Lawsonite eclogites and metasomatites of the Utarbaev Association of the Maksyutov complex

Research subject. This article presents mineralogical, petrological and geochemical studies of lawsonite eclogites and metasomatites of the Utarbayev Аssociation of the Maksyutov complex. The Utarbayev Association forms an independent unit in the Maksyutovsky complex accretion structure. This Association features a variety of lawsonite-bearing metasomatites that form zonal halos in the frame of block-like diopside-grossular bodies included in the antigorite-serpentinite melange. The Utarbayev Association differs from typical lawsonite-blue shale complexes of collisional oro genes by the absence of mineral parageneses of lawsonite-bearing rocks of blue amphibolites.Methods. A microprobe analysis of the mineral composition was performed using a Cameca SX-100 microanalyzer. The content of petrogenic, rare and rare-earth elements was determined by X-ray spectroscopy (CPM-18) and mass spectroscopy (ICP-MS, ELAN-90). Results. An indicator mine ral paragenesis (Grt + Omp + Lws + Di) ± (Coe-Qz + Ttn) that characterizes lawsonite eclogite was found. Omphacite (Jd38–44) and unchanged lawsonite (Н2O-OH – 11.8%, Ca/Al = 0.48–0.51 и Fe/Al = 0.01 0.02%) are represented as inclusions in grossular-almandine garnet (Alm39–46Grs41–51), coesite – as microinclusions in omphacite. Thermobarometry (Grt-Omp, Grt-Omp-Ph) showed the following formation conditions of lawsonite paragenesis: T = 495–622°C under P = 2.2–2.4 GPa. The age of crystallization of lawsonite eclogite was found to be Lower Paleozoic (471–444 Ma).Conclusions. The lawsonite eclogite of the Utarbayev Association is similar to the complexes of «cold» eclogites, which are formed under the conditions of a very low geothermal gradient and are rarely preserved when removed into the upper crust. The latest review published in the «Journal of Metamorphic Geology» (2014) mentions 19 sites, where lawsonite eclogites were discovered on the earth’s surface. Тhe HP-UHP lawsonitebearing Utarbayev Rock Association complements this list.

Download Full-text

Serpentines as the indicators of mesozoic peridotites metamorphic and geodynamic transformations in the Internal Ukrainian Carpathians

Geology Geography Ecology ◽

10.26565/2410-7360-2019-51-04 ◽

2019 ◽

Keyword(s):

Microprobe Analysis ◽

High Alumina ◽

X Ray Diffraction ◽

Subduction Channel ◽

Basic Composition ◽

X Ray ◽

Study Results ◽

Geochemical Studies ◽

Tectonic Movements ◽

Geodynamic Reconstructions

Formulation of the problem. Peridotites of ophiolite complexes,being the fragments of the oceanic upper mantle that have undergone several stages of partial melting, brought to the surface by tectonic movements, also have undergone metamorphic transformations almost immediately after its formation. Because of serpentinization, the mineral composition of the rocks became more complicated. The analysis of the final structure and composition of apoperidotites allows obtaining data for geodynamic reconstructions regarding the stage of their formation. Review of previous publications. It has been determined that serpentines are the most common secondary minerals of peridotites of the Uholskyi complex in the Ukrainian Carpathians, and the processes of serpentinization took place at a depth of 40–50 to 100 km (?) at T = 450–600 °C and P = 13–16 kbar (Stupka O., 2013). The study of serpentinites of the Main Ural Fault (Panas'yan L. et al., 2014) revealed that high alumina and high chromium serpentinites have ultrabasic protoliths formed in the mantle, and medium alumina and low chromium varieties – the protoliths of the basic composition which were born in the conditions of the crust. Based on the study of serpentinites in the orogenic Qinling belt (China), researchers (Wu K. et al., 2018) determined their mantle origin: magnetite-enriched antigorite serpentinites were formed as a result of the interaction of serpentinized apoperidotites of mantle protoliths with molten rock in the subduction channel. Purpose. We have investigated secondary serpentines in order to reconstruct the geodynamic conditions of the formation and transformations of the peridotites (Uholskyi complex), localized in the Marmarosh rocky zone in the Internal Ukrainian Carpathians, and are most widely spread in the interfluve of Velyka and Mala Uholka-rivers. Methods. The work is based on the results of geological observations of the Uholskyi complex rocks in natural outcrops, as well as petrographic, mineralogical (including X-ray diffraction, thermal and microprobe analysis), and geochemical studies. Results. The paper presents the study results of serpentinized apoperidotites of the ophiolite Uholskyi complex in the Internal Ukrainian Carpathians. Serpentinized apoperidotites (T2–K1?) form olistoliths in the Soimulska olistostrome-conglomerate strata of the Lower Cretaceous age. The investigated serpentines are the rock-forming minerals of lizardite and antigorite serpentinites. Lizardite serpentinites are characterized by lenticular-looped textures formed by α-lizardite and non-altered chrome-spinellids. Antigorite serpentinites, recognized by striped-shale textures, contain antigorite, β-lizardite and magnetite. Lizardite serpentinites are characteristic of the regressive metamorphism of the greenschist facies upper part, and antigorite serpentinites are a typical formation of the progressive metamorphism of the lower greenschist – upperlower epidote-amphibolite facies. Regressive metamorphism occurred under geodynamic conditions of spreading and the progressive ones – under subduction conditions between the terrains of Dacia and Tisza, which led to the closure of the Transylvanian-Mureş Paleocean. It has been concluded, that the protoliths of lizardite serpentinites were the primary mantle rocks of the ultrabasic (restitic) composition, and the protoliths of the antigorite serpentinites were the lithospheric rocks of the basic composition. Conclusions. The complex study of serpentinized apoperidotites of the Uholskyi complex makes it possible to reconstruct the metamorphic transformations of the primary mantle protoliths and to determine the stages of lithosphere formation within the fold-nappe structures. The obtained results can be used for prediction of serpentinite mineralization.

