Krisztián Szentpéteri, K. Cutts, S. Glorie, Hugh O'Brien, Sari Lukkari, Michallik M. Radoslaw, Alan Butcher
Abstract. The in situ Lu–Hf geochronology of garnet, apatite, fluorite, and carbonate minerals is a fast-developing novel analytical method. It provides an alternative technique for age dating of accessory minerals in lithium–caesium–tantalum (LCT) rare-element (RE) pegmatites where zircon is often metamict due to alteration or radiation damage. Currently most dates from Finnish LCT pegmatites are based on columbite-group minerals (CGMs), but their occurrence is restricted to mineralised zones within the pegmatites. Accessory minerals such as garnet and apatite are widespread in both mineralised and unmineralised LCT pegmatites. Lu–Hf dating of garnet and apatite provides an exceptional opportunity to better understand the geological history of these highly sought-after sources for battery and rare elements (Li, Nb, Ta, Be) that are critical for the green transition and its technology. In this paper we present the first successful in situ Lu–Hf garnet date of 1801 ± 53 Ma for an LCT pegmatite from the Kietyönmäki deposit in the Somero–Tammela pegmatite region, SW Finland. This age is consistent with previous zircon dates obtained for the region, ranging from 1815 to 1740 Ma with a weighted mean 207Pb / 206Pb age of 1786 ± 7 Ma.
{"title":"First in situ Lu–Hf garnet date for a lithium–caesium–tantalum (LCT) pegmatite from the Kietyönmäki Li deposit, Somero–Tammela pegmatite region, SW Finland","authors":"Krisztián Szentpéteri, K. Cutts, S. Glorie, Hugh O'Brien, Sari Lukkari, Michallik M. Radoslaw, Alan Butcher","doi":"10.5194/ejm-36-433-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-433-2024","url":null,"abstract":"Abstract. The in situ Lu–Hf geochronology of garnet, apatite, fluorite, and carbonate minerals is a fast-developing novel analytical method. It provides an alternative technique for age dating of accessory minerals in lithium–caesium–tantalum (LCT) rare-element (RE) pegmatites where zircon is often metamict due to alteration or radiation damage. Currently most dates from Finnish LCT pegmatites are based on columbite-group minerals (CGMs), but their occurrence is restricted to mineralised zones within the pegmatites. Accessory minerals such as garnet and apatite are widespread in both mineralised and unmineralised LCT pegmatites. Lu–Hf dating of garnet and apatite provides an exceptional opportunity to better understand the geological history of these highly sought-after sources for battery and rare elements (Li, Nb, Ta, Be) that are critical for the green transition and its technology. In this paper we present the first successful in situ Lu–Hf garnet date of 1801 ± 53 Ma for an LCT pegmatite from the Kietyönmäki deposit in the Somero–Tammela pegmatite region, SW Finland. This age is consistent with previous zircon dates obtained for the region, ranging from 1815 to 1740 Ma with a weighted mean 207Pb / 206Pb age of 1786 ± 7 Ma.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"15 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141271203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Sillimanite-bearing gneisses in the Romsdal region of the Western Gneiss Region (south Norway) have been investigated to document the presence, formation, composition and petrological evolution of the sillimanite-bearing assemblages. Sillimanite is found in augen gneiss, as nodular gneiss, and in well-foliated sillimanite–mica gneiss. Lenses and layers of eclogite occur within the gneiss units. The sillimanite-bearing gneisses are heterogranular and dominated by quartz, plagioclase (An29–41), K-feldspar and biotite (Mg# = 0.48–0.58; Ti = 0.16–0.36 a.p.f.u.), with variable amounts of white mica (Si = 6.1–6.3). K-feldspar occurs as porphyroclasts in augen gneiss, and garnet constitutes resorbed porphyroblasts. Garnet (Alm46–56Sps24–36Prp10−20Grs4–6; Mg# = 0.22–0.29) shows rimward-decreasing Mg#, together with a smaller grossular decrease and a marked spessartine increase up to Sps36. The foliation is defined by crystal-preferred-orientation micas, elongation of shape-preferred-orientation coarse K-feldspar phenocrysts and a modal banding of phases. Sillimanite occurs as coarse orientation-parallel matrix porphyroblasts, as finer grains and as fibrolitic aggregates. Quartz constitutes coarser elongated grains and monomineralic rods. Pseudosection modelling suggests that the peak-metamorphic mineral assemblage of garnet–sillimanite–feldspar–biotite–quartz–ilmenite–liquid equilibrated at temperatures up to 750 °C and pressures of 0.6 GPa. Subsequent retrogression consumed garnet. Mineral replacement and melt crystallization involved sillimanite, white mica, K-feldspar and quartz. The results document a metamorphic retrogression of the sillimanite gneisses in accordance with the presence of remnants of eclogites and high-pressure granulites in this northwestern part of the Western Gneiss Region.
