Mineralogy and petrography of the Keban Pb-Zn-(Cu) skarn deposit, Elaziğ, eastern Turkey

2020 ◽  
Author(s):  
Ece Kirat ◽  
Halim Mutlu
Keyword(s):  
Raman Spectroscopy ◽  
Contact Zone ◽  
Coarse Grained ◽  
Alteration Zone ◽  
Skarn Deposit ◽  
Temperature Conditions ◽  
Salt Minerals ◽  
Skarn Deposits ◽  
Plutonic Rocks ◽  
Syenite Porphyry

<p>The Keban Pb-Zn-(Cu) skarn deposit in the Elazığ region, Turkey, was formed at the contact zone of the Permo-Triassic metamorphics and the Late Cretaceous plutonic rocks in the Eastern Taurus orogenic belt. The mineralization is hosted by skarn and meta-clastic/carbonate rocks of the Keban Metamorphics intruded by alkali syenite porphyry, which is associated with the Pb-Zn-(Cu) mineralization. The rock units in the region are partly hydrothermally altered graphite calc-schist containing crystallized limestone interlayers and lenses, meta-pellitic rocks (phylitte/calc-phyllite), dolomitic limestone, calc-silicate hornfels, marble and plutonic rocks. Calc-silicate hornfels is an initial metamorphic product occurred in contact zone of the intrusive unit. Results of mineralogical studies indicate that garnet and pyroxene-rich skarn formed in early (prograde) stage of skarnization whereas epidote, chlorite, tremolite, phlogopite, muscovite, calcite, quartz and fluorite are typical minerals of the retrograde stage. Using the Raman spectroscopy investigations, garnets in alteration zone are subdivided into two groups. Garnets in andradite composition are zoned and occur close to the intrusion reflecting high-temperature conditions and those of grossular composition represent low-temperature conditions. The sill/dykes and stock-like Keban plutonic rocks hosting foid syenite porphyry and nepheline syenite are of holocrystalline hipidiomorph porphyritic texture including large nepheline and plagioclase phenocrysts. Metallic minerals comprise sphalerite, galena, chalcopyrite, magnetite, bornite, pyrite, fahlore and hematite, which mainly occur as dissemination, vein and massive forms and crosscut by late-stage quartz, fluorite and calcite veinlets. Sphalerite is medium-coarse grained, semi-euhedral and contain chalcopyrite inclusions. Blebs of chalcopyrite are widely recognized in sphalerite (chalcopyrite disease). Galena replaces sphalerite and in some cases, it hosts several sulfo-salt minerals. Magnetite partly or completely transforms to limonite and chalcopyrite inclusions in sphalerite occur among the magnetite grains.</p><p><strong>Key words: </strong>Keban, Pb-Zn-(Cu) skarn deposits, Mineralogy, Petrography, Ore Microscopy, Raman Spectroscopy</p>

Raman spectroscopy of captopril crystals under low-temperature conditions

2020 ◽  
Vol 243 ◽  
pp. 118734
Author(s):  
D.L.M. Vasconcelos ◽  
F.F. de Sousa ◽  
J.G. da Silva Filho ◽  
A.M.R. Teixeira ◽  
P.F. Façanha Filho ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Low Temperature ◽  
Temperature Conditions

scholarly journals Iron Isotopes Constrain the Metal Sources of Skarn Deposits: A Case Study from the Han-Xing Fe Deposit, China

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 951
Author(s):  
Bin Zhu ◽  
Hongfu Zhang ◽  
M. Santosh ◽  
Benxun Su ◽  
Pengfei Zhang ◽  
...  
Keyword(s):  
Major Elements ◽  
Ore Deposits ◽  
Magmatic Fluid ◽  
Skarn Deposit ◽  
Mass Balance Calculation ◽  
Positive Correlation ◽  
Fe Isotopes ◽  
Magmatic Fluids ◽  
Skarn Deposits

