <span class="inline-formula">+</span> pargasite were formed isochemically during decompression. In addition, structural hydroxyl content in clinopyroxene is inversely correlated with metamorphic pressure estimates obtained from orthopyroxene of the same samples. Therefore, structural hydroxyl in nominally anhydrous eclogite minerals can serve as an indicator of the effectiveness of retrogression.</p>

Senhu Lin, Lianhua Hou, Xia Luo

Shale is of strong heterogeneity. The mineral composition has a significant influence on the diagenetic evolution, pore network formation, hydrocarbon content, oil mobility, and reservoir stimulation of shale. Accurate mineral analysis of shale is an essential precondition for scientific research and industrial production. In this study, we present a new quantitative method for shale mineral analysis based on high-resolution images, using a combination of QEMSCAN and MAPS technology. We overcome the problem of errors between the morphology and content of certain minerals identified by QEMSCAN technology and the actual results and take full advantage of high-resolution large-scale backscatter scanning electron microscopy (MAPS technology) to process clay-grade mineral image data with complex contact relationships. Specifically, we realize the correction of QEMSCAN mineral quantitative analysis results through image smoothing, image alignment, image segmentation, morphological analysis, and other image processing technologies. The method enables the precise and fast measurement of mineral types, contents, and two-dimensional (2D) distributions. It provides a more credible result consistent with geological reality than QEMSCAN. A straightforward application of the new method is refined mineralogical analysis, including the characterization of pores, fractures, organic matter, and/or mineral grains in geological materials.

H. Y. Hu, R. J. Stern, Y. Rojas‐Agramonte et al.

Abstract The Greater Antilles islands of Cuba, Hispaniola, Puerto Rico and Jamaica plus the Virgin Islands host fragments of the fossil convergent margin that records Cretaceous subduction (operated for about 90 m.y.) of the American plates beneath the Caribbean plate and ensuing arc‐continent collision in Late Cretaceous‐Eocene time. The “soft” collision between the Greater Antilles Arc (GAA) and the Bahamas platform (and the margin of the Maya Block in western Cuba) preserved much of the convergent margin. This fossil geosystem represents an excellent natural laboratory for studying the formation and evolution of an intra‐oceanic convergent margin. We compiled geochronologic (664 ages) and geochemical data (more than 1,500 analyses) for GAA igneous and metamorphic rocks. The data was classified with a simple fourfold subdivision: fore‐arc mélange, fore‐arc ophiolite, magmatic arc, and retro‐arc to inspect the evolution of GAA through its entire lifespan. The onset of subduction recorded by fore‐arc units, together with the oldest magmatic arc sequence shows that the GAA started in Early Cretaceous time and ceased in Paleogene time. The arc was locally affected (retro‐arc region in Hispaniola) by the Caribbean Large Igneous Province (CLIP) in Early Cretaceous and strongly in Late Cretaceous time. Despite multiple biases in the database presented here, this work is intended to help overcome some of the obstacles and motivate systematic study of the GAA. Our results encourage exploration of offshore regions, especially in the east where the forearc is submerged. Offshore explorations are also encouraged in the south, to investigate relations with the CLIP.