{"title":"Metamorphic evolution of sillimanite gneiss in the high-pressure terrane of the Western Gneiss Region (Norway)","authors":"A. Engvik, Johannes Jakob","doi":"10.5194/ejm-36-345-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-345-2024","url":null,"abstract":"Abstract. Sillimanite-bearing gneisses in the Romsdal region of the Western Gneiss Region (south Norway) have been investigated to document the presence, formation, composition and petrological evolution of the sillimanite-bearing assemblages. Sillimanite is found in augen gneiss, as nodular gneiss, and in well-foliated sillimanite–mica gneiss. Lenses and layers of eclogite occur within the gneiss units. The sillimanite-bearing gneisses are heterogranular and dominated by quartz, plagioclase (An29–41), K-feldspar and biotite (Mg# = 0.48–0.58; Ti = 0.16–0.36 a.p.f.u.), with variable amounts of white mica (Si = 6.1–6.3). K-feldspar occurs as porphyroclasts in augen gneiss, and garnet constitutes resorbed porphyroblasts. Garnet (Alm46–56Sps24–36Prp10−20Grs4–6; Mg# = 0.22–0.29) shows rimward-decreasing Mg#, together with a smaller grossular decrease and a marked spessartine increase up to Sps36. The foliation is defined by crystal-preferred-orientation micas, elongation of shape-preferred-orientation coarse K-feldspar phenocrysts and a modal banding of phases. Sillimanite occurs as coarse orientation-parallel matrix porphyroblasts, as finer grains and as fibrolitic aggregates. Quartz constitutes coarser elongated grains and monomineralic rods. Pseudosection modelling suggests that the peak-metamorphic mineral assemblage of garnet–sillimanite–feldspar–biotite–quartz–ilmenite–liquid equilibrated at temperatures up to 750 °C and pressures of 0.6 GPa. Subsequent retrogression consumed garnet. Mineral replacement and melt crystallization involved sillimanite, white mica, K-feldspar and quartz. The results document a metamorphic retrogression of the sillimanite gneisses in accordance with the presence of remnants of eclogites and high-pressure granulites in this northwestern part of the Western Gneiss Region.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140375005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taehwan Kim, Yoonsup Kim, Simone Tumiati, Daeyeong Kim, Keewook Yi, Mi Jung Lee
Abstract. We investigated the mineral assemblage, mineral and bulk-rock chemistry, and zircon U–Pb age of a manganiferous quartzite layer in the Lanterman Range, northern Victoria Land, Antarctica. The mineral assemblage consists primarily of phengite and quartz, along with spessartine-rich garnet, Mn3+ and rare earth element–yttrium (REY)-zoned epidote-group minerals, and titanohematite. Mineral inclusions such as tephroite, rutile and pyrophanite are hosted in porphyroblasts of the latter three minerals and suggest prograde blueschist-facies to low-T eclogite-facies metamorphism (M1). Epidote-group minerals commonly exhibit multiple growth zones of piemontite and/or epidote (M1), REY-rich piemontite (M2), REY-rich epidote (M3), and epidote (M4) from core to rim. Pseudobinary fO2–X diagrams at constant P–T support the stability of an epidote-group mineral-bearing assemblage under highly oxidized conditions during prograde M2 to peak M3 metamorphism. In marked contrast, tephroite-bearing assemblages (M1) are limited to relatively reduced environments and Mn-rich, silica-deficient bulk-rock compositions. Mn nodules have such characteristics, and the contribution of this hydrogenous component is inferred from bulk-rock chemical features such as a strong positive Ce anomaly. The major-element composition of the manganiferous quartzite suggests a protolith primarily consisting of a mixture of chert and pelagic clay. The presence of rare detrital zircons supports terrigenous input from a craton and constrains the maximum time of deposition to be ca. 546 Ma. The lack of arc-derived detrital zircons in the quartzite and the predominance of siliciclastic metasedimentary rocks among the surrounding rocks suggest that the deep-sea protolith was most likely deposited in an arc/back-arc setting at a continental margin. High-P metamorphism associated with terrane accretion during the Ross orogeny took place in the middle Cambrian (ca. 506 Ma), broadly coeval with the metamorphic peak recorded in the associated high-P rocks such as mafic eclogites. Finally, it is noteworthy that the high-P manganiferous quartzite was amenable to exhumation because the paleo-position of the protolith was likely distal from the leading edge of the downgoing slab.
{"title":"Sedimentary protolith and high-P metamorphism of oxidized manganiferous quartzite from the Lanterman Range, northern Victoria Land, Antarctica","authors":"Taehwan Kim, Yoonsup Kim, Simone Tumiati, Daeyeong Kim, Keewook Yi, Mi Jung Lee","doi":"10.5194/ejm-36-323-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-323-2024","url":null,"abstract":"Abstract. We investigated the mineral assemblage, mineral and bulk-rock chemistry, and zircon U–Pb age of a manganiferous quartzite layer in the Lanterman Range, northern Victoria Land, Antarctica. The mineral assemblage consists primarily of phengite and quartz, along with spessartine-rich garnet, Mn3+ and rare earth element–yttrium (REY)-zoned epidote-group minerals, and titanohematite. Mineral inclusions such as tephroite, rutile and pyrophanite are hosted in porphyroblasts of the latter three minerals and suggest prograde blueschist-facies to low-T eclogite-facies metamorphism (M1). Epidote-group minerals commonly exhibit multiple growth zones of