Canadian Mineralogist最新文献

{"title":"In memoriam: Tomas Feininger (1935–2019)","authors":"R. Martin","doi":"10.3749/canmin.obit00007","DOIUrl":"https://doi.org/10.3749/canmin.obit00007","url":null,"abstract":"","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"287-288"},"PeriodicalIF":0.9,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.obit00007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47555632","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":"The central portions of the Cu–Fe–Se phase system at temperatures from 900 to 300 °C","authors":"E. Makovicky, S. Karup-moller","doi":"10.3749/canmin.1900071","DOIUrl":"https://doi.org/10.3749/canmin.1900071","url":null,"abstract":"\u0000 The central portions of the condensed phase system Cu–Fe–Se were investigated by means of dry syntheses in evacuated silica glass tubes at 900, 750, 600, 500, 450, 350, and 300 °C. Synthesis products were studied by reflected-light microscopy and electron microprobe analyses. The field of sulfide melt is extensive at 900 °C and retreats progressively towards the Cu–Se side at 750 °C; residual selenide melt persists at 600 °C. The selenium analogue of iss was found only at and below 600 °C; eskebornite becomes individualized at and below 500 °C, whereas the selenium analogue of bornite solid solution is present at all investigated temperatures, although with reduced extent on temperature decrease. The three iron selenides (β, γ, δ) display considerable solubility of copper, which for the mackinawite-like β FeSe reaches 14 at.% Cu at 300 °C. FeSe2 displays an immiscibility gap with isotropic solid solution (Cu,Fe)Se2, the composition of which gradually changes towards Cu-rich with decreasing temperature. Similarities and differences with the sulfur-based system are highlighted.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"203-221"},"PeriodicalIF":0.9,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900071","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45493330","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":"Warwickite from St. Lawrence County, New York: Mineral association, chemical composition, cation ordering, and splitting of the warwickite M1 site","authors":"M. Lupulescu, Alix M. Ehlers, J. Hughes, D. G. Bailey","doi":"10.3749/canmin.1900046","DOIUrl":"https://doi.org/10.3749/canmin.1900046","url":null,"abstract":"Warwickite has been discovered in the Edwards and Balmat #3 mines in the Balmat-Edwards mining district, St. Lawrence County, New York, located in the Adirondack Lowlands. The samples from the two mines are similar in chemistry and atomic arrangement but differ chemically from previously described samples; they are among the most Fe-poor samples described to date. The warwickite in the Edwards Mine sample occurs as 1–2 mm-diameter green crystals associated with pink spinel, forsterite, phlogopite, and pyrite in an impure dolomitic marble, whereas warwickite in the specimens from the Balmat #3 mine, approximately 10 km distant, occurs as brown to amber colored, slender, elongate, millimeter-size crystals in a calcitic marble in association with pink spinel, phlogopite, anhydrite, pyrite, and galena. Chemical analyses of the two specimens by electron microprobe show similar empirical formulas of (Mg1.43Ti0.36Al0.18Cr3+0.02Zr0.01)Σ2.00B0.98O4 (Edwards Mine) and (Mg1.39Ti0.40Al0.18Cr3+0.01Zr0.01Fe2+0.01)Σ2.00B0.94O4 (Balmat mine). The atomic arrangement of a specimen from each mine was determined, and the high-precision refinements provide new insight into the warwickite structure. The M1 site in warwickite is split into two sites to accommodate two occupants with differing bonding requirements; the M1 site contains Mg and the M1′ site hosts Ti, with the two sites being separated by approximately 0.2 Å. The optimized structural formula for both warwickite samples is similar to [M1(Mg0.84Al0.14Ti0.024+)2.74M1′(Ti0.914+Mn0.082+Mg0.01)1.30]Σ4.04M2(Mg0.86Al0.10Ti0.044+)4.00B4O16], demonstrating ordering of Mg at M1 and M2 and Ti at M1′. The site-splitting demonstrates how divalent Mg and tetravalent Ti can exist at a site in solid solution by ordering the two cations at split sites.