علی شیدائی, محمد شریفی

تفسیر داده‌های فشار مخازن شکافدار طبیعی به‌ خصوص در ایران اهمیت ویژه‌ای دارد. مهم‌ترین تئوری برای تفسیر داده‌های فشار مخازن شکافدار، تئوری تخلخل دو‌گانه است که توسط وارن و روت ارایه شد. مطالعات اخیر نشان‌ داده است که این تئوری به دلیل فرضیات محدودکننده‌ای که دارد، برای همه‌ی مخازن شکافدار کاربرد ندارد. در این مطالعه با رویکرد شبیه‌سازی عددی، بدون در نظر گرفتن معادلات تحلیلی و نیمه‌تحلیلی و فرضیات آنها به بررسی رفتار فشارگذرای مخازن شکافدار پرداخته شد. بدین منظور، مجموعه‌‌ای از مدل‌ها شامل شبکه‌شکاف پیوسته و ناپیوسته در نرم‌افزار اکلیپس شبیه‌سازی شد. شکل معروف چاه‌آزمایی وارن و روت در همه شبیه‌سازی‌ها مشاهده شد با این تفاوت که برای حالت چاه حفر شده در ماتریکس مشخص‌ و واضح و برای حالت چاه متقاطع با شکاف قابل صرفنظر کردن بود، زیرا این حالت برای چاه متقاطع با شکاف به سرعت اتفاق افتاده و عملا ثبت چنین رخدادی در واقعیت امکان ندارد.  نتایج شبیه‌سازی برای حالت چاه متقاطع با شکاف، رژیم جریانی خطی دو‌گانه (شیب یک‌چهارم) را نشان داد که مدت زمان این رژیم جریانی با گسسته شدن شبکه‌شکاف افزایش پیدا کرد. این رژیم جریانی در دو حالت به رژیم جریان خطی (شیب یک‌دوم) تبدیل شد: 1- افزایش تراوایی شکاف‌ها در شبکه‌شکاف پیوسته 2- شکاف‌های کوچک ناپیوسته. نتایج آنالیز حساسیت بر روی مکان چاه در حالت چاه حفر شده در ماتریکس نشان داد که با نزدیک شدن چاه به شبکه‌شکاف، زمان ظهور دوره‌گذار کاهش و عمق آن افزایش پیدا می‌کند. همچنین در حالت چاه حفر شده در ماتریکس، کاهش تراوایی شکاف‌ها در شبکه‌شکاف پیوسته و نیز گسسته شدن شبکه‌شکاف موجب کاهش عمق دوره‌گذار شد ولی در زمان ظهور این دوره تاثیری نداشت.

Külköylüoğlu Okan, Yavuzatmaca Mehmet, Yılmaz Ozan et al.

Since its first description from Madagaskar, there are about 16 living (Recent) species of the genus Zonocypris reported from Afrotropical, Neotropical and Palearctic regions. Similarly, there are about 16 fossil with two (sub)species of the genus known from the Early Cretaceous (e.g., India, France, Russia, China, Brazil) to Holocene (e.g., Albania). Among the species, the only species known with fossil and living species is Zonocypris costata. In Turkey, Zonocypris membranae with two subspecies (Z. m. membranae,Z. m. quadricella) is the only fossil species known while living individuals of Z. costata were encountered the southeast Anatolia. Additionally, Zonocypris mardinensis n. sp. is now proposed as a new species which shows clear differences in the soft body parts (e.g., aesthetasc ya in A1, knife-type G2 claw, shapes of clasping organs and hemipenis) and carapace structure (e.g., LV with extension, RV with posterior denticles). Overall, living species reported herein seem to inhabit comparatively warm (15–30 °C) within the ranges of slightly acidic to alkaline (pH 6.81–8.44) and low to well oxygenated waters (3.05–18.8 mg/l) where they can tolerate salinity (electrical conductivity 103–1910 μS/cm) values within a limited elevational range (336–991 m). Our results suggest that geographic distribution of the living species of the genus is limited within southern parts of Turkey while fossil forms seem to exhibit much wider distribution in northern parts. Anatolian Diagonal as physical barrier may be considered to play a critical role on separating fossil (east-north regions) and extant (southeast region) species of the genus in Turkey. This is the first supportive evidence provided by the species of the genus Zonocypris that geographic barrier could have played the main role on its distribution.