piemontite and/or epidote (M1), REY-rich piemontite (M2), REY-rich epidote (M3), and epidote (M4) from core to rim. Pseudobinary fO2–X diagrams at constant P–T support the stability of an epidote-group mineral-bearing assemblage under highly oxidized conditions during prograde M2 to peak M3 metamorphism. In marked contrast, tephroite-bearing assemblages (M1) are limited to relatively reduced environments and Mn-rich, silica-deficient bulk-rock compositions. Mn nodules have such characteristics, and the contribution of this hydrogenous component is inferred from bulk-rock chemical features such as a strong positive Ce anomaly. The major-element composition of the manganiferous quartzite suggests a protolith primarily consisting of a mixture of chert and pelagic clay. The presence of rare detrital zircons supports terrigenous input from a craton and constrains the maximum time of deposition to be ca. 546 Ma. The lack of arc-derived detrital zircons in the quartzite and the predominance of siliciclastic metasedimentary rocks among the surrounding rocks suggest that the deep-sea protolith was most likely deposited in an arc/back-arc setting at a continental margin. High-P metamorphism associated with terrane accretion during the Ross orogeny took place in the middle Cambrian (ca. 506 Ma), broadly coeval with the metamorphic peak recorded in the associated high-P rocks such as mafic eclogites. Finally, it is noteworthy that the high-P manganiferous quartzite was amenable to exhumation because the paleo-position of the protolith was likely distal from the leading edge of the downgoing slab.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"07 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140377551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Holtstam, Jörgen Langhof, Henrik Friis, Andreas Karlsson, Muriel Erambert
Abstract. The two new minerals igelströmite, Fe3+(Sb3+Pb2+)O4, and manganoschafarzikite, Mn2+Sb23+O4, are found in the Långban Fe–Mn deposit, in open fractures in a fine-grained hematite ore, with minor amounts of aegirine, a serpentine-group mineral, fluorcalcioroméite, baryte, nadorite, mimetite and other late-stage minerals. Igelströmite is named after the Swedish geologist–mineralogist Lars Johan Igelström (1822–1897). Mohs hardness = 3–4 and Dcalc= 6.33(1) and 5.37(2) g cm−3 for igelströmite and manganoschafarzikite, respectively. Cleavage is distinct on {110}. Both minerals are brittle, with an uneven to conchoidal fracture. The chemical formulae obtained from microprobe data are (Fe0.593+Mn0.292+As0.063+Fe0.062+)Σ=1.00(Sb1.243+Pb0.652+As0.113+)Σ=2.00O4 and (Mn0.642+Fe0.252+Mg0.08)Σ=0.97(Sb1.973+As0.033+Pb0.012+)Σ=2.01O4. The crystal structures for igelströmite and manganoschafarzikite have been refined in space group P42/mbc from single-crystal X-ray diffraction data to R1 = 3.73 % and 1.51 %, respectively, giving the following sets of unit-cell parameters: a= 8.4856(2), 8.65159(8) Å; c= 6.0450(3), 5.97175(9); and V= 435.27(3), 446.986(11) Å3 for Z = 4. Both minerals are isostructural with minium, Pb4+Pb22+O4, where Pb4+O6 forms distorted octahedra, which connect via trans-edges to form rutile-like ribbons along c. The Pb2+ atoms appear in trigonal, flattened PbO3 pyramids, which are linked via corners to form zigzag (PbO2)n chains. The minium group, of general formula MX2O4(X= As3+, Sb3+, Pb2+), presently consists of the minerals minium, trippkeite, schafarzikite, igelströmite and manganoschafarzikite. For future new members, it is recommended to consider the X cation content for the root name and add prefixes to indicate the dominant metal at the M position.
摘要。在Långban铁-锰矿床中发现了两种新矿物igelströmite（Fe3+(Sb3+Pb2+)O4）和manganoschafarzikite（Mn2+Sb23+O4），它们位于细粒赤铁矿矿石的开口裂隙中，并含有少量蛇纹石族矿物egirine、氟钙铈镧矿、重晶石、呐多罗铁矿、拟锰矿和其他晚期矿物。伊格尔斯特罗姆岩是以瑞典地质矿物学家拉尔斯-约翰-伊格尔斯特罗姆（1822-1897 年）的名字命名的。igelströmite和manganoschafarzikite的莫氏硬度= 3-4，Dcalc= 6.33(1) 和 5.37(2) g cm-3。{110}上的裂隙明显。这两种矿物都很脆，断口不平整，呈圆锥形。微探针数据得出的化学式为 (Fe0.593+Mn0.292+As0.063+Fe0.062+)Σ=1.00(Sb1.243+Pb0.652+As0.113+)Σ=2.00O4 and (Mn0.642+Fe0.252+Mg0.08)Σ=0.97(Sb1.973+As0.033+Pb0.012+)Σ=2.01O4.根据单晶 X 射线衍射数据，igelströmite 和 manganoschafarzikite 的晶体结构在空间群 P42/mbc 中分别细化为 R1 = 3.73 % 和 1.根据单晶 X 射线衍射数据，空间群 P42/mbc 的 R1 = 3.73 % 和 R1 = 1.51 % 分别得到以下几组单胞参数：a= 8.4856(2)，8.65159(8) Å；c= 6.0450(3)，5.97175(9)；Z = 4 时，V= 435.27(3)，446.986(11) Å3。这两种矿物与minium（Pb4+Pb22+O4）同构，其中 Pb4+O6 形成扭曲的八面体，通过反角连接，沿 c 形成类似金红石的带状。minium 族的通式为 MX2O4（X= As3+、Sb3+、Pb2+），目前包括 minium、trippkeite、schafarzikite、igelströmite 和 manganoschafarzikite 等矿物。对于未来的新成员，建议考虑根名称中的 X 阳离子含量，并添加前缀以表示 M 位置上的主要金属。
{"title":"Igelströmite, Fe3+(Sb3+Pb2+)O4, and manganoschafarzikite, Mn2+Sb3+2O4, two new members of the newly established minium group, from the Långban Mn–Fe deposit, Värmland, Sweden","authors":"D. Holtstam, Jörgen Langhof, Henrik Friis, Andreas Karlsson, Muriel Erambert","doi":"10.5194/ejm-36-311-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-311-2024","url":null,"abstract":"Abstract. The two new minerals igelströmite, Fe3+(Sb3+Pb2+)O4, and manganoschafarzikite, Mn2+Sb23+O4, are found in the Långban Fe–Mn deposit, in open fractures in a fine-grained hematite ore, with minor amounts of aegirine, a serpentine-group mineral, fluorcalcioroméite, baryte, nadorite, mimetite and other late-stage minerals. Igelströmite is named after the Swedish geologist–mineralogist Lars Johan Igelström (1822–1897). Mohs hardness = 3–4 and Dcalc= 6.33(1) and 5.37(2) g cm−3 for igelströmite and manganoschafarzikite, respectively. Cleavage is distinct on {110}. Both minerals are brittle, with an