Download Full-text

Ardennite-bearing mineral association related to sulfide-free ores with chalcophile metals at Nežilovo, Pelagonian Massif, North Macedonia

European Journal of Mineralogy ◽

10.5194/ejm-33-433-2021 ◽

2021 ◽

Vol 33 (4) ◽

pp. 433-445

Author(s):

Marko Bermanec ◽

Nikita V. Chukanov ◽

Ivan Boev ◽

Božidar Darko Šturman ◽

Vladimir Zebec ◽

...

Keyword(s):

Single Crystal ◽

Microprobe Analysis ◽

Unit Cell ◽

X Ray Diffraction ◽

Mineral Association ◽

Unit Cell Parameters ◽

X Ray ◽

Cell Parameters ◽

Formation Conditions ◽

Pelagonian Massif

Abstract. Among numerous minerals determined at Nežilovo, Pelagonian Massif, North Macedonia, ardennite-(As) has been discovered in two different associations and studied by means of optical microscopy, electron microprobe analysis (EMPA), and single-crystal and powder X-ray diffraction methods. The refractive indices of ardennite-(As) from Nežilovo are α=1.537(2), β=1.579(1) and γ=1.741(1), where γ corresponds to the c direction. The optical axial angle is 2Vx=49(1)∘. EMPA of the investigated samples yields the following empirical formulae: [Mn3.272+Ca0.73]Σ4.00[Al4.18Mg1.24Fe0.29Mn0.193+Zn0.10]Σ6.00(Si4.73Al0.27)Σ5.00(As0.96Si0.03V0.01)Σ1.00O22 [OH5.36(H2O)0.64]Σ6.00 for ardennite-(As) and (K0.95Na0.04Ba0.02)Σ1.01(Al1.44Fe0.303+Mg0.20Mn0.03Ti0.02 Zn0.01)Σ2.00(Si3.21Al0.79O10) (OH1.97O0.03)Σ2.00 for the associated red mica. The unit cell parameters of ardennite-(As) determined by X-ray powder diffraction are a=8.757(2) Å, b=5.836(2) Å, c=18.578(2) Å and V=941.97 Å3. The unit cell parameters of ardennite-(As) were also determined by single-crystal X-ray diffraction and are a=8.760(1) Å, b=5.838(1) Å, c=18.582(2) Å and V=950.30 Å3. Regularities of isomorphism in ardennite-related minerals are discussed. The presence of ardennite-(As) in association with 2M1 and 3T phengite polytypes provides evidence for three separate stages of formation. Conditions at which ardennite-(As) crystallized have been estimated based on compositional features of associated micas.