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"183-190"},"PeriodicalIF":0.9,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44074237","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 the Athabasca Basin, Saskatchewan, Canada, and the Unconformity-related Uranium Deposits Hosted By It","authors":"P. Alexandre","doi":"10.3749/canmin.1900002","DOIUrl":"https://doi.org/10.3749/canmin.1900002","url":null,"abstract":"\u0000 A large data set comprising near-total digestion analyses of whole rock samples from the Athabasca Basin, Saskatchewan, Canada (based principally on the Geological Survey of Canada open file 7495), containing more than 20,000 analyses, was used to define the average chemical composition of Athabasca Group sandstones and of unconformity-related uranium deposits hosted by the basin.\u0000 The chemical composition of unaltered and un-mineralized Athabasca Group sandstones is dominated by Al (median Al2O3 of 1.14 wt.%), Fe (median Fe2O3 of 0.24 wt.%), and K (median K2O of 0.11 wt.%; Si was not measured), corresponding mostly to the presence of kaolin, illite, and hematite, in addition to the most-abundant quartz. The median concentration of U in the barren sandstones is 1 ppm, with 5 ppm Th, 3 ppm Pb, and 56 ppm ΣREE. Other trace elements present in significant amounts are Zr (median of 100 ppm), Sr (median of 69 ppm), and B (median of 43 ppm), corresponding to the presence of zircon, illite, and dravite.\u0000 The elements most enriched in a typical Athabasca Basin unconformity-related uranium deposit relative to the barren sandstone are U (median enrichment of ×710), Bi (×175), V (×77), and Mg (×45), followed by five elements with enrichment factors between 20 and 30 (Co, Mo, K, As, and Ni). These correspond to the presence in the ore bodies of alteration minerals (dravite, kaolinite, illite, chlorite, aluminum-phosphate-sulfate minerals, and a suite of sulfide minerals) and are similar to what has been observed before. These elements are similar to the typical pathfinder elements described above known deposits, but their usefulness has to be assessed based on their relative mobility in the predominantly oxidizing Athabasca Basin sandstones.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2020-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44417948","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":"Formation process of sub-micrometer-sized metasomatic platinum-group element-bearing sulfides in a Tahitian harzburgite xenolith","authors":"N. Akizawa, T. Kogiso, A. Miyake, A. Tsuchiyama, Y. Igami, M. Uesugi","doi":"10.3749/canmin.1800082","DOIUrl":"https://doi.org/10.3749/canmin.1800082","url":null,"abstract":"\u0000 Base-metal sulfides (BMSs) are minerals that host platinum-group elements (PGE) in mantle peridotites and significantly control the bulk PGE content. They have been investigated in detail down to the sub-micrometer scale to elucidate PGE behavior in the Earth's interior. Base-metal sulfides are supposedly subjected to supergene and seawater weathering, leading to the redistribution of PGEs at low temperatures. Careful and thorough measurements of BMSs are thus required to elucidate PGE behavior in the Earth's interior.