Magmatic fluids and leaching of rocks are regarded as the two sources of magmatic hydrothermal deposits, but their relative contributions to the metals in the deposits are still unclear. In this study, we combine major elements and Fe isotopes in two sets of rocks from the Han-Xing iron skarn deposit in China to constrain the iron sources. The positive correlation between the δ56Fe and ∑Fe2O3/TiO2 of altered diorites (∑Fe2O3 refers to the total iron) demonstrates that heavy Fe isotopes are preferentially leached from diorites during hydrothermal alteration. However, except for the pyrite, all the rocks and minerals formed in the skarn deposit are enriched in the light Fe isotope relative to the fresh/less altered diorites. Therefore, besides the leaching of rocks, the Fe isotopically light magmatic fluid also provides a large quantity of iron for this deposit. Based on the mass balance calculation, we conclude that iron from magmatic fluid is almost 2.6 times as large as that from the leaching of rocks. This is the first study to estimate the relative proportions of iron sources for Fe deposits by using Fe isotopes. Here, we propose that the high δ56Fe of magmatic intrusions combining the positive correlation between their ∑Fe2O3/TiO2 and δ56Fe could be taken as a fingerprint of exsolution or interaction with magmatic fluids, which contributes to the exploration of magmatic hydrothermal ore deposits.

scholarly journals Crack-enhanced weathering in inscribed marble: a possible application in epigraphy

2021 ◽  
Vol 33 (2) ◽  
pp. 189-202
Author(s):  
Stylianos Aspiotis ◽  
Jochen Schlüter ◽  
Kaja Harter-Uibopuu ◽  
Boriana Mihailova
Keyword(s):  
Raman Spectroscopy ◽  
Penetration Depth ◽  
Environmental Conditions ◽  
Coarse Grained ◽  
Asia Minor ◽  
X Ray Diffraction ◽  
Western Turkey ◽  
Fine Grained ◽  
Rock Types ◽  
Micro Cracks

Abstract. Raman spectroscopy has been applied to check if there are detectible material differences beneath the inscribed and non-inscribed areas of marble-based written artefacts, which could be further used to visualize lost or hardly readable text via suitable mapping. As a case study, marble segments with ∼ 2000-year-old inscribed letters from Asia Minor (western Turkey) and marble gravestones with 66 ± 14-year-old inscriptions from the cemetery of Ohlsdorf (Hamburg, Germany) have been subjected to Raman spectroscopy, as well as to complementary X-ray diffraction, wavelength-dispersive electron probe microanalysis, and Fourier-transform infrared spectroscopy, to thoroughly study the effect of different environmental conditions, grain size, and inscription age on the nature and penetration depth of marble alteration. The results demonstrate that environmental conditions rule over the type of dominant weathering changes, which are carotenoid molecular inclusions produced by lichen and amorphous carbon for marbles from Hamburg and Asia Minor, respectively. The alteration is much stronger in medium- and coarse-grained than in fine-grained marble, but it is suppressed by letter colouring. In the absence of letter colouring, the weathering-related products in both ancient and modern engraved marbles are more abundant beneath than away from the engraved areas, and the penetration depth is larger due to the enhancement of fissures and micro-cracks around the inscribed areas. We show that the Raman intensity ratio between the strongest peak of the weathering-related product (ν(C=C) ∼ 1520 cm−1 for carotenoids or the G peak ∼ 1595 cm−1 for soot-like carbon) and the strongest peak of marble (CO3 stretching near 1087 cm−1) can serve as a quantitative marker to indirectly map the lateral distribution of cracks induced during the inscribing process and hence can potentially be used to trace lost text on vanished marble inscriptions. This approach can be applied to other rock types, but further studies are required to identify the corresponding autochthonous weathering-related products.

