Carbonate enrichment at the margins of a basic dyke, Ardnamurcha

1974 ◽  
Vol 39 (305) ◽  
pp. 514-524 ◽  
Author(s):  
M. K. Wells ◽  
A. C. S. Smith ◽  
J. F. W. Bowles
Keyword(s):  
Mineral Content ◽  
Microprobe Analysis ◽  
The Other ◽  
Transient Effects ◽  
Basic Dyke ◽  
X Ray ◽  
Fine Grained ◽  
Titaniferous Magnetite ◽  
Oxide Phases ◽  
Opaque Minerals

SummaryA gradational increase in concentration of CO2 towards the margins of a very fine-grained basalt dyke has led to the development of a pale marginal facies, enriched in carbonates, particularly siderite. Increases in CO2 from about 3 % in the interior of the dyke to 8 % at the margins are accompanied by decreases in SiO2 and Fe2O3, increases in Al2O3, and less significant changes in the other major components. Cu, Co, and Zn change only slightly, and Cr, Ni, and Li remain constant. Petrographic variation is considerable, even in the superficially homogeneous interior of the dyke, in which it ranges from a type containing a titanaugite (analysed) to one devoid of pyroxene, but containing conspicuous opaque minerals. Microprobe analysis for Fe and Ti shows that these comprise: cotahedral titaniferous magnetite; rodlets, less than 1 µm thick, of rutile partly altered to, or overgrown by, ilmenite; and sub-opaque patches with a very low Ti/Fe ratio. Plagioclase, An55, is the most abundant and constant crystalline phase in the interior of the dyke, but changes to An20 in the marginal facies. Mineral-content of the latter, deduced from optical, chemical, and X-ray data, also includes siderite, serpentine and clay minerals, leucoxene, and apatite. There is no evidence of quartz, sericite, or calcite.Petrographic evidence shows that variations in concentrations of CO2 and H2O affected phase equilibria from the start of magmatic crystallization. Data on the fO2 required for TiO2 and Fe-oxide phases to co-exist at magmatic temperatures indicate that, initially, the concentrations of CO2 and H2O in the interior of the dyke were higher than the values recorded in analyses of the rocks. From this evidence and the field relationships, it is concluded that the intruding magma was rich in volatiles, which diffused towards the dyke margins and, in part, became trapped as the magma congealed, producing a changed marginal assemblage of minerals. The dyke provides a unique glimpse of influences on a basic magma exerted by what S. J. Shand has aptly termed the ‘fugitive constituents’, the transient effects of which are rarely preserved in the rocks.

Terracottas Around Clodion: Chemical and Mineralogical Studies and Thermoluminescence Analysis

1992 ◽  
Vol 267 ◽  
Author(s):  
Frédéric Saltron ◽  
Anne Bouquillon ◽  
Guirec Querré
Keyword(s):  
Microprobe Analysis ◽  
Ion Beam ◽  
The Other ◽  
X Ray ◽  
Thermoluminescence Analysis

ABSTRACTForty one terracottas by Clodion, Marin and P. Michel, all french sculptors of the XVIIIth century, have been analyzed in the L.R.M.F.Two different kinds of analysis have been performed.The results obtained by thermoluminescence allowed to partition the works between one group contemporaneous with the Clodion period and the other one consisting of posterior works. Although the lowest limit in the use of thermoluminescence seems to be reached, the conclusions are, more often than not, in agreement with the hypotheses of the curator.X-Ray diffractometry, microprobe analysis and ion-beam methods (PIXE) have led to distinguish between siliceous pastes corresponding to artifacts created in Paris and carbonated pastes gathering terracottas made during the italian stays of the artists.

scholarly journals Upper Cretaceous rhyolitic ashes in the Utes Derevyannykh Gor area (Novaya Sibir Island, the New Siberian Islands)

2019 ◽  
Vol 20 (1) ◽  
pp. 37-47
Author(s):  
V. V. Kostyleva ◽  
E. V. Shchepetova ◽  
A. E. Kotelnikov
Keyword(s):  
Upper Cretaceous ◽  
Microprobe Analysis ◽  
Clay Fraction ◽  
Field Work ◽  
Pyroclastic Material ◽  
New Siberian Islands ◽  
High Potassium ◽  
X Ray ◽  
Fine Grained ◽  
Scanning Electron

