Mineralogy and Petrology最新文献

{"title":"High-grade metamorphism of banded iron formations: the role of saline fluids in promoting the growth of pyroxene and garnet reaction textures along magnetite-quartz grain boundaries","authors":"Paul M. George,&nbsp;Daniel E. Harlov,&nbsp;Brian F. Windley,&nbsp;Madhusoodhan Satish-Kumar,&nbsp;Krishnan Sajeev,&nbsp;Ming-Guo Zhai","doi":"10.1007/s00710-024-00854-5","DOIUrl":"10.1007/s00710-024-00854-5","url":null,"abstract":"<div><p>Metamorphosed banded iron formation (BIF) in granulite-amphibolite facies, tonalitic orthogneisses from a series of locations in the Kolli Massif of southern India are described and analysed with regard to their lithologies, whole rock chemistry, mineral reaction textures, and mineral chemistry. On the basis of their mineral reaction textures along magnetite-quartz grain boundaries these BIFs are grouped according to their predominant silicate mineralogy: 1) amphibole; 2) orthopyroxene; 3) orthopyroxene–clinopyroxene; 4) orthopyroxene-clinopyroxene-garnet; 5) clinopyroxene-garnet-plagioclase; and 6) Fe-Mg silicates are absent. Two-pyroxene and garnet-pyroxene Fe-Mg exchange thermometry, coupled with thermodynamic pseudo-section modelling of whole rock data from one of the magnetite-quartz-orthopyroxene-clinopyroxene-bearing lithologies, indicates that the magnetite-quartz-orthopyroxene-clinopyroxene-garnet assemblages formed at ~900 to 1200 MPa and 750 to 900 °C under relatively low H₂O activities. Magnetite-quartz-orthopyroxene reaction textures were experimentally replicated at 800 and 900 °C and 1000 MPa in a synthetic BIF using isolated magnetite grains in a quartz matrix to which was added a hypersaline Mg- and Al-bearing fluid (approximately 1% by mass), which permeated along all the grain boundaries. The fact that Fe-Mg silicate reaction textures did not form in one of the BIF samples, which had experienced the same <i>P-T</i> conditions as the other BIF samples, suggests that, unless a BIF initially incorporated Mg, Al, and Ca during formation with or was infiltrated from the surrounding rocks by Mg-, Al-, and Ca-bearing saline fluids, these silicate minerals could not and would not have formed from the inherent magnetite and quartz during granulite-facies and amphibolite-facies metamorphism.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 2","pages":"185 - 208"},"PeriodicalIF":1.4,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00710-024-00854-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140634369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical characterization and zircon U–Pb geochronology of the Tirodi Gneissic Complex, Central Indian Tectonic Zone (CITZ): constraints on petrogenesis, Proterozoic crustal evolution and tectonic setting","authors":"Mukesh K. Mishra,&nbsp;Meraj Alam,&nbsp;Tatiana V. Kaulina,&nbsp;Talat Ahmad","doi":"10.1007/s00710-024-00853-6","DOIUrl":"10.1007/s00710-024-00853-6","url":null,"abstract":"<div><p>The Tirodi Gneissic Complex (TGC) represents the basement sequence of the Central Indian Tectonic Zone (CITZ), underlying the Proterozoic supracrustal sequences of the Sausar and Betul Groups of rocks. Lithologically, the TGC constitutes a combination of pink and grey granitic gneiss assemblages, characterised by biotite-rich, hornblende-biotite-rich, and muscovite-biotite-rich granite gneiss. Compositionally, the TGC granitoids represent tonalite-trondhjemite-granodiorite to granite, and have calc-alkaline lineage with metaluminous to peraluminous characteristics. Geochemically, they dominantly belong to A2-type granitoids. Chondrite normalised REE ratios of La/Sm, La/Yb, La/Gd, and Gd/Yb indicate diverse LREE/HREE enrichment. Multi-element patterns for the TGC granitoids are characterised by light rare earth elements (LREE) and large ion lithophile elements (LILE) enrichment and depletion of high field strength elements (HFSE: Nb, P, and Ti) and strong positive Pb and Th anomalies. The observed negative anomalies for HFSE are attributed to diverse crustal/lithospheric sources, with some influence from K-feldspar, plagioclase and Ti-oxide fractionation. Sm–Nd data presents initial ¹⁴³Nd/¹⁴⁴Nd (t = 1.7 Ga) ratios (0.509898 to 0.510508), and ε_Nd (t = 1.7 Ga) is (+ 0.58 to -10.59), with T_DM model ages ranging from 2.11 to 2.95 