Experimental investigation of microbially induced carbonate precipitation in sandstone cores under in-situ North Sea temperature and pressure conditions

2020 ◽  
Author(s):  
Fabian Steinacher ◽  
Dr Arianna G. Pagano ◽  
Dr Gráinne El Mountassir ◽  
Dr James M. Minto ◽  
Prof Rebecca J. Lunn
Keyword(s):  
North Sea ◽  
Exposure Time ◽  
Oil And Gas ◽  
Coarse Grained ◽  
Carbonate Precipitation ◽  
Temperature Conditions ◽  
Microbially Induced Carbonate Precipitation ◽  
Temperature And Pressure ◽  
Subsurface Temperatures

<p>Bio-grouting using ureolytic microorganisms has been developed over the past decade for civil engineering applications including: (i) sealing fractures in rock, (ii) sealing cracks in cement, (iii) reducing the permeability of porous media  and (iv) soil stabilisation and (v) repair of concrete and stone. This study investigates the potential application of microbially induced carbonate precipitation (MICP) within the oil and gas industry. To deploy MICP in a well abandonment context a more in-depth knowledge of the influence and performance under elevated subsurface pressures and temperatures is required.</p><p>Batch experiments investigated the ureolytic activity at subsurface temperatures ranging from 20-90°C and fluid pressures from 1-13MPa for up to 2hrs exposure time. Strong evidence of increased ureolytic activity was observed in specimens at temperatures of 60°C and above, but with increasing exposure time ureolytic activity ceased. In comparison increased fluid pressures had little influence on ureolytic activity. Our results imply that the bacterial cell protects the enzyme from denaturation at elevated temperature conditions.</p><p>A second set of experiments consisted of multiple injections of the treatment fluids in a fine-grained sandstone sampled from the Brent sandstone formation of the Dunlin oilfield in the North Sea. With a focus on simulating the in-situ environmental conditions, we set-up a high pressure high temperature system consisting of a HPLC pump, water bath, Hassler core-holder with pressure capabilities of up to 2400psi and a temperature rating of 90°C with high sensitivity pressure transducers and a backpressure regulator. The cores were exposed to realistic North Sea subsurface temperatures of 20, 50, 60°C and fluid pressures of 442, 1326, 1621psi according to their corresponding depths: at 1000ft, 3000ft and 3667ft.</p><p>The study investigated the influence of the pressure and temperature conditions on (i) permeability reduction, (ii) distribution of CaCO<sub>3</sub> precipitates via X-CT imaging and (iii) mineralogy via FE-EPMA coupled with EDX/WDX spectroscopy.</p><p>Permeability reductions in the coarse-grained sandstones of 5 orders of magnitude were achieved in all the subsurface temperature-pressure combinations tests. Micro xCT scans indicate that CaCO<sub>3</sub> precipitation occurred closer to the inlet as the temperature and pressure increased, due in part to the higher ureolytic activity at higher temperatures and the lower solubility of CaCO<sub>3</sub> at higher temperatures. At elevated pressure and temperature conditions the energy barrier to transform from a calcite dominated system could be overcome and formed predominantly aragonite.</p><p>This study has demonstrated the potential for deploying MICP at subsurface conditions in oil and gas applications. The biotechnology itself could be used to seal off reservoir formations in mature oil and gas assets, repair fluid migration pathways or act as an environmental wellbore barrier element and therefore could ultimately reduce the number of well barriers required to be installed during plugging and abandonment.</p>

scholarly journals Alpine metamorphism in the central segment of the Western Greywacke Zone (Eastern Alps)

2009 ◽  
Vol 60 (4) ◽  
pp. 319-329 ◽  
Author(s):  
Gerd Rantitsch ◽  
Katalin Judik
Keyword(s):  
Raman Spectroscopy ◽  
Organic Matter ◽  
Heat Transport ◽  
Contact Zone ◽  
Eastern Alps ◽  
Tauern Window ◽  
Central Segment ◽  
Alpine Metamorphism ◽  
Maximum Temperatures ◽  
Advective Heat Transport

Alpine metamorphism in the central segment of the Western Greywacke Zone (Eastern Alps)The metamorphic pattern of the central Western Greywacke Zone (Austroalpine, Eastern Alps) was investigated by organic matter reflectance, Raman spectroscopy on organic matter and clay mineralogical methods. Raman data map a 10 km wide thermal aureole along the contact zone of the Greywacke Zone to the Penninic Tauern Window. The estimated maximum temperatures of 400 °C to 200 °C decrease from South to North, that is from the contact to the uppermost parts of the Greywacke Zone. This pattern is explained by an Oligocene to Miocene thermal pulse, related to the rapid exhumation of formerly deeply buried rocks of the Penninic unit. During this event, advective heat transport and circulating fluids overprinted the Cretaceous higher anchi- to lower epizonal metamorphic pattern of the central Western Greywacke Zone.