The article is concerned with the first finds of rhyolite ashes in Upper Cretaceous sediments of Novaya Sibir Island. In the course of the field work in the area of cape Utes Derevyannykh Gor in 2016, four layers of unlithified fine-grained ashes were found in the Turonian-Coniacian coal-bearing Derevyannye Gory Formation. The article presents the results of petrographic, X-ray diffractometric and microprobe analysis of pyroclastics from ash layers. A typification of volcanogenic-terrigenous deposits is proposed. Thin section of the samples were investigated on a polarizing microscope. X-ray phase analysis of the clay fraction was carried out using a DRON-3 diffractometer. X-ray microanalysis of vitroclasts were carried out on a scanning electron microscope “Jeol JSM-6480LV” with the microprobe analyzer “Oxford Instruments INCA-Energy 350”. It was established that Derevyannye Gory Formation is composed of rhyolitic tuffites, among which fine-grained crystal-vitroclastic and vitroclastic ashes of low and normal alkaline high-potassium rhyolites with thickness up to 2.5 m. Low pyroclastics sediments are not widespread. New data on the structure and composition of the Derevyannye Gory Formation confirm the hypothesis of previous researchers, that sedimentation in the Late Cretaceous in the area of Novaya Sibir Island was accompanied by explosive acidic volcanism. The main purpose of the article is to discuss the sources of pyroclastic material for the territory of the New Siberian Islands in the Turonian-Coniacian age. The conclusion is made about the territorial proximity of the paleovolcanic eruption center to the area of sedimentation. It is assumed that the paleovolcanic centers were located within the present territory of Kotelny, Zemlya Bunge, Faddeevsky islands and, probably, were inherited from the Early Albian stage.

On the relation of chamosite and daphnite to the chlorite group (With Plates XVIII and XIX.)

1939 ◽  
Vol 25 (167) ◽  
pp. 441-465 ◽  
Author(s):  
A. F. Hallimond
Keyword(s):  
Low Temperature ◽  
Simple Formula ◽  
British Museum ◽  
The Other ◽  
Geological Survey ◽  
Chemical Analyses ◽  
X Ray ◽  
Fine Grained ◽  
New Material ◽  
Crystalline Nature

There is a close optical and chemical resemblance between chamosite, the chloritic mineral of the bedded ironstones, and daphnite, a low-temperature vein-chlorite common in some of the Cornish tin mines. New material has made it possible to undertake a fresh comparison of the two minerals: chemical analyses have been made by Mr. C. O. Harvey, chemist to H.M. Geological Survey, and a report on the X-ray measurements is contributed by Mr. F. A. Bannister, of the Mineral Department of the British Museum.The new analysis of chamosite agrees with the simple formula previously assigned: X-ray examination of material from several localities has now established the distinctive crystalline nature of this fine-grained mineral, which differs structurally from ordinary chlorites such as clinochlore. Daphnite, on the other hand, has the ordinary chlorite structure, but the new analysis fully confirms Tschermak's original opinion that it cannot be represented chemically as a mixture of serpentine and amesite.

Vanadoallanite-(La): a new epidote-supergroup mineral from Ise, Mie Prefecture, Japan

2013 ◽  
Vol 77 (6) ◽  
pp. 2739-2752 ◽  
Author(s):  
M. Nagashima ◽  
D. Nishio-Hamane ◽  
N. Tomita ◽  
T. Minakawa ◽  
S. Inaba
Keyword(s):  
Microprobe Analysis ◽  
The Other ◽  
New Mineral ◽  
Transition Elements ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Octahedral Cations ◽  
Cation Distributions

