Mineralogical Magazine最新文献_第8页

Ferric iron in chrome-bearing spinels: implications for microprobe correction procedures 含铬尖晶石中的铁:微探针校正程序的意义

3区地球科学

Mineralogical Magazine Pub Date : 2023-09-12 DOI: 10.1180/mgm.2023.68

Hugh Rollinson, Jacob Adetunji

{"title":"Ferric iron in chrome-bearing spinels: implications for microprobe correction procedures","authors":"Hugh Rollinson, Jacob Adetunji","doi":"10.1180/mgm.2023.68","DOIUrl":"https://doi.org/10.1180/mgm.2023.68","url":null,"abstract":"Abstract We investigated the compositions of a suite of 361 chrome-bearing spinels from spinel peridotites, ophiolitic mantle chromitites and from layered igneous intrusions in which the Fe 2+ /Fe 3+ ratio has been determined by Mössbauer spectroscopy. We explore the crystal-chemical controls on the distribution of Fe 3+ and on mineral stoichiometry with regard to electron-probe correction procedures for estimating Fe 3+ in spinel. We find that chrome-bearing spinels can be subdivided into three groups: a Cr–Al-rich group; a high-Fe group; and a highly oxidised group. Spinels of the Cr–Al group are found in spinel peridotites and ophiolitic mantle chromitites. They are normal spinels with a low Fe 3+ content and compositions that are close to stoichiometric. Spinels in the high-Fe group are found in layered igneous intrusions. They are also normal spinels which have higher concentrations of Fe 3+ on the octahedrally coordinated site than is found for the Cr–Al group. Stoichiometric calculations tend to overestimate the Fe 3+ content and their compositions do not conform to the MgO–cr# correlation found in the Cr–Al group. Spinels in the highly oxidised group are found in layered intrusions and ophiolitic mantle chromitites. They have (Fe 3+ /ΣFe) Möss > 0.4 and high Cr (cr# > 0.5), but relatively low Fe 2+ (fe# 0.24–0.56). Stoichiometric calculations tend to underestimate the Fe 3+ content. They represent normal spinels in which tetrahedrally coordinated Fe 2+ has been oxidised to Fe 3+ . Our data show that spinels with greater Cr and Fe are sufficiently different in their crystal chemistry from the aluminous spinels to indicate that the EPMA correction procedures developed for Fe 3+ in aluminous spinels on the basis of the Cr/Al ratio, and used in oxy-thermobarometry, are inappropriate for Cr-rich and Fe-rich compositions.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135878432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The trace element chemistry of amphibole, magnetite, and ilmenite as potential exploration guides to metamorphosed Proterozoic Cu-Zn±Pb±Au±Ag volcanogenic massive sulfide deposits in Colorado 美国科罗拉多州角闪洞、磁铁矿、钛铁矿微量元素化学特征对变质元古代Cu-Zn±Pb±Au±Ag火山块状硫化物矿床具有潜在的找矿指导意义

3区地球科学

Mineralogical Magazine Pub Date : 2023-09-11 DOI: 10.1180/mgm.2023.69

Paul G. Spry, Edward H. Berke, Dan Layton-Matthews, Alexandre Voinot, Adriana Heimann, Graham S. Teale, Anette von der Handt

引用次数: 0

Deynekoite, Ca₉ Fe³⁺(PO₄)₇ – a new mineral of the merrillite group from phosphide-bearing contact facies of paralava, Hatrurim Complex, Daba-Siwaqa, Jordan Deynekoite, Ca9 Fe3+(PO4)7——约旦Daba-Siwaqa地区Hatrurim杂岩含磷化接触相副滑石组新矿物

3区地球科学

Mineralogical Magazine Pub Date : 2023-09-11 DOI: 10.1180/mgm.2023.71

Evgeny V. Galuskin, Marcin Stachowicz, Irina O. Galuskina, Krzysztof Woźniak, Yevgeny Vapnik, Mikhail N. Murashko, Grzegorz Zieliński

引用次数: 1

Minasgeraisite-(Y) discredited as an ordered intermediate between datolite and hingganite-(Y) minasgeraite -(Y)是一种介于绿沸石和绿沸石-(Y)之间的有序中间体。

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-09-01 DOI: 10.1180/mgm.2023.67

Daniel Atencio

引用次数: 0

Structure and thermal expansion of end-member olivines I: Crystal and magnetic structure, thermal expansion, and spontaneous magnetostriction of synthetic fayalite, Fe2SiO4, determined by high-resolution neutron powder diffraction 端元橄榄石的结构和热膨胀I：高分辨率中子粉末衍射法测定合成辉绿岩Fe2SiO4的晶体和磁性结构、热膨胀和自发磁致伸缩

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-08-25 DOI: 10.1180/mgm.2023.66

E. Tripoliti, D. Dobson, A. Fortes, A. R. Thomson, P. Schofield, I. Wood

引用次数: 0

Crystal chemistry of zemannite-type structures: IV. Wortupaite, the first new tellurium oxysalt mineral described from an Australian locality 钙镁石型结构的晶体化学：IV.Wortupaite，澳大利亚第一种新的碲氧盐矿物

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-08-24 DOI: 10.1180/mgm.2023.64

Owen P. Missen, Stuart Mills, J. Brugger, W. Birch, P. Elliott

引用次数: 0

Mangani-eckermannite, NaNa2(Mg4Mn3+)Si8O22(OH)2, a new amphibole from Tanohata Mine, Iwate Prefecture, Japan 日本岩手县大和田矿的一种新角闪石——Mangani-eckermannite，NaNa2（Mg4Mn3+）Si8O22（OH）2