scholarly journals Relaxor ferroelectrics materials under high pressure

2014 ◽  
Vol 70 (a1) ◽  
pp. C979-C979
Author(s):  
Arthur Haozhe Liu ◽  
Lisa Luhong Wang ◽  
Lingping Kong
Keyword(s):  
Phase Diagram ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
High Temperature ◽  
Relaxor Ferroelectrics ◽  
Ferroelectric Materials ◽  
Structure Evolution ◽  
Cubic Phase ◽  
Temperature Phase ◽  
Temperature Conditions

The rich phase diagrams from both relaxor and normal ferroelectrics under high pressure, stimulate us to study the pressure effect on the relaxor-PbTiO3 (PT) systems, to check whether the high pressure cubic structure will turn to low symmetry structure upon strong compression is the common behaviors for relaxor ferroelectrics materials. Furthermore, a complete phase diagram study of pressure-temperature effect on structure will allow us to explore the limitation on applications of relaxor-PT material devices under harsh environment involving in high pressure and high temperature conditions. Structure evolution and phase transition of several solid solution ferroelectrics, such as Pb(YbNb)O3-PT (PYN-PT), have been studied using in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy techniques under high pressure and high temperature conditions. XRD results show pressure induced phase transitions to a cubic phase, while the persistence of Raman spectroscopy in the full pressure range indicates its local distortion. A pressure-temperature phase diagram is further constructed to determine the stability region of the ferroelectric phase. The results provide useful guidance for the applications of this kind of high Curie temperature ferroelectric crystal under extreme conditions, and extra clue to synthesis of ferroelectric materials with tailored properties.

In situphase transition study of nano- and coarse-grained TiO2under high pressure/temperature conditions

2008 ◽  
Vol 20 (12) ◽  
pp. 125224 ◽  
Author(s):  
Yuejian Wang ◽  
Yusheng Zhao ◽  
Jianzhong Zhang ◽  
Hongwu Xu ◽  
Liping Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Coarse Grained ◽  
Temperature Conditions ◽  
Transition Study

scholarly journals Integrated Laser-Induced Breakdown Spectroscopy (LIBS) and Multivariate Wavelet Tessellation: A New, Rapid Approach for Lithogeochemical Analysis and Interpretation

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 312
Author(s):  
Fernando F. Fontana ◽  
Steven Tassios ◽  
Jessica Stromberg ◽  
Caroline Tiddy ◽  
Ben van der Hoek ◽  
...  
Keyword(s):  
Rock Block ◽  
Coarse Grained ◽  
Geochemical Data ◽  
Laser Induced Breakdown Spectroscopy ◽  
Small Scale ◽  
Breakdown Spectroscopy ◽  
Novel Approach ◽  
Laser Induced Breakdown ◽  
Mineral Compositions ◽  
Plutonic Rocks

This paper demonstrates a novel approach that uses wavelet tessellation in rapid analysis of raw geochemical data produced by laser-induced breakdown spectroscopy (LIBS) to produce pseudologs that are representative of stratigraphy. Single-line LIBS spectral data for seven major rock-forming elements (Al, Ca, Fe, Mg, Si, Na and K) were collected from a synthetic 22-sample rock-block comprising two distinct lithological groups based on mineralogy, chemistry and texture: plutonic rocks and marble. Seven sublithologies are identified within the rock-block from traditional laboratory whole-rock geochemical analysis: marble, Mg-marble, granite, quartz monzonite, foidolite, granodiorite and gabbroic diorite. Two-domain clustering (k = 2) on raw spectral LIBS data combined with wavelet tessellation was applied to generate a simplified lithological stratigraphy of marble and plutonic rocks and generate a pseudolog identical to the rock-block stratigraphy. A pseudolog generated from seven-domain clustering (k = 7) and wavelet tessellation successfully discriminated most sublithologies within the rock-block slabs, especially marble slabs. Small-scale units were identified within the more mineralogically and geochemically complex plutonic slabs. The spatial resolution of the LIBS analysis, with a measurement spacing of ~0.35 mm, allowed for assessment of individual mineral compositions and rock textures, and small-scale units within the plutonic rocks can be correlated to specific coarse-grained minerals or mineralogical associations. The application of the wavelet tessellation method to raw LIBS geochemical data offers the possibility of rapid and objective lithogeochemical analysis and interpretations which can predate further analysis (quantitative) and supplement geological logging.