S. Philippo, F. Hatert, Y. Bruni et al.

<p>Luxembourgite, ideally <span class="inline-formula">AgCuPbBi₄Se₈</span>, is a new selenide discovered at Bivels, Grand Duchy of Luxembourg. The mineral forms tiny fibres reaching 200&thinsp;<span class="inline-formula">µ</span>m in length and 5&thinsp;<span class="inline-formula">µ</span>m in diameter, which are deposited on dolomite crystals. Luxembourgite is grey, with a metallic lustre and without cleavage planes; its Mohs hardness is 3 and its calculated density is 8.00&thinsp;g&thinsp;cm<span class="inline-formula">⁻³</span>. Electron-microprobe analyses indicate an empirical formula <span class="inline-formula">Ag_1.00(Cu_0.82Ag_0.20Fe_0.01)_Σ1.03Pb_1.13Bi_4.11(Se_7.72S_0.01)_Σ7.73</span>, calculated on the basis of 15 atoms per formula unit. A single-crystal structure refinement was performed to <span class="inline-formula"><i>R</i>₁=0.0476</span>, in the <span class="inline-formula"><i>P</i>2₁∕<i>m</i></span> space group, with <span class="inline-formula"><i>a</i>=13.002(1)</span>, <span class="inline-formula"><i>b</i>=4.1543(3)</span>, <span class="inline-formula"><i>c</i>=15.312(2) <i>Å</i></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">β</mi><mo>=</mo><mn mathvariant="normal">108.92</mn><mo>(</mo><mn mathvariant="normal">1</mn><mo>)</mo><msup><mi/><mo>∘</mo></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="73pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="4d920107eb4a98473050fd7bdaf16dee"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ejm-32-449-2020-ie00001.svg" width="73pt" height="13pt" src="ejm-32-449-2020-ie00001.png"/></svg:svg></span></span>, <span class="inline-formula"><i>V</i>=782.4(2) <i>Å</i>³</span>, <span class="inline-formula"><i>Z</i>=2</span>. The crystal structure is similar to that of litochlebite and watkinsonite and can be described as an alternation of two types of anionic layers: a pseudotetragonal layer four atoms thick and a pseudohexagonal layer that is one atom thick. In the pseudotetragonal layers the Bi1, Bi2 ,Bi3, Pb, and Ag1 atoms are localised, while the Cu2 and Bi4 atoms occur between the pseudotetragonal and the pseudohexagonal layers. Bi1, Bi2, and Bi3 atoms occur in weakly distorted octahedral sites, whereas Bi4 occurs in a distorted 7-coordinated site. Ag1 occupies a fairly regular octahedral site, Cu2 a tetrahedral position, and Pb occurs on a very distorted 8-coordinated site.</p>

محمدصادق موحد, سید حسن طباطبایی, مهیار یوسفی

فلزات سنگین به‌دلیل سمی‌بودن و پایداری در طبیعت، از آلاینده‌های خطرناک محیط زیست هستند. این فلزات می‌توانند با تغییر در خواص شیمیایی رسوبات، فلزات و آلاینده‌ها را به آب روی رسوب خود انتقال دهند و با تحرک دوباره آنها در محیط، به‌عنوان منبع آلودگی عمل کنند. در این خصوص معادن فلزی و فعالیت‌های معدنی یکی از منابع اصلی آلودگی فلزات سنگین در محیط‌های محلی هستند. در مطالعه حاضر به‌منظور ارزیابی سطوح آلودگی فلزات سنگی (Cu، Ni، Cr، Zn، Pb و Mn)  از تحلیل داده‌های ژیوشیمیایی رسوبات آبراهه‌ای ورقه 1:100.000 خوی استفاده شده است. از آنجا‌که داده‌های رسوب آبراهه‌ای، معرف مواد بالادست خود هستند، برای تحلیل بهتر آلودگی از روش حوضه آبریز نمونه (SCB) استفاده و براساس آن، غلظت زمینه محلی ناشی از لیتولوژی به روش میانگین وزن‌دار محاسبه و به‌عنوان زمینه در شاخص‌های کیفیت رسوب مانند شاخص ضریب آلودگی و شاخص خطر زیست‌محیطی استفاده شد. عناصر نیز برای مشارکت در شاخص‌های مرکب کیفیت رسوبات، با روش‌های آماری چند متغیره مانند ماتریس همبستگی پیرسون، آنالیز فاکتوری و خوشه‌بندی سلسله مراتبی مورد بررسی قرار گرفتند. مطالعه حوضه‌های آلوده نشان‎داد که منابع آلودگی بیشتر به‌دلیل خصوصیات زمین‌شناسی منطقه بوده اما در برخی موارد فعالیت‌های معدنی و انسانی در گسترش آلودگی بسیار موثر بوده‌اند. در گام بعدی برای رتبه‌بندی مناطق آلوده، دبی رسوب مربوط به هر حوضه محاسبه و با توجه به سطح آلودگی رسوب، پتانسیل تولید حجمی و دبی رسوب، 127 حوضه آلوده Cr و Ni  به‎روش تاپسیس رتبه‌‌بندی شدند.