AbstractThe new mineral, vanadoallanite-(La), found in the stratiform ferromanganese deposit from the Shobu area, Ise City, Mie Prefecture, Japan, was studied using electron microprobe analysis and single-crystal X-ray diffraction methods. Vanadoallanite-(La) is a rare-earth element-rich monoclinic epidote-supergroup mineral with simplified formula CaLaV3+AlFe2+(SiO4)(Si2O7)O(OH) (Z = 2, space group P21/m) characterized by predominantly V3+ at one of three octahedral sites, M1. The crystal studied shows large V (∼8.4 V2O3 wt.%), Fe (∼13.8 Fe2O3 wt.%; Fe2+/total Fe = 0.58) and Mn (∼8.8 MnO wt.%) contents. A small amount of Ti is also present (∼1.3 TiO2 wt.%). Structural refinement converged to R1 = 2.96%. The unit-cell parameters are a = 8.8985(2), b = 5.7650(1), c = 10.1185(2) Å, β = 114.120(1)° and V = 473.76(2) Å3. The cation distributions determined at A1,A2 and M3 are Ca0.61Mn0.39, (La0.46Ce0.14Pr0.07Nd0.18)Σ0.85Ca0.15 and Fe2+0.56Mn2+0.30Mg0.06V3+0.05Fe3+0.03, respectively. On the other hand, depending on Ti assignment, two different schemes of the cation distribution at M1 and M2 can be considered: (1) M1(V3+0.58Fe3+0.34Ti4+0.08) M2(Al0.92Fe3+0.08), and (2) M1(V3+0.58Fe3+0.42)M2(Al0.92Ti4+0.08). In both cases, the dominant cations at A1, A2, M1, M2 and M3 are Ca, La, V3+, Al and Fe2+ , respectively. According to ionic radius, Ti4+ possibly prefers M2 rather than Fe3+. A large Mn2+ content at A1 also characterizes our vanadoallanite-(La). The structural change of Mn2+-rich allanite-group minerals is considered to be controlled by two main factors. One is the large Mn2+ content at A1 in vanadoallanite-(La), which modifies the topology of the A1O9 polyhedron. The other is the expansion of M3O6 and M1O6 octahedra caused by large octahedral cations, such as Fe2+ and Mn2+, at M3 and the trivalent transition elements, V3+ and Fe3+, at M1.

Composition minérale des écailles du Catostomus commersoni issu de deux milieux différents: étude par microscopie électronique analytique

1974 ◽  
Vol 31 (1) ◽  
pp. 63-66 ◽  
Author(s):  
R. van Coillie ◽  
A. Rousseau
Keyword(s):  
Electron Microprobe ◽  
Mineral Content ◽  
The Other ◽  
Catostomus Commersoni ◽  
X Ray ◽  
Healthy Environment ◽  
Microscopie Électronique ◽  
Other Substances ◽  
The Difference ◽  
Polluted Waters

The mineral content of scales, metals only, was studied. Fish of the Catostomus commersoni subspecies were used, taken from a healthy environment, (the Manicouagan River) and an environment polluted by, among other substances, various metals (Rivière des Prairies, near Montréal). X-ray microspectrometry was combined with electron microprobe scanning techniques, with subsequent microdensitometric scanning. Scales contained, in addition to the highly predominant calcium, the following: Na, Mg, Al, K, Fe, Cu, Zn, and Ba, as well as some Cr, Mn, Co, Ni, Sr, Ag, Cd, Cs, Hg, and Pb. All metals were between the circuli in the osteoid structures. The latter category of metals, widely known for their toxicity, were more abundant in the scales of the sample from polluted waters, whereas the reverse was true for the other metals, with the exception of Al and Ba, which were found in equal quantities in both samples. If the difference in content of the scales taken from fish of the two different environments is seen in relation with the fact that the toxic metals are more abundant in polluted waters and the fact that there is the possibility that excess metal from the water can replace calcium in the scales, we may infer that the mineral content of scales is related at least in part to that of the surrounding aquatic environment.

Investigation of Natural and Artificial Zr-silicate Gels

2006 ◽  
Vol 932 ◽  
Author(s):  
Boris E. Burakov ◽  
Andrey Ph. Smetannikov ◽  
Evgeniy B. Anderson ◽  
Alexander Yu. Alexeev
Keyword(s):  
Electron Microscopy ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Chemical Durability ◽  
High Chemical ◽  
X Ray ◽  
Transmission Electron ◽  
Oxide Phases ◽  
Intermediate Storage