Download Full-text

Fluorescence effects in quantitative microprobe analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134533 ◽

1990 ◽

Vol 48 (2) ◽

pp. 188-189

Author(s):

S.J.B. Reed

Keyword(s):

Microprobe Analysis ◽

Depth Distribution ◽

Exciting Radiation ◽

Primary Radiation ◽

List Type ◽

Type Number ◽

Computing Power ◽

X Ray ◽

Fluorescent Radiation

Characteristic fluorescenceThe theory of characteristic fluorescence corrections was first developed by Castaing. The same approach, with an improved expression for the relative primary x-ray intensities of the exciting and excited elements, was used by Reed, who also introduced some simplifications, which may be summarized as follows (with reference to K-K fluorescence, i.e. K radiation of element ‘B’ exciting K radiation of ‘A’):1.The exciting radiation is assumed to be monochromatic, consisting of the Kα line only (neglecting the Kβ line).2.Various parameters are lumped together in a single tabulated function J(A), which is assumed to be independent of B.3.For calculating the absorption of the emerging fluorescent radiation, the depth distribution of the primary radiation B is represented by a simple exponential.These approximations may no longer be justifiable given the much greater computing power now available. For example, the contribution of the Kβ line can easily be calculated separately.

Download Full-text

DETERMINATION OF NICKEL, ZINC AND COBALT IN ADVANCED MATERIALS BASED ON NixCo3–xO4 AND ZnxCo3–xO4 BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY (ICP-MS) AND X-RAY FLUORESCENCE

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2018-84-1-i-10-13 ◽

2018 ◽

Vol 84 (1) ◽

pp. 10-13 ◽

Cited By ~ 4

Author(s):

A. A. Krotova ◽

K. Ya. Prikhodko ◽

S. A. Vladimirova ◽

D. G. Filatova

Keyword(s):

Mass Spectrometry ◽

Inductively Coupled Plasma ◽

Advanced Materials ◽

X Ray ◽

Inductively Coupled ◽

Nickel Zinc ◽

Determination Of Nickel ◽

Icp Ms ◽

Plasma Mass Spectrometry

Download Full-text

Hingganite-(Nd), Nd2□Be2Si2O8(OH)2, a new gadolinite-supergroup mineral from Zagi Mountain, Pakistan

The Canadian Mineralogist ◽

10.3749/canmin.2000039 ◽

2020 ◽

Vol 58 (5) ◽

pp. 549-562

Author(s):

Anatoly V. Kasatkin ◽

Fabrizio Nestola ◽

Radek Škoda ◽

Nikita V. Chukanov ◽

Atali A. Agakhanov ◽

...

Keyword(s):

New Mineral ◽

Monoclinic Space Group ◽

X Ray Diffraction ◽

Average Chemical Composition ◽

X Ray ◽

Conchoidal Fracture ◽

Icp Ms ◽

Optical Axes ◽

Mohs Hardness ◽

Khyber Pakhtunkhwa Province

ABSTRACT Hingganite-(Nd), ideally Nd2□Be2Si2O8(OH)2, is a new gadolinite group, gadolinite supergroup mineral discovered at Zagi Mountain, near Kafoor Dheri, about 4 km S of Warsak and 30 km NW of Peshawar, Khyber Pakhtunkhwa Province, Pakistan. The new mineral forms zones measuring up to 1 × 1 mm2 in loose prismatic crystals up to 0.7 cm long, where it is intergrown with hingganite-(Y). Other associated minerals include aegirine, microcline, fergusonite-(Y), and zircon. Hingganite-(Nd) is dark greenish-brown, transparent, has vitreous luster and a white streak. It is brittle and has a conchoidal fracture. No cleavage or parting are observed. Mohs hardness is 5½–6. Dcalc. = 4.690 g/cm3. Hingganite-(Nd) is non-pleochroic, optically biaxial (+), α = 1.746(5), β = 1.766(5), γ = 1.792(6) (589 nm). 2Vmeas. = 80(7)°; 2Vcalc. = 84°. Dispersion of optical axes was not observed. The average chemical composition of hingganite-(Nd) is as follows (wt.%; electron microprobe, BeO, B2O3, and Lu2O3 content measured by LA-ICP-MS; H2O calculated by stoichiometry): BeO 9.64, CaO 0.45, MnO 0.10, FeO 3.03, B2O3 0.42, Y2O3 8.75, La2O3 1.63, Ce2O3 12.89, Pr2O3 3.09, Nd2O3 16.90, Sm2O3 5.97, Eu2O3 1.08, Gd2O3 5.15, Tb2O3 0.50, Dy2O3 2.50, Ho2O3 0.33, Er2O3 0.84, Tm2O3 0.10, Yb2O3 0.44, Lu2O3 0.04, ThO2 0.13, SiO2 23.55, H2O 2.72, total 100.25. The empirical formula calculated on the basis of 2 Si apfu is (Nd0.513Ce0.401Y0.395Sm0.175Gd0.145Pr0.096Dy0.068La0.051Ca0.041Eu0.031Er0.022Tb0.014Yb0.011Ho0.009Tm0.003Th0.003Lu0.001)Σ1.979(□0.778Fe2+0.215Mn0.007)Σ1.000(Be1.967B0.062)Σ2.029Si2O8.46(OH)1.54. Hingganite-(Nd) is monoclinic, space group P21/c with a = 4.77193(15), b = 7.6422(2), c = 9.9299(2) Å, β = 89.851(2)°, V = 362.123(14) Å3, and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.105 (95) (011), 4.959 (56) (002), 4.773 (100) (100), 3.462 (58) (102), 3.122 , 3.028 (61) (013), 2.864 (87) (121), 2.573 (89) (113). The crystal structure of hingganite-(Nd) was refined from single-crystal X-ray diffraction data to R = 0.034 for 2007 unique reflections with I > 2σ(I). The new mineral is named as an analogue of hingganite-(Y), hingganite-(Yb), and hingganite-(Ce), but with Nd dominant among the rare earth elements.