Bruno Araujo Furtado de Mendonça, Carlos Ernesto Gonçalves Reynaud Schaefer, Elpídio Inácio Fernandes-Filho et al.

ABSTRACT The northwestern part of the Acre State (Brazil) possesses singular soils in Brazilian Amazonia, but have been very little studied. This study aimed to discuss the genesis and some micropedological aspects of the soils from Serra do Divisor and adjacent floodplain soils of the Moa river, to enhance the knowledge on their formation. A toposequence of soils ranging from the uppermost part of sub-Andean Serra do Divisor to the Alluvial soils of Moa river floodplain was studied, regarding chemical, physical, mineralogical, and micromorphological attributes. The parent material of the Serra do Divisor is basically quartzose sandstone, and the soils along the toposequence were classified as Typic Haplorthods (P1), Spodic Quartzipsamment (P2), Lithic Quartzipsamment (P3), and Lithic Quartzipsamment (P4). Along the Moa river floodplain, we also identified and collected, Typic Udifluvent (P5), Typic Kandiudult (P6), Typic Kandiudalf (P7), and Arenic Plinthic Kandiudult (P8). The Serra do Divisor soils have very low fertility, high acidity, and low cation exchange capacities, presenting a coarse sandy texture, even shallow pedons. The X-ray diffraction analysis of these soils indicates the predominance of kaolinite, with traces of quartz and gibbsite. The shallow mountain Podzols on sandstone have an expressive accumulation of organic material in surface horizons, with evidence of ferrihydrite and imogolite in the subsurface. At the Moa river floodplain, all soils are originated from recent sediments (Cenozoic), which have a geological source upstream. Varying sedimentary layers are key aspects influencing soil genesis. Those soils have evidence of 2:1 clays with hydroxyl-Al interlayers in subsurface horizons. The Serra do Divisor steep landforms and the coarse texture of the soils promote good drainage and favor leaching and chemical impoverishment. Kaolinite and gibbsite were formed by severe leaching and there are evidences of in situ neoformation of gibbsite by extreme Si losses. All studied soils have some peculiarities such as high accumulation of organic material or 2:1 clay minerals. Most investigated soils were affected by colluvial, reworking, mass movements or a strong variation on sedimentation.

Akinfiev Nikolay

All available experimental data on dissociation constants of aqueous hydroxides of Na, K, and Li were critically assembled and together with quantum chemical estimations used to evaluate parameters of the AD EoS [1] for corresponding aqueous molecules NaOH(aq), KOH(aq), and LiOH(aq). Use of the proposed approach allows proper prediction of the whole set of thermodynamic properties of these hydroxides over a wide range of temperatures (0 – 800 °C), pressures (0.1 – 800 MPa) and solvent densities (0.03 – 1.1 g·cm-3).