Ga. Such a wide range of ε_Nd (t = 1.7 Ga), indicates heterogeneous crustal/lithosphere sources, which have probably experienced longer crustal residence times. Zircon U–Pb ages for individual TGC samples are 1506 ± 11 Ma (TG-01), 1534 ± 26 Ma (MU-5), 1675 ± 9 Ma (BT-4), 1724 ± 11 Ma (BT-3), 1730 ± 13 Ma (BT-4), and 1960 ± 2 Ga (Ms-2), respectively. These ages have probably recorded the key periods of the Columbia supercontinent's assembly, growth, and breakup. Geochemical and geochronological results suggest that the TGC granitoids have a crustal/lithospheric origin and are formed by partial melting of felsic sources in dominantly VAG (volcanic arc granite) and, to some extents, WPG (within-plate granite) settings.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 2","pages":"159 - 183"},"PeriodicalIF":1.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140568545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduced mineral assemblages of superficial origin in west-central Jordan","authors":"Oleg S. Vereshchagin,&nbsp;Maya O. Khmelnitskaya,&nbsp;Mikhail N. Murashko,&nbsp;Yevgeny Vapnik,&nbsp;Anatoly N. Zaitsev,&nbsp;Natalia S. Vlasenko,&nbsp;Vladimir V. Shilovskikh,&nbsp;Sergey N. Britvin","doi":"10.1007/s00710-024-00851-8","DOIUrl":"10.1007/s00710-024-00851-8","url":null,"abstract":"<div><p>Mineral assemblages formed at low oxygen fugacity are commonly confined to the lithologies of extraterrestrial or deep Earth origin. The occurrences of reduced mineral phases in upper crustal rocks [formed under oxygen fugacity conditions below the iron-wüstite (IW) buffer] are rare. However, they are important for understanding the chemical drivers of natural redox processes. Here, we present detailed studies of reduced mineral assemblages, which were found in situ in superficial combustion metamorphic (CM) rocks of west-central Jordan and compare them to reduced mineral assemblages found in situ in the CM rocks of south-central Israel. The studied assemblages contain a suite of exotic phases more typical of meteorites: native iron, phosphides (schreibersite, Fe₃P; allabogdanite, Fe₂P; transjordanite, Ni₂P; murashkoite, FeP; halamishite, Ni₅P₄; zuktamrurite, FeP₂; polekhovskyite, MoNiP₂), and sulphides (daubréelite, FeCr₂S₄; oldhamite, CaS; troilite, FeS), part of which (native iron, allabogdanite, halamishite, polekhovskyite, daubréelite) have not previously been discovered in the CM rocks of west-central Jordan. The mineralogical diversity of terrestrial phosphides and the occurrence of Ni- / Mo-rich phases can be explained by (1) high P, Ni, and Mo content in the sedimentary protolith, (2) transformations of primary Fe₃P / Fe₂P, (3) extreme disequilibrium of the processes, and (4) crystal-chemical control of Ni- / Mo- speciation.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 2","pages":"305 - 319"},"PeriodicalIF":1.4,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140200356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry of tourmaline-rich rocks in the Gavião Block, Northern São Francisco craton: implications for its formation","authors":"Eliana Marinho Branches Farias,&nbsp;Stefano Albino Zincone,&nbsp;Cláudia dos Santos,&nbsp;Gláucia Nascimento Queiroga,&nbsp;Flávia Braga de Oliveira,&nbsp;Gilberto Henrique Tavares Álvares da Silva,&nbsp;Leonardo Martins Graça","doi":"10.1007/s00710-024-00852-7","DOIUrl":"10.1007/s00710-024-00852-7","url":null,"abstract":"<div><p>Tourmaline is a valuable forensic mineral that contains a wide range of elemental components capable of reconstructing its geologic evolution. In this study, we developed detailed petrographic and geochemical research on tourmaline-bearing rocks and tourmalinites found surrounding the ca. 3.30 Ga rhyolite of the Gavião Block, northern São Francisco Craton. Two distinct types of mineral assemblages in the tourmaline-bearing rocks are recognized based on the presence of sulfides, oxide minerals, and carbonaceous matter. Along with these tourmaline-bearing rocks, tourmalinite samples are found. The mineral chemistry of tourmalines from the two types of tourmaline-bearing rocks reveals mainly schorl-dravite as tourmaline from a mineral assemblage containing quartz, tourmaline, pyrite, and hematite, and a diverse composition ranging from schorl-dravite, feruvite-uvite, and schorl-feruvite solid solutions for tourmalines present in the mineral assemblage that contains quartz, pyrite, and carbonaceous matter. The tourmaline composition is essentially foitite-schorl in tourmalinite samples. Most of the metasedimentary rocks studied have felsic and mafic source compositions. The interaction of hydrothermal fluid was crucial for the formation of sulfide and tourmaline minerals. However, distinct tourmaline origins are recognized in tourmaline-rich rocks, pointing out the relevance of sedimentary and metamorphic processes.