\u0000 In the present study, a sub-micrometer-sized PGE-bearing sulfide inclusion in a clinopyroxene crystal in a harzburgite xenolith from Tahiti (Society Islands, French Polynesia) was investigated in detail (down to the sub-micrometer scale) using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDS). The sulfide inclusion is of carbonatitic metasomatic origin, as it is enveloped by carbonaceous glass, and forms a planar inclusion array with other PGE-bearing sulfide inclusions. The following sulfide phases were identified using TEM-EDS: Fe- and Ni-rich monosulfide solid solutions (MSSs), Fe- and Ni-rich pentlandite, sugakiite, heazlewoodite, chalcopyrite, and Cu-Ir-Pt-Rh-thiospinel (cuproiridsite–malanite–cuprorhodsite). We established the formation process of the metasomatic PGE-bearing sulfide inclusion by considering morphological and mineral characteristics in addition to the chemical composition. A primary MSS first crystallized from metasomatic sulfide melt at ca. 1000 °C, followed by the crystallization of an intermediate solid solution (ISS) below 900 °C. A high-form (high-temperature origin) Fe-rich pentlandite simultaneously crystallized with the primary MSS below ca. 850 °C and recrystallized into a low-form (low-temperature origin) Fe-rich pentlandite below ca. 600 °C. The primary MSS decomposed to Fe- and Ni-rich MSSs, low-form Ni-rich pentlandite, sugakiite, and heazlewoodite. The ISS decomposed to chalcopyrite below ca. 600 °C. Meanwhile, a Cu-Ir-Pt-Rh-thiospinel crystallized directly from the evolved Cu-rich sulfide melt below ca. 760 °C. Thus, Ir, Pt, and Rh preferentially partitioned into the melt phase during the crystallization process of the metasomatic sulfide melt. Metasomatic sulfide melts could be a significant medium for the transport and condensation of Pt together with Ir and Rh during the fractionation process in the Earth's interior. We hypothesize that the compositional variability of PGEs in carbonatites is due to the separation of sulfide melt leading to the loss of PGEs in the carbonatitic melts.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"99-114"},"PeriodicalIF":0.9,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1800082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48741260","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":"Electron microprobe study of turquoise-group solid solutions in the Neyshabour and Meydook mines, northeast and southern Iran","authors":"Elahe Mansouri Gandomani, N. Rashidnejad‐Omran, Amir Emamjomeh, P. Vignola, Tahereh Hashemzadeh","doi":"10.3749/canmin.1900004","DOIUrl":"https://doi.org/10.3749/canmin.1900004","url":null,"abstract":"\u0000 Turquoise, CuAl6(PO4)4(OH)8·4H2O, belongs to the turquoise group, which consists of turquoise, chalcosiderite, aheylite, faustite, planerite, and UM1981-32-PO:FeH. In order to study turquoise-group solid solutions in samples from the Neyshabour and Meydook mines, 17 samples were selected and investigated using electron probe microanalysis. In addition, their major elements were compared in order to evaluate the feasibility of distinguishing the provenance of Persian turquoises. The electron microprobe data show that the studied samples are not constituted of pure turquoise (or any other pure endmember) and belong, from the chemical point of view, to turquoise-group solid solutions.\u0000 In a turquoise–planerite–chalcosiderite–unknown mineral quaternary solid solution diagram, the chemical compositions of the analyzed samples lie along the turquoise–planerite line with minor involvement of chalcosiderite and the unknown mineral. Among light blue samples with varying hues and saturations from both studied areas, planerite is more abundant among samples from Meydook compared with samples from Neyshabour. Nevertheless, not all the light blue samples are planerite. This study demonstrates that distinguishing the deposit of origin for isochromatic blue and green turquoises, based on electron probe microanalysis method and constitutive major elements, is not possible.