uneven to conchoidal fracture. The chemical formulae obtained from microprobe data are (Fe0.593+Mn0.292+As0.063+Fe0.062+)Σ=1.00(Sb1.243+Pb0.652+As0.113+)Σ=2.00O4 and (Mn0.642+Fe0.252+Mg0.08)Σ=0.97(Sb1.973+As0.033+Pb0.012+)Σ=2.01O4. The crystal structures for igelströmite and manganoschafarzikite have been refined in space group P42/mbc from single-crystal X-ray diffraction data to R1 = 3.73 % and 1.51 %, respectively, giving the following sets of unit-cell parameters: a= 8.4856(2), 8.65159(8) Å; c= 6.0450(3), 5.97175(9); and V= 435.27(3), 446.986(11) Å3 for Z = 4. Both minerals are isostructural with minium, Pb4+Pb22+O4, where Pb4+O6 forms distorted octahedra, which connect via trans-edges to form rutile-like ribbons along c. The Pb2+ atoms appear in trigonal, flattened PbO3 pyramids, which are linked via corners to form zigzag (PbO2)n chains. The minium group, of general formula MX2O4(X= As3+, Sb3+, Pb2+), presently consists of the minerals minium, trippkeite, schafarzikite, igelströmite and manganoschafarzikite. For future new members, it is recommended to consider the X cation content for the root name and add prefixes to indicate the dominant metal at the M position.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":" 536","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140383130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Lykova, R. Rowe, G. Poirier, Henrik Friis, Kate Helwig
Abstract. The new mckelveyite group mineral, alicewilsonite-(YLa), Na2Sr2YLa(CO3)6 ⋅ 3H2O, was found together with kamphaugite-(Y), paratooite-(Y), bastnäsite-(La), and decrespignyite-(Y) coating along fractures in dolomite at the Paratoo copper mine, South Australia, Australia. It occurs as pale pink to colourless pseudohexagonal tabular crystals up to 150 µm in size. The streak is white; the lustre is vitreous. The mineral has no cleavage. Dcalc is 3.37 g cm−3. Alicewilsonite-(YLa) is optically biaxial (−), α = 1.556(2), β= 1.582(2), γ= 1.592(2), 2V (meas.) = 60(2)°, 2V (calc.) = 63° (589 nm). The IR spectrum is reported. The composition (wt %, average of seven analyses) is Na2O 7.43, CaO 2.00, SrO 18.43, BaO 1.64, Y2O3 9.59, La2O3 11.74, Pr2O3 1.29, Nd2O3 5.74, Sm2O3 0.44, Eu2O3 0.09, Gd2O3 0.95, Dy2O3 1.15, Ho2O3 0.25, Er2O3 0.89, Yb2O3 0.29, CO2 29.78, H2O 6.18, total 97.88. The empirical formula calculated on the basis of six cations with 3 H2O molecules is as follows: Na2.10Ca0.31Sr1.56Ba0.10Y0.74La0.63Pr0.07 Nd0.30Sm0.03Eu0.01Gd0.04Dy0.05Ho0.01Er0.04 Yb0.01(CO3)5.92(H2O)3. The mineral is triclinic, P1, a= 8.9839(2), b= 8.9728(3), c= 6.7441(2) Å, α= 102.812(2)°, β= 116.424(2)°, γ= 60.128(2)°, and V= 422.17(2) Å3 and Z= 1. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 6.03(43)(001), 4.355(100)(11‾0, 2‾1‾1, 120), 4.020(30)(1‾11, 210, 1‾2‾1), 3.188(29)(2‾1‾2, 11‾1, 121), 2.819(96)(002, 1‾12, 211, 1‾2‾2), 2.592(40)(3‾01, 030, 3‾3‾1), 2.228(33)(2‾21, 4‾2‾1, 2‾4‾1). 2.011(36)(2‾22, 003, 420, 2‾4‾2), 1.9671(32)(3‾03, 301, 03‾2, 032, 3‾3‾3, 331). The crystal structure was solved and refined from single-crystal X-ray diffraction data (R1= 0.058).
{"title":"Mckelveyite group minerals – Part 4: Alicewilsonite-(YLa), Na2Sr2YLa(CO3)6 ⋅ 3H2O, a new lanthanum-dominant species from the Paratoo mine, Australia","authors":"I. Lykova, R. Rowe, G. Poirier, Henrik Friis, Kate Helwig","doi":"10.5194/ejm-36-301-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-301-2024","url":null,"abstract":"Abstract. The new mckelveyite group mineral, alicewilsonite-(YLa), Na2Sr2YLa(CO3)6 ⋅ 3H2O, was found together with kamphaugite-(Y), paratooite-(Y), bastnäsite-(La), and decrespignyite-(Y) coating along fractures in dolomite at the Paratoo copper mine, South Australia, Australia. It occurs as pale pink to colourless pseudohexagonal tabular crystals up to 150 µm in size. The streak is white; the lustre is vitreous. The mineral has no cleavage. Dcalc is 3.37 g cm−3. Alicewilsonite-(YLa) is optically biaxial (−), α = 1.556(2), β= 1.582(2), γ= 1.592(2), 2V (meas.) = 60(2)°, 2V (calc.) = 63° (589 nm). The IR spectrum is reported. The composition (wt %, average of seven analyses) is Na2O 7.43, CaO 2.00, SrO 18.43, BaO 1.64, Y2O3 9.59, La2O3 11.74, Pr2O3 1.29, Nd2O3 5.74, Sm2O3 0.44, Eu2O3 0.09, Gd2O3 0.95, Dy2O3 1.15, Ho2O3 0.25, Er2O3 0.89, Yb2O3 0.29, CO2 29.78, H2O 6.18, total 97.88. The empirical formula calculated on the basis of six cations with 3 H2O molecules is as follows: Na2.10Ca0.31Sr1.56Ba0.10Y0.74La0.63Pr0.07 Nd0.30Sm0.03Eu0.01Gd0.04Dy0.05Ho0.01Er0.04 Yb0.01(CO3)5.92(H2O)3. The mineral is triclinic, P1, a= 8.9839(2), b= 8.9728(3), c= 6.7441(2) Å, α= 102.812(2)°, β= 116.424(2)°, γ= 60.128(2)°, and V= 422.17(2) Å3 and Z= 1. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 6.03(43)(001), 4.355(100)(11‾0, 2‾1‾1, 120), 4.020(30)(1‾11, 210, 1‾2‾1), 3.188(29)(2‾1‾2, 11‾1, 121), 2.819(96)(002, 1‾12, 211, 1‾2‾2), 2.592(40)(3‾01, 030, 3‾3‾1), 2.228(33)(2‾21, 4‾2‾1, 2‾4‾1). 2.011(36)(2‾22, 003, 420, 2‾4‾2), 1.9671(32)(3‾03, 301, 03‾2, 032, 3‾3‾3, 331). The crystal structure was solved and refined from single-crystal X-ray diffraction data (R1= 0.058).\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140214090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Borghini, S. Ferrero, Patrick J. O'Brien, Bernd Wunder, Peter Tollan, J. Majka, Rico Fuchs, Kerstin Gresky