W. Huang, W. Huang, H. Saathoff et al.

<p>The chemical composition and volatility of organic aerosol (OA) particles were investigated during July–August 2017 and February–March 2018 in the city of Stuttgart, one of the most polluted cities in Germany. Total non-refractory particle mass was measured with a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS; hereafter AMS). Aerosol particles were collected on filters and analyzed in the laboratory with a filter inlet for gases and aerosols coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-HR-ToF-CIMS; hereafter CIMS), yielding the molecular composition of oxygenated OA (OOA) compounds. While the average organic mass loadings are lower in the summer period (<span class="inline-formula">5.1±3.2</span>&thinsp;<span class="inline-formula">µ</span>g&thinsp;m<span class="inline-formula">⁻³</span>) than in the winter period (<span class="inline-formula">8.4±5.6</span>&thinsp;<span class="inline-formula">µ</span>g&thinsp;m<span class="inline-formula">⁻³</span>), we find relatively larger mass contributions of organics measured by AMS in summer (<span class="inline-formula">68.8±13.4</span>&thinsp;%) compared to winter (<span class="inline-formula">34.8±9.5</span>&thinsp;%). CIMS mass spectra show OOA compounds in summer have O&thinsp;:&thinsp;C of <span class="inline-formula">0.82±0.02</span> and are more influenced by biogenic emissions, while OOA compounds in winter have O&thinsp;:&thinsp;C of <span class="inline-formula">0.89±0.06</span> and are more influenced by biomass burning emissions. Volatility parametrization analysis shows that OOA in winter is less volatile with higher contributions of low-volatility organic compounds (LVOCs) and extremely low-volatility organic compounds (ELVOCs). We partially explain this by the higher contributions of compounds with shorter carbon chain lengths and a higher number of oxygen atoms, i.e., higher O&thinsp;:&thinsp;C in winter. Organic compounds desorbing from the particles deposited on the filter samples also exhibit a shift of signal to higher desorption temperatures (i.e., lower apparent volatility) in winter. This is consistent with the relatively higher O&thinsp;:&thinsp;C in winter but may also be related to higher particle viscosity due to the higher contributions of larger-molecular-weight LVOCs and ELVOCs, interactions between different species and/or particles (particle matrix), and/or thermal decomposition of larger molecules. The results suggest that whereas lower temperature in winter may lead to increased partitioning of semi-volatile organic compounds (SVOCs) into the particle phase, this does not result in a higher overall volatility of OOA in winter and that the difference in sources and/or chemistry between the seasons plays a more important role. Our study provides insights into the seasonal variation of the molecular composition and volatility of ambient OA particles and into their potential sources.</p>

Elif AKISKA

Bu çalışmada Sinanpaşa (Afyon) Neojen havzası içerisinde iki bölgede (güneyde Kırka bölgesi, kuzeyde Karacaören bölgesi) yer alan kömür örneklerinin petrografi k ve palinolojik incelemeleri yapılmıştır. Kömür içeren Neojen tortulları beş fasiyese ayrılarak incelenmiştir. Bunlar alttan üste doğru; paleosol, bağlayıcı destekli çakıltaşı, kömürlü çamurtaşı, kumtaşı-kiltaşı ve laminalı çamurtaşı fasiyesleridir. Kömürlü seviyeler belirgin olarak kömürlü çamurtaşı fasiyesi içerisinde yer almaktadır. Ayrıca bağlayıcı destekli çakıltaşı ile kumtaşı-kiltaşı fasiyeslerinde de çeşitli boydaki kömürleşmiş malzemeye rastlanmaktadır. İnceleme alanından derlenen örneklerin kömür petrografi si incelemeleri yapılmış ve bunlara bağlı olarak kömürlerin çökelme ortamları ile ilişkili yorumlamaya gidilmiştir. Buna göre bu kömürlerin başlıca gelinitçe zengin olan hüminit maseral grubunu içerdiği, Rmax değerlerine göre alt bitumlu kömür sınıfl amasına girdiği ve göllerle ilişkili bataklık zonlarında çökeldiği sonucu ortaya çıkmaktadır. Örneklerin derlendiği düzeye ait palinolojik veriler kömürlü birimlerin yaşının Orta Miyosen olduğunu işaret etmektedir. Paleoiklim çalışmaları sonucunda elde edilen MAT, CMT, WMT ve MAP parametrelerine dayanarak çalışma alanındaki iklimsel koşulların mevsimselliğe bağlı olarak değiştiği gözlenmiştir. Sonuç olarak, kömürlü seviyelerin oluştuğu dönemde ılıman iklim koşullarının varlığından söz edilebilir.