ABSTRACTSample of natural Zr-silicate gel containing up to 13 wt.% U was characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and electron microprobe analysis (EPMA) method. It was found that gel matrix is amorphous in general; however, it contains non-identified nanocrystallites. No separated oxide phases of U, Zr or Si were observed in a gel matrix. After sintering in air at 1400°C for 1 hour gel transformed largely into crystalline zircon, (Zr,U)SiO4. Uranium was not found in any other phases besides zircon. It was assumed that high chemical durability of natural Zr-P-U-Ti-silicate gel is caused by two competing processes which exist under self-irradiation conditions: 1) crystallization of the gel and 2) metamictization of the crystallized zircon and other phases.Synthetic samples of Zr-silicate gel doped with Ce, U, Pu and Am were obtained and studied in comparison with natural samples. It was suggested to use artificial solid Zr-silicate gels for durable fixation of actinides for the goal of long-term or intermediate storage.

scholarly journals The Upper Cretaceous intrusive rocks with extensive crustal contribution in Hacımahmutuşağı Area (Aksaray/Turkey)

2019 ◽  
Vol 70 (3) ◽  
pp. 261-276
Author(s):  
Serhat Köksal
Keyword(s):  
Mafic Magma ◽  
The Other ◽  
Granitic Rocks ◽  
Geochemical Data ◽  
Magma Source ◽  
Accessory Zircon ◽  
Fine Grained ◽  
Intrusive Rocks ◽  
Crustal Contribution ◽  
Opaque Minerals

Abstract The Hacımahmutuşağı area (Aksaray/Turkey) is located in the western part of the Central Anatolian Crystalline Complex (CACC). Gneiss and marble compose the basement units, while intrusive rocks are gabbros and granitoids. The pegmatitic hornblende gabbros contain pegmatitic to fine-grained hornblendes, plagioclase, clinopyroxene, and accessory opaque minerals. The fine-grained gabbros, on the other hand, are composed of plagioclase, hornblende, and biotite as major components whereas the apatite and opaque minerals are present in accessory content. Granitic– granodioritic rocks are the common intrusive rock types in the area, and constitute quartz, orthoclase, plagioclase and biotite, and accessory zircon and opaque minerals. Leucogranites, comprising quartz, orthoclase, plagioclase with minor biotite, hornblende, and with accessory apatite and opaque minerals, are found as dykes intruding the marble and the granitic–granodioritic rocks. Strontium–neodymium isotope data of gabbros and granitoids have high 87Sr/86Sr(i) ratios (0.7076 to 0.7117) and low ɛNd(i) values (−5.0 to −9.8) point out enriched source and pronounced crustal contribution in their genesis. In the Hacımahmutuşağı area, it is plausible that the heat increase caused by the hot zone, which was generated by underplating mafic magma along with the hydrous mafic sills in the lower crust, might have resulted in partial melts from crystallized mafic sills and older crustal rocks. It can be suggested that these hybrid melts adiabatically rose to the shallow crust, ponded and crystallized there and formed the magma source of the intrusive rocks within the Hacımahmutuşağı area and the other hybrid granitic rocks with crustal signatures in the CACC. Geochemical data indicate that granitoids and gabbros are collision to post-collision related sub-alkaline rocks derived from an enriched source with extensive crustal inputs.

Microchemical imaging in biomedical research

1992 ◽  
Vol 50 (2) ◽  
pp. 1118-1119
Author(s):  
P. Ingram
Keyword(s):  
Data Analysis ◽  
Electron Probe ◽  
The Other ◽  
X Ray ◽  
Cell Element ◽  
Physiological Information ◽  
Functional States ◽  
Elemental Maps ◽  
Electron Energy Loss ◽  
Secondary Ion

It is well established that unique physiological information can be obtained by rapidly freezing cells in various functional states and analyzing the cell element content and distribution by electron probe x-ray microanalysis. (The other techniques of microanalysis that are amenable to imaging, such as electron energy loss spectroscopy, secondary ion mass spectroscopy, particle induced x-ray emission etc., are not addressed in this tutorial.) However, the usual processes of data acquisition are labor intensive and lengthy, requiring that x-ray counts be collected from individually selected regions of each cell in question and that data analysis be performed subsequent to data collection. A judicious combination of quantitative elemental maps and static raster probes adds not only an additional overall perception of what is occurring during a particular biological manipulation or event, but substantially increases data productivity. Recent advances in microcomputer instrumentation and software have made readily feasible the acquisition and processing of digital quantitative x-ray maps of one to several cells.

Fluorescence effects in quantitative microprobe analysis

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.

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