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 2","pages":"141 - 158"},"PeriodicalIF":1.4,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140156200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diamond sources of the Juína region, Amazonian craton: textural and mineral chemical characteristics of Kimberley-type pyroclastic kimberlites","authors":"Izaac Cabral-Neto,&nbsp;Excelso Ruberti,&nbsp;David Graham Pearson,&nbsp;Yan Luo,&nbsp;Rogério G. Azzone,&nbsp;Francisco V. Silveira,&nbsp;Vidyã V. Almeida","doi":"10.1007/s00710-023-00849-8","DOIUrl":"10.1007/s00710-023-00849-8","url":null,"abstract":"<div><p>Juína is the second-largest diamond-producing municipality in Brazil and is globally known for its outstanding sublithospheric diamond occurrences in both placer and kimberlite-hosted deposits. However, the scarcity of petrological data for Juína kimberlite pipes hampers understanding the nature and mantle source of these primary diamond sources in this region. Here, we present a textural and mineralogical study of ten kimberlite pipes from the Juína area. Based on petrographic features and mineral compositions, we interpret the studied Juína pipes as archetypal kimberlites with pyroclastic emplacement styles filled with resedimented volcaniclastic kimberlite and Kimberley-type pyroclastic kimberlite variants. The composition and texture of the magmatic phases, particularly spinel and phlogopite, suggest crystallisation from kimberlite sensu stricto magmas. The presence of high-Na eclogitic garnets and the absence of high-Cr low-Ca G10 garnets within the mantle xenocryst suite suggest the likelihood of eclogitic diamonds among Juína's lithospheric diamond populations. The Zr and Y contents, Ti/Eu and Zr/Hf ratios in the peridotite garnets, and Zr contents, Ca/Al, La_N/Yb_N (primitive-mantle normalised), Ti/Eu, and Zr/Hf ratios in the clinopyroxenes suggest a solid connection to kimberlite melt-related mantle metasomatism. Thermobarometry calculations indicate a relatively narrow stability window (825–936 ºC and 32–36 kbar) for lithospheric diamonds in the Juína region. Our findings have important implications for regional diamond exploration programs, shedding light on the primary sources of Juína's diamonds and contributing to understanding the deep geological processes in the underlying lithospheric mantle beneath the Amazonian craton.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 1","pages":"1 - 22"},"PeriodicalIF":1.4,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138943910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"\"I've Spent My Whole Life Striving to Be Normal\": Internalized Stigma and Perceived Impact of Diagnosis in Autistic Adults.","authors":"Yunhe Huang, Julian N Trollor, Kitty-Rose Foley, Samuel R C Arnold","doi":"10.1089/aut.2022.0066","DOIUrl":"10.1089/aut.2022.0066","url":null,"abstract":"<p><strong>Background: </strong>Receiving an autism diagnosis in adulthood often leads to improved self-understanding and deeper self-reflection, which can have major impacts on people's well-being and sense of identity. However, autism diagnosis also exposes individuals to societal stigma, which may become internalized over time. This study aimed to explore relationships between psychological and service-related impacts of diagnosis and internalized stigma using mixed methods.</p><p><strong>Methods: </strong>One hundred forty-three autistic adults completed an online survey involving impact of diagnosis domains of Self-Understanding, Well-being, Clinician Support, and Service Access, internalized stigma, and open-ended questions on beliefs about autism diagnosis.