Abstract. Primary granitic melt inclusions are trapped in garnets of eclogites in the garnet peridotite body of Pfaffenberg, Granulitgebirge (Bohemian Massif, Germany). These polycrystalline inclusions, based on their nature and composition, can be called nanogranitoids and contain mainly phlogopite/biotite, kumdykolite, quartz/rare cristobalite, a phase with the main Raman peak at 412 cm−1, a phase with the main Raman peak at 430 cm−1, osumilite and plagioclase. The melt is hydrous, peraluminous and granitic and significantly enriched in large ion lithophile elements (LILE), Th, U, Li, B and Pb. The melt major element composition resembles that of melts produced by the partial melting of metasediments, as also supported by its trace element signature characterized by elements (LILE, Pb, Li and B) typical of the continental crust. These microstructural and geochemical features suggest that the investigated melt originated in the subducted continental crust and interacted with the mantle to produce the Pfaffenberg eclogite. Moreover, in situ analyses and calculations based on partition coefficients between apatite and melt show that the melt was also enriched in Cl and F, pointing toward the presence of a brine during melting. The melt preserved in inclusions can thus be regarded as an example of a metasomatizing agent present at depth and responsible for the interaction between the crust and the mantle. Chemical similarities between this melt and other metasomatizing melts measured in other eclogites from the Granulitgebirge and Erzgebirge, in addition to the overall similar enrichment in trace elements observed in other metasomatized mantle rocks from central Europe, suggest an extended crustal contamination of the mantle beneath the Bohemian Massif during the Variscan orogeny.
{"title":"Halogen-bearing metasomatizing melt preserved in high-pressure (HP) eclogites of Pfaffenberg, Bohemian Massif","authors":"A. Borghini, S. Ferrero, Patrick J. O'Brien, Bernd Wunder, Peter Tollan, J. Majka, Rico Fuchs, Kerstin Gresky","doi":"10.5194/ejm-36-279-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-279-2024","url":null,"abstract":"Abstract. Primary granitic melt inclusions are trapped in garnets of eclogites in the garnet peridotite body of Pfaffenberg, Granulitgebirge (Bohemian Massif, Germany). These polycrystalline inclusions, based on their nature and composition, can be called nanogranitoids and contain mainly phlogopite/biotite, kumdykolite, quartz/rare cristobalite, a phase with the main Raman peak at 412 cm−1, a phase with the main Raman peak at 430 cm−1, osumilite and plagioclase. The melt is hydrous, peraluminous and granitic and significantly enriched in large ion lithophile elements (LILE), Th, U, Li, B and Pb. The melt major element composition resembles that of melts produced by the partial melting of metasediments, as also supported by its trace element signature characterized by elements (LILE, Pb, Li and B) typical of the continental crust. These microstructural and geochemical features suggest that the investigated melt originated in the subducted continental crust and interacted with the mantle to produce the Pfaffenberg eclogite. Moreover, in situ analyses and calculations based on partition coefficients between apatite and melt show that the melt was also enriched in Cl and F, pointing toward the presence of a brine during melting. The melt preserved in inclusions can thus be regarded as an example of a metasomatizing agent present at depth and responsible for the interaction between the crust and the mantle. Chemical similarities between this melt and other metasomatizing melts measured in other eclogites from the Granulitgebirge and Erzgebirge, in addition to the overall similar enrichment in trace elements observed in other metasomatized mantle rocks from central Europe, suggest an extended crustal contamination of the mantle beneath the Bohemian Massif during the Variscan orogeny.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"21 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140239035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ian E. Grey, Christian Rewitzer, R. Hochleitner, A. R. Kampf, Stephanie Boer, W. G. Mumme, Nicholas C. Wilson
Abstract. Macraeite, [(H2O)K]Mn2(Fe2Ti)(PO4)4[O(OH)](H2O)10 ⋅ 4H2O, is a new monoclinic member of the paulkerrite group, from the Cubos–Mesquitela–Mangualde pegmatite, Mangualde, Portugal. It was found in phosphate nodules of weathered triplite, heterosite, and lithiophilite. Associated minerals are strengite, triplite, bermanite, phosphosiderite, and switzerite. Macraeite forms colourless to light-greenish-yellow pseudo-rhombic dodecahedral-shaped crystals up to 0.15 mm. The crystals are equant with forms {010}, {001}, {111}, and {1‾11}. The calculated density is 2.39 g cm−3. Optically, macraeite crystals are biaxial (+), with α=1.605(3), β=1.611(3), γ=1.646(3) (measured in white light), and 2V(meas) = 45(3)°. The empirical formula from electron microprobe analyses and structure refinement is A1[(H2O)0.83K0.17]Σ1.00 A2[K0.65(H2O)0.35]Σ1.00 M1(Mn1.98□0.022+)Σ2.00 M2(Fe1.093+Al0.31Ti0.524+Mg0.08)Σ2.00 M3(Ti0.664+Fe0.343+)Σ1.00 (PO4)4 X[O0.87F0.53(OH)0.60]Σ2.00(H2O)10 ⋅ 4H2O. Macraeite has monoclinic symmetry with space group P21/c and unit-cell parameters a=10.562(2) Å, b=20.725(4) Å, c=12.416(2) Å, β=90.09(3)°, V=2717.8(9) Å3, and Z=4. The crystal structure was refined using synchrotron single-crystal data to wRobs=0.065 for 4990 reflections with I>3σ(I). Macraeite is isostructural with the paulkerrite-group minerals rewitzerite and paulkerrite, with ordering of K and H2O at different A sites (A1 and A2) of the general formula A1A2M12M22M3(PO4)4X2(H2O)10 ⋅ 4H2O, whereas in the orthorhombic member, benyacarite, K and H2O are disordered at a single A site.