Download Full-text

Do selenium hyperaccumulators affect selenium speciation in neighboring plants and soil? An X-Ray Microprobe Analysis

International Journal of Phytoremediation ◽

10.1080/15226514.2014.987374 ◽

2015 ◽

Vol 17 (8) ◽

pp. 753-765 ◽

Cited By ~ 20

Author(s):

Ali F. El Mehdawi ◽

Stormy D. Lindblom ◽

Jennifer J. Cappa ◽

Sirine C. Fakra ◽

Elizabeth A. H. Pilon-Smits

Keyword(s):

Microprobe Analysis ◽

Selenium Speciation ◽

X Ray

Download Full-text

Coiraite, (Pb,Sn2+)12.5As3Fe2+Sn4+5 S28: a franckeite-type new mineral species from Jujuy Province, NW Argentina

Mineralogical Magazine ◽

10.1180/minmag.2008.072.5.1083 ◽

2008 ◽

Vol 72 (5) ◽

pp. 1083-1101 ◽

Cited By ~ 3

Author(s):

W. H. Paar ◽

Y. Moëlo ◽

N. N. Mozgova ◽

N. I. Organova ◽

C. J. Stanley ◽

...

Keyword(s):

Low Temperature ◽

Microprobe Analysis ◽

Electron Microprobe Analysis ◽

Mineral Species ◽

New Mineral ◽

Hydrothermal Solutions ◽

X Ray ◽

New Mineral Species ◽

Primary Mineral ◽

The Ideal

AbstractCoiraite, ideally (Pb,Sn2+)12.5As3Fe2+Sn4+S28, occurs as an economically important tin ore in the large Ag-Sn-Zn polymetallic Pirquitas deposit, Jujuy Province, NW-Argentina. The new mineral species is the As derivative of franckeite and belongs to the cylindrite group of complex Pb sulphosalts with incommensurate composite-layered structures. It is a primary mineral, frequently found in colloform textures, and formed from hydrothermal solutions at low temperature. Associated minerals are franckeite, cylindrite, pyrite-marcasite, as well as minor amounts of hocartite, Ag-rich rhodostannite. arsenopyrite and galena. Laminae of coiraite consist of extremely thin bent platy crystals up to 50 urn long. Electron microprobe analysis (n = 31) gave an empirical formula Pb11.21As2.99Ag0.13Fe1.10Sn6.13S28.0 close to the ideal formula (Pb11.3Sn2+1.2)Σ=12.5As3Fe2+Sn4+S28. Coiraite has two monoclinic sub-cells, Q (pseudotetragonal) and H (pseudohexagonal). Q: a 5.84(1) Å, b 5.86(1) Å, c 17.32(1) Å, β 94.14(1)°, F 590.05(3) Å3, Z = 4, a:b:c = 0.997:1:2.955; H (orthogonal setting): a 6.28(1) Å, b 3.66(1) Å, c 17.33(1) Å, β 91.46(1)°, V398.01(6) Å3, Z = 2, a∶b∶c = 1.716∶1∶4.735. The strongest Debye-Scherrer camera X-ray powder-diffraction lines [d in Å, (I), (hkl)] are: 5.78, (20), (Q and H 003); 4.34, (40), (Q 004); 3.46, (30), (Q and H 005); 3.339, (20), (Q 104); 2.876, (100), (Q and H 006); 2.068, (60), (Q 220).

Download Full-text