</p><p><strong>Results: </strong>On average, participants reported mild levels of internalized stigma and positive impact of diagnosis in all domains except Service Access. Older age at diagnosis was positively associated with Clinician Support only. The path analysis model showed positive relationships between impact of diagnosis domains, with Self-Understanding having a positive effect on Well-being via lowered internalized stigma. We developed four themes of <i>Continuity and Acceptance</i>, <i>Late Diagnosis as Regret and Freedom</i>, <i>Coming to Terms with Being Autistic</i>, and <i>Stigma Resistance</i> from qualitative data.</p><p><strong>Conclusions: </strong>Self-understanding protects against the development of internalized autism stigma. Diagnosticians and service providers play an important role in improving self-understanding and well-being in autistic adults. More research is needed to understand the role of age at diagnosis and mechanisms behind positive identity development after autism diagnosis.</p>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"23 4","pages":"423-436"},"PeriodicalIF":1.4,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10726184/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41301477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The auriferous quartz lode of the Veloso deposit, Quadrilátero Ferrífero of Minas Gerais, Brazil: geological characterisation and constraints from tourmaline boron isotopes","authors":"Júlia S. Pimenta,&nbsp;Alexandre R. Cabral,&nbsp;Glaucia Queiroga,&nbsp;Cristiano Lana,&nbsp;Miguel Tupinambá,&nbsp;Armin Zeh,&nbsp;Rogerio Kwitko-Ribeiro","doi":"10.1007/s00710-023-00848-9","DOIUrl":"10.1007/s00710-023-00848-9","url":null,"abstract":"<div><p>Veloso is one of numerous and poorly documented auriferous deposits of Ouro Preto, the town that symbolises the gold rush in Brazil at the turn of the seventeenth century. We present the results of underground geological mapping, combined with a boron (B) isotopic study of tourmaline, an elusive mineral in the auriferous quartz lode of the historical Veloso deposit. Its lode is characteristically brecciated in a host rock that shows no cataclastic fabric. The host rock is itabirite, a metamorphosed banded iron formation. Tourmaline is essentially dravite and locally occurs as abundant crystals in breccia-cementing pockets of goethite, formed from the oxidation of sulfide minerals. Gold is spatially associated with tourmaline in the goethite-rich pockets. In situ measurements for B isotopes yielded δ¹¹B values in the range of −21 to −9‰. This range is similar to that reported for tourmaline of the Passagem de Mariana deposit, the best documented auriferous lode deposit at the south-eastern edge of the Quadrilátero Ferrífero. The tourmaline B isotopic data reflect auriferous fluids of crustal origin that sourced B from metasedimentary rocks, which may include a non-marine evaporitic component.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 1","pages":"89 - 103"},"PeriodicalIF":1.4,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138494547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal chemistry and origin of epidote-(Sr) in alkaline rocks of the teschenite association (Silesian Unit, Outer Western Carpathians, Czech Republic)","authors":"Kamil Kropáč,&nbsp;Zdeněk Dolníček,&nbsp;Pavel Uher,&nbsp;David Buriánek,&nbsp;Tomáš Urubek","doi":"10.1007/s00710-023-00847-w","DOIUrl":"10.1007/s00710-023-00847-w","url":null,"abstract":"<div><p>A new occurrence of epidote-(Sr) CaSr(Al₂Fe³⁺)[Si₂O₇][SiO₄]O(OH), Sr-REE-rich epidote and Sr-rich allanite-(Ce) is located in Lower Cretaceous, Sr-rich hydrothermally altered leucocratic dykes penetrating alkaline igneous rocks (teschenites) near the Nový Jičín town (the Silesian Unit, Outer Western Carpathians). The dykes contain phenocrysts of pyroxene, amphibole, biotite, fluorapatite and dominant felsic groundmass consisting mostly of alkali feldspars and zeolites (analcime, natrolite and thomsonite-Ca). Accessory minerals include Ti-rich magnetite, prehnite, chamosite, pyrite, calcite, (OH, F)-rich grossular, epidote-group minerals, HFSE-, REE-rich minerals, Sr-rich baryte and slawsonite. The Sr-rich epidote forms columnar crystals or irregular aggregates, which are mostly spatially related to chamosite-titanite pseudomorphs; it contains 0.15–0.81 apfu Sr, ≤ 0.55 apfu REE; Fe³⁺/(Fe³⁺ + Al) = 0.16–0.48. The Sr²⁺ substitutes Ca²⁺ in the <i>A2</i> site by a coupled substitution involving other <i>A2</i> (REE³⁺, Th⁴⁺) or <i>M</i> (Al³⁺, Fe³⁺, Fe²⁺) cations. The Sr-rich epidote crystallized from hydrothermal solutions, probably at temperatures between ~ 250–430 °C, during cooling of the host rock. The dykes show higher Sr contents (5680–7830 ppm) and ⁸⁷Sr/⁸⁶Sr_i(120 Ma) ratios (~ 0.7046–0.7047) compared to host mesocratic teschenites (1310–1470 ppm Sr and ~ 0.7038–0.7045, respectively). The Sr isotopes indicate origin of most Sr from primary magmatic plagioclase in parent teschenite. Nevertheless, there also participated external fluids, derived from the Lower Cretaceous seawater or diagenetic waters related to associated siliciclastic sediments with ⁸⁷Sr/⁸⁶Sr_i(120 Ma) = ~ 0.7073–0.7083. These more radiogenic sources contributed at least 6–21% of the bulk Sr budget of the studied Sr-rich epidote-bearing leucocratic dykes.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"118 1","pages":"55 - 70"},"PeriodicalIF":1.4,"publicationDate":"2023-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136281898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Reply to the comment by S. Bouhlel","authors":"Nejib Jemmali,&nbsp;Larbi Rddad,&nbsp;Marta Sośnicka,&nbsp;Emna Rahali,&nbsp;Fouad Souissi,&nbsp;Emmanuel John Carranza","doi":"10.1007/s00710-023-00846-x","DOIUrl":"10.1007/s00710-023-00846-x","url":null,"abstract":"","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"117 4","pages":"801 - 801"},"PeriodicalIF":1.4,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134911865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mallestigite, Pb3Sb(SO4)(AsO4)(OH)6·3H2O, from the type locality – new data, crystal structure, and structural relationships","authors":"Kurt Mereiter,&nbsp;Franz Walter,&nbsp;Hans-Peter Bojar","doi":"10.1007/s00710-023-00837-y","DOIUrl":"10.1007/s00710-023-00837-y","url":null,"abstract":"<div><p>A report of the supergene mineral mallestigite, Pb₃Sb⁵⁺(SO₄)(AsO₄)(OH)₆·3H₂O, from the type locality Neufinkenstein-Grabanz district, Mallestiger Mittagskogel, Carinthia, Austria, is given in order to close gaps that have been left open since its first description. At the type locality, the dump of an abandoned small copper-lead-zinc mine, the mineral occurs frequently in up to ⁓2 mm long clear colourless idiomorphic hexagonal prisms {100} terminated by the bipyramid {101}. Details of the occurrence, paragenesis, physical properties, a FTIR spectrum and X-ray powder diffraction data are reported. Chemical analysis in a scanning electron microscope in conjunction with a crystal structure analysis gave the empirical formula Pb_3.02Sb_1.06(SO₄)_0.96(AsO₄)_0.97(OH)₆·3H₂O. An ab-initio crystal structure determination with CCD diffractometer data, Mo<i>K</i>α radiation, and a nearly untwinned crystal proved that mallestigite is hexagonal, space group <i>P</i>6₃, <i>a</i> = 8.9326(4), <i>c</i> = 11.1044(5) Å, <i>V</i> = 767.33(8) ų, <i>Z</i> = 2, and gave a final <i>R</i>1 = 0.0184 for 1632 independent reflections with <i>I</i> &gt; 2σ(<i>I</i>). Mallestigite belongs to the fleischerite group. The structure is built up from [Sb⁵⁺(OH)₆]^1– octahedra which are linked by triplets of edge-sharing Pb²⁺ into chains [Pb₃Sb(OH)₆]⁵⁺ extending along a 6₃ axis. Each three of such chains are bridged by triplets of H₂O and by rows of SO₄^2– and AsO₄^3– tetrahedra alternating along a 3-fold axis and showing very different links to the Pb atom. Pb²⁺ is in a strongly distorted one-sided [9]-coordination by O atoms that makes the structure clearly hemimorphic. Structural relationships to the fleischerite group minerals schaurteite, genplesite, despujolsite and fleischerite as well as to synthetic Ba₃Sn⁴⁺(SeO₄)₂(OH)₆·3H₂O are outlined and changes in the space group symmetry of despujolsite (<i>P</i><span>(overline6)</span>2c → <i>P</i>6₃/<i>mmc</i>) and fleischerite (<i>P</i><span>(overline6)</span>2c → <i>P</i>6₃) are proposed.</p></div>","PeriodicalId":18547,"journal":{"name":"Mineralogy and Petrology","volume":"117 4","pages":"761 - 774"},"PeriodicalIF":1.4,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00710-023-00837-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135980599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}