{"title":"Macraeite, [(H2O)K]Mn2(Fe2Ti)(PO4)4[O(OH)](H2O)10 ⋅ 4H2O, a new monoclinic paulkerrite-group mineral, from the Cubos–Mesquitela–Mangualde pegmatite, Portugal","authors":"Ian E. Grey, Christian Rewitzer, R. Hochleitner, A. R. Kampf, Stephanie Boer, W. G. Mumme, Nicholas C. Wilson","doi":"10.5194/ejm-36-267-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-267-2024","url":null,"abstract":"Abstract. Macraeite, [(H2O)K]Mn2(Fe2Ti)(PO4)4[O(OH)](H2O)10 ⋅ 4H2O, is a new monoclinic member of the paulkerrite group, from the Cubos–Mesquitela–Mangualde pegmatite, Mangualde, Portugal. It was found in phosphate nodules of weathered triplite, heterosite, and lithiophilite. Associated minerals are strengite, triplite, bermanite, phosphosiderite, and switzerite. Macraeite forms colourless to light-greenish-yellow pseudo-rhombic dodecahedral-shaped crystals up to 0.15 mm. The crystals are equant with forms {010}, {001}, {111}, and {1‾11}. The calculated density is 2.39 g cm−3. Optically, macraeite crystals are biaxial (+), with α=1.605(3), β=1.611(3), γ=1.646(3) (measured in white light), and 2V(meas) = 45(3)°. The empirical formula from electron microprobe analyses and structure refinement is A1[(H2O)0.83K0.17]Σ1.00 A2[K0.65(H2O)0.35]Σ1.00\u0000M1(Mn1.98□0.022+)Σ2.00 M2(Fe1.093+Al0.31Ti0.524+Mg0.08)Σ2.00 M3(Ti0.664+Fe0.343+)Σ1.00 (PO4)4 X[O0.87F0.53(OH)0.60]Σ2.00(H2O)10 ⋅ 4H2O. Macraeite has monoclinic symmetry with space group P21/c and unit-cell parameters a=10.562(2) Å, b=20.725(4) Å, c=12.416(2) Å, β=90.09(3)°, V=2717.8(9) Å3, and Z=4. The crystal structure was refined using synchrotron single-crystal data to wRobs=0.065 for 4990 reflections with I>3σ(I). Macraeite is isostructural with the paulkerrite-group minerals rewitzerite and paulkerrite, with ordering of K and H2O at different A sites (A1 and A2) of the general formula A1A2M12M22M3(PO4)4X2(H2O)10 ⋅ 4H2O, whereas in the orthorhombic member, benyacarite, K and H2O are disordered at a single A site.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"1984 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140246793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Pichavant, A. Villaros, J. Michaud, B. Scaillet
Abstract. Current granite magma generation models essentially reduce to two groups: (1) intra-crustal melting and (2) basaltic origin. A mixed, crustal, and basaltic origin and therefore a mantle filiation has been proposed for most granite magma types. In contrast, strongly peraluminous silicic magmas such as two-mica leucogranites have been classically interpreted as products of pure crustal melting. In this paper, we re-examine this interpretation and the evidence for considering leucogranites as unique among granite types. In the first part, some key aspects of the intra-crustal melting model are reviewed. Classical assumptions are discussed, such as the use of migmatites to infer granite generation processes. Our knowledge of crustal melt production is still incomplete, and fluid-present H2O-undersaturated melting should be considered in addition to mica dehydration melting reactions. The source rock remains essential as a concept despite difficulties in the identification of source lithologies from their geochemical and mineralogical signatures. Incorporating spatial and temporal variability at the source and the possibility of external inputs (fluids, magmas) would represent useful evolutions of the model. Thermal considerations bring strong constraints on the intra-crustal melting model since the absence of mafic magmas reduces possible external heat sources for melting. In the second part, the origin of a strongly peraluminous silicic volcanic suite, the Macusani Volcanics (SE Peru), is detailed. Magmas were generated in a mid-crustal anatectic zone characterized by high temperatures and heat fluxes. Crustal metamorphic rocks (metapelites) were dominant in the source region, although Ba-, Sr- and La-rich calcic plagioclase cores and some biotite and sanidine compositions point to the involvement of a mantle component. The heat necessary for melting was supplied by mafic mainly potassic–ultrapotassic magmas which also partly mixed and hybridized with the crustal melts. The Macusani Volcanics provide an example of a crustal peraluminous silicic suite generated with a contribution from the mantle in the form of mafic magmas intruded in the source region. This, as well as the limitations of the intra-crustal melting model, establishes that a mantle filiation is possible for peraluminous leucogranites as for most other crustal (S-, I- and A-type) peraluminous and metaluminous granites. This stresses the critical importance of the mantle for granite generation and opens the way for unification of granite generation processes.