Ramazan DEMİRCİOĞLU, Yaşar EREN

Çamardı (Niğde) yöresinde, Niğde Masifi mermer, gnays, kuvarsit ve amfibolitlerden oluşmuştur. Masife ait bu kayaçlar Kretase yaşlı granodiyoritler tarafından kesilmiştir. Paleosen-Eosen düşük dereceli başkalaşım kayaçları masifin otokton örtüsünü oluşturur. Bu birimler, Üst Kretase-Paleosen yaşlı flişoyid ve ada yayı özelliğindeki kayaçlar tarafından tektonik olarak üstlenir. Yörenin en genç birimlerini ise Oligosen-Kuvaterner yaşlı karasal ve volkanik kayaçlar oluşturur. Niğde masifi metamorfitleri en az dört evreli (D1, D2, D3ve D4) sünek deformasyona ve kıvrımlanmaya uğramıştır. D1 evre deformasyonla, masifin kayaçları yatık-izoklinal olarak kıvrımlanmış (F1-F2 evre kıvrımlanma) ve eksen düzlemlerine paralel foliasyonlu (S1) bir yapı kazanmıştır. Kayaçların tabaka (So) düzlemlerinin izoklinal ve şiddetli kıvrımlanmasınedeniyle tabaka transpozisyonu gelişmiş ve yalınmış kıvrım yapıları oluşmuştur. D2 evre deformasyonla, harita ölçeğinde kuzeydoğu-güneybatı yönelimli ve hem kuzeydoğuya, hem de güneybatıya dalımlı kıvrımlar (F3 evrekıvrımlanma) gelişmiştir. F1-F2 ve F3 evre kıvrımların girişimi sonucu yörede Tip-2 türü (mantar kıvrımı) kıvrımlanmış kıvrımlar oluşmuştur. İkinci evre mesoskopik kıvrımlar sıkışık-izoklinal geometrili olup, asimetrik ve eğik kıvrım özelliği sunarlar. İnceleme alanında D3 evre kıvrımlanma sonucu bölgede büyük bir dom yapısı gelişmiştir. D4 evre kıvrımlar ise harita ölçeğinde D2 evreye yaklaşık dik yönelimli ve kuzeybatı-güneydoğu gidişli ve güneydoğuya dalımlı sinform ve antiform yapıları oluşturmuştur. D4 evre deformasyonla temel ve örtü kayaçları ile birlikte deforme olmuştur (F5-evre). Mikroskopik analizler, Kretase-Eosen yaşlı kayaçların, bu evre deformasyonla düşük dereceli yeşilşist fasiyesinde başkalaşıma uğradığını göstermektedir F5 evre kıvrımların geometrisi, temel ve örtü kayaçlarının beraberce deforme olduğu yörelere özgü kıvrım şeklini (kasp–lob yapısı) yansıtmaktadır.

Ilver M. Soto-Loaiza, José Quintín Cuador-Gil

The objective of the investigation was to identify the geological factors affecting the spatial continuity of the flow during the process of flank water injection in the units operating in the Lower Lagunilla Hydrocarbon Ore Body. This included the evaluation of the recovery factor, the petro-physic properties such as porosity, permeability, water saturation and rock type and quality in each flow unit. it was observed that the rock type of the geologic structure in the ore body is variable. The lowest values for the petro-physic properties were found in the southern area while a high variability of these parameters was observed in the northern and central areas. It was concluded that the northern area has a great potential for the development of new injection projects for petroleum recovery.

Kalle KIRSIMÄE

James Dwight Dana, C. Hurlbut

K. Venkatarathnam, P. Biscaye

N. M. Shukri