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-08-10 DOI: 10.1180/mgm.2023.63

A. Kasatkin, N. Zubkova, A. Agakhanov, N. Chukanov, R. Škoda, F. Nestola, D. I. Belakovskiy, I. Pekov

引用次数: 0

Magmatic and post-magmatic evolution of the Newania carbonatite complex, Rajasthan, north-western India 印度西北部拉贾斯坦邦Newania碳酸岩杂岩的岩浆和岩浆后演化

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-08-08 DOI: 10.1180/mgm.2023.61

Amritpaul Singh, R. Mitchell, Gurmeet Kaur, D. Sarma

{"title":"Magmatic and post-magmatic evolution of the Newania carbonatite complex, Rajasthan, north-western India","authors":"Amritpaul Singh, R. Mitchell, Gurmeet Kaur, D. Sarma","doi":"10.1180/mgm.2023.61","DOIUrl":"https://doi.org/10.1180/mgm.2023.61","url":null,"abstract":"Abstract This work describes the mineralogy of dolomite carbonatite occurring at the Newania carbonatite complex, Rajasthan, north-western India. The mineralogy records the textural and compositional features of magmatic and post-magmatic stages of carbonatite evolution. Ferroan dolomite is the principal constituent and displays variable degrees of deformation, ranging from brittle-to-ductile deformation regimes. Apatite exhibits textural and compositional evolutionary trends from early-to-late stages of carbonatite evolution. Two varieties of amphibole are reported for the first time from this complex, ferri-winchite and cummingtonite; the former is magmatic and the latter is metamorphic in origin. The columbite–tantalite-series minerals are columbite-(Fe), and their paragenesis evolves from composite grains with pyrochlore to individual crystals. Pyrochlore is magmatic with U–Ta–Ti-rich compositions and shows evolution from calciopyrochlore to kenopyrochlore, followed by alteration during late-stages of carbonatite evolution. Monazite and baryte constitute the post-magmatic mineral assemblage; the former is hydrothermal and crystallised after precursor apatite, whereas the latter is associated exclusively with columbite–pyrochlore composites. On the basis of the mineralogy of the carbonatite, it is concluded that the parent magma was generated by low-degree partial melting of magnesite–phlogopite-bearing peridotite.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48666879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Physical properties and crystal structure of near end-member oxy-dravite from the Beluga occurrence, Nunavut territory, Canada 加拿大Nunavut地区Beluga产状近端元氧生辉石的物理性质和晶体结构

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-08-07 DOI: 10.1180/mgm.2023.59

Lenka Skřápková, J. Cempírek, P. Belley, L. Groat, R. Škoda

{"title":"Physical properties and crystal structure of near end-member oxy-dravite from the Beluga occurrence, Nunavut territory, Canada","authors":"Lenka Skřápková, J. Cempírek, P. Belley, L. Groat, R. Škoda","doi":"10.1180/mgm.2023.59","DOIUrl":"https://doi.org/10.1180/mgm.2023.59","url":null,"abstract":"Abstract Oxy-dravite, ideally Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3(O), was found in a composition near its ideal end-member at the Beluga occurrence, Nunavut territory, Canada. It occurs in retrograde albite–muscovite–corundum–calcite domains in a calc-silicate rock. This uncommon oxy-dravite occurs as dark brown, equant to short-prismatic, idiomorphic crystals with vitreous lustre and up to ca. 4 × 3 cm in size. The oxy-dravite is optically uniaxial (–), with ω = 1.6453(5) and ɛ = 1.6074(18); its calculated density is 3.069 g.cm–3 with a compatibility index of 0.016. The Beluga oxy-dravite has trigonal symmetry, space group R3m with a = 15.9121(2) Å, c = 7.1788(10) Å, V = 1574.12(5) Å3 and Z = 3. The crystal structure was refined to R1 = 1.45 using 1613 unique reflections. The empirical crystal-chemical formula is X(Na0.88Ca0.08□0.03K0.01)Y(Al1.49Mg1.31Fe0.15Ti0.04Zn0.01)Z(Al5.42Mg0.58)T(Si5.84Al0.16O18)B(BO3)3V(OH2.95O0.05)W(O0.84OH0.01F0.15). Oxy-dravite in nature commonly occurs in a solid solution with foitite, schorl and oxy-schorl. At the Beluga occurrence, its minor contents of Al, vacancy [□], and Ca are most likely compensated by (□Al)(NaR2+)–1 and (CaMg)(NaAl)–1 exchanges of the oxy-magnesio-foitite and magnesio-lucchesiite components. The Beluga occurrence of oxy-dravite is characterised by an Mg-rich environment related to a metamorphic overprint of the original sedimentary sequence. This sequence of marine dolomitic argillaceous marl was influenced by (B,Cl)-rich fluids, probably proximally-derived from mineral breakdown reactions in the calc-silicate during the retrograde stage of metamorphism. The locality is a rare example of a tourmaline + corundum assemblage.","PeriodicalId":18618,"journal":{"name":"Mineralogical Magazine","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48878509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ferriandrosite-(Ce), a new member of the epidote supergroup from Betliar, Slovakia 铁雄石-(Ce)，绿绿石超群的新成员，产自斯洛伐克的Betliar

IF 2.7 3区地球科学

Mineralogical Magazine Pub Date : 2023-08-07 DOI: 10.1180/mgm.2023.62

M. Števko, Pavol Myšľan, C. Biagioni, D. Mauro, T. Mikuš

引用次数: 0