摘要。目前的花岗岩岩浆生成模型主要分为两类：（1）地壳内熔融；（2）玄武岩成因。大多数花岗岩岩浆类型被认为是地壳和玄武岩的混合起源，因此也被认为是地幔的分枝。相比之下，强高铝硅质岩浆（如双云母白花岗岩）则被经典地解释为纯地壳熔融的产物。在本文中，我们重新审视了这一解释，以及将白花岗岩视为花岗岩类型中独一无二的证据。第一部分回顾了地壳内部熔融模型的一些关键方面。讨论了一些经典假设，如利用偏闪长岩推断花岗岩的生成过程。我们对地壳熔融生成的了解仍不全面，除了云母脱水熔融反应外，还应考虑流体存在的 H2O 不饱和熔融。尽管从地球化学和矿物学特征识别源岩性存在困难，但源岩仍然是一个重要的概念。将源岩的空间和时间变化以及外部输入（流体、岩浆）的可能性纳入模型，将是模型的有益发展。由于缺乏钙质岩浆，减少了可能的外部熔化热源，因此热因素对岩壳内熔化模型产生了强烈的制约。第二部分详细介绍了马库萨尼火山岩（秘鲁东南部）这一强过铝硅质火山岩群的起源。岩浆产生于以高温和热通量为特征的中地壳无极带。尽管富含钡、锶和镭的钙斜长石岩芯以及一些生物闪长岩和辉长岩成分表明有地幔成分的参与，但地壳变质岩（玄武岩）在源区占主导地位。熔化所需的热量主要由黑云母岩浆提供，其中主要是钾质-超钾质岩浆，这些岩浆也部分与地壳熔体混合和杂化。马库萨尼火山岩提供了一个实例，说明地壳高铝硅质岩套的生成有地幔的参与，其形式是在源区侵入的钙质岩浆。这一点，以及地壳内部熔融模型的局限性，确定了白云母高铝酸盐岩与大多数其他地壳（S 型、I 型和 A 型）高铝和金属铝花岗岩一样，可能存在地幔分异。这强调了地幔对花岗岩生成的至关重要性，并为统一花岗岩生成过程开辟了道路。
{"title":"Granite magmatism and mantle filiation","authors":"M. Pichavant, A. Villaros, J. Michaud, B. Scaillet","doi":"10.5194/ejm-36-225-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-225-2024","url":null,"abstract":"Abstract. Current granite magma generation models essentially reduce to two groups: (1) intra-crustal melting and (2) basaltic origin. A mixed, crustal, and basaltic origin and therefore a mantle filiation has been proposed for most granite magma types. In contrast, strongly peraluminous silicic magmas such as two-mica leucogranites have been classically interpreted as products of pure crustal melting. In this paper, we re-examine this interpretation and the evidence for considering leucogranites as unique among granite types. In the first part, some key aspects of the intra-crustal melting model are reviewed. Classical assumptions are discussed, such as the use of migmatites to infer granite generation processes. Our knowledge of crustal melt production is still incomplete, and fluid-present H2O-undersaturated melting should be considered in addition to mica dehydration melting reactions. The source rock remains essential as a concept despite difficulties in the identification of source lithologies from their geochemical and mineralogical signatures. Incorporating spatial and temporal variability at the source and the possibility of external inputs (fluids, magmas) would represent useful evolutions of the model. Thermal considerations bring strong constraints on the intra-crustal melting model since the absence of mafic magmas reduces possible external heat sources for melting. In the second part, the origin of a strongly peraluminous silicic volcanic suite, the Macusani Volcanics (SE Peru), is detailed. Magmas were generated in a mid-crustal anatectic zone characterized by high temperatures and heat fluxes. Crustal metamorphic rocks (metapelites) were dominant in the source region, although Ba-, Sr- and La-rich calcic plagioclase cores and some biotite and sanidine compositions point to the involvement of a mantle component. The heat necessary for melting was supplied by mafic mainly potassic–ultrapotassic magmas which also partly mixed and hybridized with the crustal melts. The Macusani Volcanics provide an example of a crustal peraluminous silicic suite generated with a contribution from the mantle in the form of mafic magmas intruded in the source region. This, as well as the limitations of the intra-crustal melting model, establishes that a mantle filiation is possible for peraluminous leucogranites as for most other crustal (S-, I- and A-type) peraluminous and metaluminous granites. This stresses the critical importance of the mantle for granite generation and opens the way for unification of granite generation processes.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"15 43","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140442971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Micro-Raman spectroscopy was used to determine the inclusions in magmatic zircon from the Late Cretaceous A-type acid igneous rocks in the Slavonian mountains (Mt. Papuk and Mt. Požeška Gora), in the southwestern part of the Pannonian Basin (Croatia). The mineral inclusions detected in the early-crystallised zircon are anatase, apatite, hematite, ilmenite and possibly magnetite. Numerous melt inclusions comprise albite, cristobalite, hematite, kaolinite, K-feldspar, kokchetavite, kumdykolite muscovite and quartz, where this mineral association is characteristic of so-called nanorocks (nanogranites), commonly found in peritectic garnets from high-grade metamorphic rocks. Here we present the first finding of kokchetavite and kumdykolite in a magmatic zircon. Together with anatase and hematite, these polymorphs are likely evidence of rapid uplift and consequent rapid cooling of hot oxidised magma generated in the lower crust and its emplacement in the upper crustal level. This finding provides further confirmation that kumdykolite and kokchetavite do not require ultra-high pressure (UHP) to form and should not be considered exclusively UHP phases. The rapid uplift was possible due to the formation of accompanying extensional deep rifts during the tectonic transition from compression to extension, associated with the closure of the Neotethys Ocean in the area of present-day Slavonian mountains in the Late Cretaceous (∼82 Ma).