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"71-83"},"PeriodicalIF":0.9,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49507683","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":"Stability of sodalite relative to nepheline in NaCl–H2O brines at 750 °C: Implications for hydrothermal formation of sodalite","authors":"J. Schneider, D. Jenkins","doi":"10.3749/canmin.1900031","DOIUrl":"https://doi.org/10.3749/canmin.1900031","url":null,"abstract":"\u0000 Formation of the feldspathoid sodalite (Na6Al6Si6O24·2NaCl) by reaction of nepheline (NaAlSiO4) with NaCl-bearing brines was investigated at 3 and 6 kbar and at a constant temperature of 750 °C to determine the brine concentration at which sodalite forms with variation in pressure. The reaction boundary was located by reaction-reversal experiments in the system NaAlSiO4–NaCl–H2O at a brine concentration of 0.16 ± 0.08 XNaCl [= molar ratio NaCl/(NaCl + H2O)] at 3 kbar and at a brine concentration of 0.35 ± 0.03 XNaCl at 6 kbar. Characterization of the sodalite using both X-ray diffraction and infrared spectroscopy after treatment in these brines indicated no obvious evidence of water or hydroxyl incorporation into the cage structure of sodalite. The data from this study were combined with earlier results by Wellman (1970) and Sharp et al. (1989) at lower (1–1.5 kbar) and higher (7–8 kbar) pressures, respectively, on sodalite formation from nepheline and NaCl which models as a concave-down curve in XNaCl – P space. In general, sodalite buffers the concentration of neutral aqueous NaCl° in the brine to relatively low values at P < 4 kbar, but NaCl° increases rapidly at higher pressures. Thermochemical modeling of these data was done to determine the activity of the aqueous NaCl° relative to a 1 molal (m) standard state, demonstrating very low activities (<0.2 m, or 1.2 wt.%) of NaCl° at 3 kbar and lower, but rising to relatively high activities (>20 m, or 54 wt.%) of NaCl° at 6 kbar or higher. The results from this study place constraints on the concentration of NaCl° in brines coexisting with nepheline and sodalite and, because of the relative insensitivity of this reaction to temperature, can provide a convenient geobarometer for those localities where the fluid compositions that formed nepheline and sodalite can be determined independently.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"3-18"},"PeriodicalIF":0.9,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46446033","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":"Okieite, Mg3[V10O28]·28H2O, a new decavanadate mineral from the Burro mine, Slick Rock mining district, San Miguel County, Colorado, USA","authors":"A. Kampf, P. Adams, B. Nash, J. Marty, J. Hughes","doi":"10.3749/canmin.1900051","DOIUrl":"https://doi.org/10.3749/canmin.1900051","url":null,"abstract":"\u0000 Okieite, Mg3[V10O28]·28H2O, is a new decavanadate mineral from the Burro mine, Slick Rock district, San Miguel County, Colorado, USA (type locality); the mineral is also found at the Hummer mine, Paradox Valley, Montrose County, also in Colorado. The mineral is rare; it occurs with dickthomssenite on montroseite- and corvusite-bearing sandstone. Crystals of okieite from the Burro mine are equant to prismatic, commonly appearing like curving columns (up to about 3 mm in length) and often exhibiting rounded faces. The streak of okieite is light orange yellow, and the luster is vitreous. The Mohs hardness is ca. 1½, the tenacity is brittle, the fracture is curved or conchoidal, there is no cleavage, and the measured density is 2.20(2) g/cm3. Okieite is biaxial (–), with α = 1.720(3), β = 1.745(3), γ = 1.765(3) (white light); 2V = 84(2)° with strong r < v dispersion. The optical orientation is X ^ a = 37°, Y ^ c = 28°, Z ^ b = 31°. No pleochroism is observed in okieite. The empirical formula from electron-probe microanalysis (calculated on the basis of V = 10 and O = 56 apfu as indicated by the structure) is Mg2.86[H0.28V5+10O28]·28H2O. Okieite is triclinic, , with a 10.55660(19), b 10.7566(2), c 21.3555(15)Å, α 90.015(6), β 97.795(7), γ 104.337(7)°, and V 2326.30(19)Å3, as determined by single-crystal X-ray diffractometry. The strongest four diffraction lines in the powder diffractograms are [d in Å(I)(hkl)]: 9.71(100); 8.32(19); 11.04(17)(002); and 6.42(12)(110, . The atomic arrangement of okieite [R1 = 0.0352 for 11,327 I > 2σI reflections] consists of a {V10O28}6– (decavanadate) structural unit and a {[Mg(H2O)6]3·10H2O}6+ interstitial complex. Only hydrogen bonding links the structural unit with the components of the interstitial complex. Okieite is isostructural with synthetic Mg3[V10O28]·28H2O. The name okieite is for Craig (“Okie”) Howell of Naturita, Colorado.