The Rewari meteorite

1979 ◽  
Vol 43 (327) ◽  
pp. 423-427
Author(s):  
S. P. Das Gupta ◽  
P. R. Sen Gupta ◽  
N. R. Sen Gupta ◽  
D. R. Das Gupta ◽  
A. Dube
Keyword(s):  
Chemical Analysis ◽  
Coarse Grained ◽  
Alteration Zone ◽  
Fragment Composition ◽  
Coarse Texture ◽  
The Matrix ◽  
Wet Chemical ◽  
High Degree ◽  
Lower Oxidation ◽  
Cut Surface

SummaryThe meteorite was an oriented polyhedron, which broke up into at least two parts after entry into the Earth's atmosphere. It has undergone some degree of terrestrial weathering. A cut surface of the meteorite shows light-grey interior with sporadic rusty-brown patches and a distinct brown alteration zone close to the fusion crust. Weathering has resulted in preferential replacement of NiFe by limonite, and veining of minerals by goethite.Rewari is an equilibrated chondrite with rare ghosts of chondrules and at least one lithic fragment. Composition of olivine, as indicated by microprobe analysis is Fa23, which agrees well with bulk wet chemical analysis; that indicated by d130 is Fa18–20. From the outer surface inwards, four petrographic zones can be distinguished in the meteorite: a skin, about 0.01 mm thick, a troilite-poor zone slightly thicker than the skin, a troilite-rich ‘soaking zone’, about 0.5–0.6 mm thick, and a relatively coarse-grained interior. These are described in detail.The interior of the meteorite is composed of relatively coarse-grained crystalline silicates with disseminated metallic minerals including plessitic and zoned inter-growths of kamacite and taenite. The matrix shows a high degree of integration with the chondrules. The coarse texture and zonation of taenite may be the result of protracted heat treatment responsible for recrystallization. The constituent grains show considerable shock effects such as fracturing, comminution, veins of shock-melted pseudotachylite, pressure twinning, and undulose extinction. Chemical composition (mean of two wet chemical analysis) of the meteorite is: metallic Fe 7.475, Ni 0.975, Co 0.045; as sulphide Fe 3.200, Ni 0.090, Co < 0.01; SiO2 38.060, TiO2 0.10, Al2O3 2.34, Fe2O3 0.175, Cr2O3 0.485, FeO 13.950, MnO 0.210, NiO trace, CaO 1.875, MgO 26.265, Na2O 0.89, K2O 0.115, P2O5 0.285, H2O− 0.295, H2O+ 0.81, CO2 trace, S (total) 1.890, C (total) 0.19 per cent. The chemistry, mineralogy, and texture show that the Rewari meteorite is an L6 chondrite. Compared to average L-group chondrite it has a higher content of MgO and lower of SiO2, a little lower oxidation state, and tends to be enriched in siderophilic elements.

Raman spectroscopy at mantle pressure and temperature conditions experimental set-up and the example of CaTiO3perovskite

1993 ◽  
Vol 20 (18) ◽  
pp. 1931-1934 ◽  
Author(s):  
Philippe Gillet ◽  
Guillaume Fiquet ◽  
Isabelle Daniel ◽  
Bruno Reynard
Keyword(s):  
Raman Spectroscopy ◽  
Temperature Conditions ◽  
Set Up
Sign in / Sign up

Export Citation Format

Share Document