摘要利用微拉曼光谱测定了潘诺尼亚盆地（克罗地亚）西南部斯拉沃尼亚山脉（Papuk 山和 Požeška Gora 山）晚白垩世 A 型酸性火成岩中岩浆锆石的包裹体。在早期结晶的锆石中检测到的矿物包裹体有锐钛矿、磷灰石、赤铁矿、钛铁矿，可能还有磁铁矿。大量的熔融包裹体包括白云石、钙钛矿、赤铁矿、高岭石、K 长石、kokchetavite、kumdykolite muscovite 和石英，这种矿物关联是所谓的纳米岩的特征，常见于高品位变质岩的包晶石榴石中。在这里，我们首次在岩浆锆石中发现了kokchetavite和kumdykolite。这些多晶体与锐钛矿和赤铁矿一起，很可能是下地壳中产生的热氧化岩浆快速隆升并随之快速冷却，然后在上地壳层位移的证据。这一发现进一步证实了kumdykolite和kokchetavite的形成并不需要超高压（UHP），因此不应被视为纯粹的超高压相。在白垩纪晚期（82 千兆年前），新特提斯洋在今天斯拉沃尼亚山脉地区闭合，在构造从压缩向延伸转变的过程中，伴随着延伸性深裂谷的形成，快速隆起成为可能。
{"title":"Inclusions in magmatic zircon from Slavonian mountains (eastern Croatia): anatase, kumdykolite and kokchetavite and implications for the magmatic evolution","authors":"Petra Schneider, D. Balen","doi":"10.5194/ejm-36-209-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-209-2024","url":null,"abstract":"Abstract. Micro-Raman spectroscopy was used to determine the inclusions in magmatic zircon from the Late Cretaceous A-type acid igneous rocks in the Slavonian mountains (Mt. Papuk and Mt. Požeška Gora), in the southwestern part of the Pannonian Basin (Croatia). The mineral inclusions detected in the early-crystallised zircon are anatase, apatite, hematite, ilmenite and possibly magnetite. Numerous melt inclusions comprise albite, cristobalite, hematite, kaolinite, K-feldspar, kokchetavite, kumdykolite muscovite and quartz, where this mineral association is characteristic of so-called nanorocks (nanogranites), commonly found in peritectic garnets from high-grade metamorphic rocks. Here we present the first finding of kokchetavite and kumdykolite in a magmatic zircon. Together with anatase and hematite, these polymorphs are likely evidence of rapid uplift and consequent rapid cooling of hot oxidised magma generated in the lower crust and its emplacement in the upper crustal level. This finding provides further confirmation that kumdykolite and kokchetavite do not require ultra-high pressure (UHP) to form and should not be considered exclusively UHP phases. The rapid uplift was possible due to the formation of accompanying extensional deep rifts during the tectonic transition from compression to extension, associated with the closure of the Neotethys Ocean in the area of present-day Slavonian mountains in the Late Cretaceous (∼82 Ma).\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"49 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140452335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Malcherek, B. Mihailova, Jochen Schlüter, Philippe Roth, N. Meisser
Abstract. The new mineral heimite (IMA2022-019), PbCu2(AsO4)(OH)3 ⋅ 2H2O, was found at the Grosses Chalttal deposit, Mürtschenalp district, Glarus, Switzerland, where it occurs as a secondary mineral associated mainly with bayldonite and chrysocolla. Heimite forms lath-like, prismatic transparent crystals of green or pale-blue colour. It has a pale-green streak and a vitreous-to-silky lustre. The calculated density is 4.708 g cm−3. The empirical formula based on nine O atoms per formula unit is Pb1.04Ca0.03Cu2.10As1.10H6.14O9. Heimite is pseudo-orthorhombic, with monoclinic symmetry; space group P21/n; and unit cell parameters a=5.9132(5), b=7.8478(6) and c=16.8158(15) Å and β=90.007(6)∘, V=780.33(8) Å3 and Z=4. The five strongest lines in the calculated powder diffraction pattern are (d in Å(I)hkl) as follows: 8.425(100)002, 3.713(60)014, 3.276(54)120, 3.221(42)023 and 2.645(61)016. The crystal structure, refined to R1=2.75 % for 1869 reflections with I>3σ(I), is based on chains of edge-sharing, Jahn–Teller-distorted CuO6 octahedra, laterally connected by AsO4 tetrahedra and sixfold coordinated Pb atoms. The resulting layers are stacked along [001]. Interlayer hydrogen bonding is mediated by hydrogen atoms that belong to OH groups and to H2O, mutually participating in the Cu coordination. The crystal structure of heimite is related to that of duftite, and both minerals are found epitactically intergrown at the type locality.
{"title":"Heimite, PbCu2(AsO4)(OH)3 ⋅ 2H2O, a new mineral from the Grosses Chalttal deposit, Switzerland","authors":"T. Malcherek, B. Mihailova, Jochen Schlüter, Philippe Roth, N. Meisser","doi":"10.5194/ejm-36-153-2024","DOIUrl":"https://doi.org/10.5194/ejm-36-153-2024","url":null,"abstract":"Abstract. The new mineral heimite (IMA2022-019), PbCu2(AsO4)(OH)3 ⋅ 2H2O, was found at the Grosses Chalttal deposit, Mürtschenalp district, Glarus, Switzerland, where it occurs as a secondary mineral associated mainly with bayldonite and chrysocolla. Heimite forms lath-like, prismatic transparent crystals of green or pale-blue colour. It has a pale-green streak and a vitreous-to-silky lustre. The calculated density is 4.708 g cm−3. The empirical formula based on nine O atoms per formula unit is Pb1.04Ca0.03Cu2.10As1.10H6.14O9. Heimite is pseudo-orthorhombic, with monoclinic symmetry; space group P21/n; and unit cell parameters a=5.9132(5), b=7.8478(6) and c=16.8158(15) Å and β=90.007(6)∘, V=780.33(8) Å3 and Z=4. The five strongest lines in the calculated powder diffraction pattern are (d in Å(I)hkl) as follows: 8.425(100)002, 3.713(60)014, 3.276(54)120, 3.221(42)023 and 2.645(61)016. The crystal structure, refined to R1=2.75 % for 1869 reflections with I>3σ(I), is based on chains of edge-sharing, Jahn–Teller-distorted CuO6 octahedra, laterally connected by AsO4 tetrahedra and sixfold coordinated Pb atoms. The resulting layers are stacked along [001]. Interlayer hydrogen bonding is mediated by hydrogen atoms that belong to OH groups and to H2O, mutually participating in the Cu coordination. The crystal structure of heimite is related to that of duftite, and both minerals are found epitactically intergrown at the type locality.\u0000","PeriodicalId":507154,"journal":{"name":"European Journal of Mineralogy","volume":"158 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140482317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：