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"125-135"},"PeriodicalIF":0.9,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45224484","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":"Lumsdenite, NaCa3Mg2(As3+V4+2V5+10As5+6O51)·45H2O, a new polyoxometalate mineral from the Packrat mine, Mesa County, Colorado, USA","authors":"A. Kampf, J. Hughes, B. Nash, J. Marty, T. Rose","doi":"10.3749/canmin.1900061","DOIUrl":"https://doi.org/10.3749/canmin.1900061","url":null,"abstract":"\u0000 Lumsdenite (IMA 2018–092), ideally NaCa3Mg2(As3+V4+2V5+10As5+6O51)·45H2O, is a rare new polyoxometalate mineral from the Packrat mine, Gateway district, Mesa County, Colorado, USA. Crystals of lumsdenite occur as blades up to 0.2 mm in length, commonly growing in sprays. The crystals are dark green blue, with a green-blue streak. The mineral occurs on asphaltum, associated with montroseite- and corvusite-bearing sandstone. Other secondary minerals found in close association with lumsdenite are gypsum, huemulite, rösslerite, and at least two other potentially new minerals. Lumsdenite is optically biaxial (–), with α 1.617(2), β 1.651(5), and γ 1.675(5) in white light. The pleochroism scheme for lumsdenite is X = greenish yellow, Y = dark greenish blue, Z = greenish blue; X << Z < Y. The mineral is triclinic, , with a 10.3490(5), b 17.6263(9), c 23.2556(16) Å, α 82.208(6), β 88.351(6), γ 81.702(6)°, V 4158.8(4) Å3, and Z = 2. The strongest four powder diffraction lines for lumsdenite are [dobs Å(I)(hkl)]: , 14.86(80)(011), 17.30(44)(010), and 10.22(32)(100). The atomic arrangement of lumsdenite contains the novel polyoxometalate heteropolyanion [As3+V4+,5+12As5+6O51] structural unit in lumsdenite, [As3+V4+25+10As5+6O51]11−, which has previously been found in four other minerals from the Packrat mine. The charge of the structural unit is balanced by the charge of the [NaCa3Mg2(H2O)31·14H2O]11+ interstitial complex. The name lumsdenite is for the location of the mine at the head of Lumsden Canyon.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"137-151"},"PeriodicalIF":0.9,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42054749","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":"The occurrence of iron silicides in a fulgurite: Implications for fulgurite genesis","authors":"C. Stefano, S. Hackney, A. Kampf","doi":"10.3749/canmin.1900019","DOIUrl":"https://doi.org/10.3749/canmin.1900019","url":null,"abstract":"\u0000 Rapidly formed eutectic textures are observed in Fe silicides in a fulgurite from Michigan. The 14 cm-diameter fulgurite was formed in sandy glacial till in 2014 near Houghton Lake, Michigan. Spherical droplets of iron silicides up to ∼200 μm in diameter were found in the natural glass. Back-scattered electron images of some droplets show a eutectic intergrowth texture of two iron silicides with individual crystals up to ∼1 μm in maximum dimension. X-ray diffraction study showed the specimens to be an intergrowth of naquite (FeSi) and linzhiite (FeSi2) or naquite and xifengite (Fe5Si3). Droplets also contain minor native silicon, Fe-Ti silicides, and/or other Ti- rich phases which were discovered during TEM observations. It is important to note that the lower-temperature phase luobusaite (Fe3Si7) was not observed in any droplets, indicating rapid quenching of the fulgurite, consistent with a natural origin during a lightning strike as opposed to an artificial origin, e.g., resulting from a downed power line.","PeriodicalId":9455,"journal":{"name":"Canadian Mineralogist","volume":"58 1","pages":"115-123"},"PeriodicalIF":0.9,"publicationDate":"2020-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3749/canmin.1900019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48612796","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}