Nicolae Buzgar

Natural samples containing tetrahedrite–tennantite, bournonite–seligmannite and geocronite–jordanite from the Coranda-Hondol ore deposit, Romania, were investigated by Raman spectroscopy to determine its capability to provide estimates of solid solutions in three common and widespread sulfosalt mineral series. Raman measurements were performed on extended solid solution series (Td1 to Td97, Bnn25 to Bnn93 and Gcn24 to Gcn67, apfu). The tetrahedrite–tennantite and bournonite–seligmannite solid solution series show strong correlations between spectroscopic parameters ( position, relative intensity and shape of the Raman bands) and the Sb/(Sb+As) content ratio, while Raman spectra of geocronite–jordanite shows no evolution of Raman bands. In order to simplify the method used to estimate the Sb/(Sb+As) content ratio in tetrahedrite–tennantite and bournonite–seligmannite series, several linear equations of the first-order polynomial fit were obtained. The results are in good agreement wi...

The Copou-Iaşi area is one of the oldest from the well-known vineyard region of Moldavian Platform (Eastern Romania). A number of 36 plots soil samples were systematically collected from a 0–40 cm depth. Soil profiles nearby the plots were sampled for the geochemical assessment of potentially toxic elements (PTE), using deep soil layers as controlled reference samples. The collected samples were analyzed for a series of 18 elements using ED-XRF method. The assessment of soil contamination was carried out by PCA multivariate statistic method and some geochemical indices (EF, AC,CF, CD) were calculated in addition. The obtained data shows an enrichment of PTE for the upper soil layer and denote an anthropogenic source due to the specifically disturbance of vineyards soils. Comparing to the Romanian legislation in force Cr, Ni, Pb and As exceed the normal values, but are within the alert threshold. Only Cu content exceed the Romanian alert threshold. A special attention is required in ...

Three-dimensional (3D) minerals and rocks in the form of interactive, engaging, and immersive experiences are of paramount importance to the geoscience community, researchers, students, and philomaths. Moreover, the SARS-CoV-2 (COVID-19) crisis affecting our society in the spring of 2020 highlighted the importance of 3D material in geoscience education — compared to 2D images, the three-dimensional models provide a better way to learn and to recognize different minerals and rocks, properties, textures, etc. This paper seeks to provide a comprehensive method to create an interactive scientific, learning, and cultural heritage environment in the field of Geosciences. In this paper, we overcome most of the Structure-from-Motion - Multi-View Stereo (SfM-MVS) photogrammetry limitations, where samples with a transparent, translucent, or glossy surface are a real challenge for the feature detection algorithms of the SfM workflow. Correct lighting setup, the usage of cross-polarized light p...

Minor elements received more attention in recent years due to their contamination susceptibility and environmental impact. Surface sediment samples were collected from 29 sites and total contents of eight minor elements (Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) were investigated in order to determine the geostatistical distribution and to predict ecological implications. The relationship between metals and ecological implications was analyzed by using the geochemical normalization approach and ecological prediction indicators such as the enrichment factor (EF), the contamination degree (CD), the environmental toxicity quotient (ETQ), and the health risk assessment. Based on the studied toxic metals, it was observed that the most toxic element in Tazlău River sediments is Cr. The assessment results of carcinogenic and non-carcinogenic risks via dermal contact indicate that the study area shows no human health risk. The correlation matrix and principal component analysis (PCA) provide an o...

In this paper, we are presenting an experimental method for the analysis of ceramic samples based on Raman VIS radiation spectroscopy. The samples include ancient ceramics, discovered in archaeological sites located in the region of Moldavia (NorthEastern Romania), as well as fake samples obtained by experimental archaeometry. In order to determine the optimum classification criteria for the ceramic samples, we have developed a software application, called P_Raman, using the Pascal programming language. By extension, this method may also be applied to trace the origin of industrially-manufactured ceramics.

Abstract The Coranda-Hondol ore deposit (Certej, Romania) is a sulfide ore deposit that was mined primarily for gold, silver, lead, and zinc. Secondary minerals were formed through a precipitation process from sulfate solutions with a high concentration of dissolved metals (especially Fe). These sulfate solutions resulted from acid mine drainage. Fourteen waste samples were analyzed through Raman spectrometry, X-ray diffraction, and scanning electron microscopy. Fe 3+ -, Fe 2+ -, Cu-, Zn-, Ca-, Mg-, and MnAl-hydrated sulfates were identified. All are unstable when exposed to the laser beam of the Raman spectrometer. Coquimbite, copiapite, ferricopiapite, hydroniumjarosite, and gunningite turn into anhydrous forms or oxides, depending on the laser power. Gypsum turns into bassanite, while apjohnite loses all water molecules at 53.6 mW laser power on the surface of the sample. Rhomboclase, melanterite, rozenite, antlerite, and brochantite break down without forming new minerals. Fe 2+ -sulfates do not change into hematite under laser irradiation. Epsomite and hexahydrite are stable at 53.6 mW laser power.

Raman spectroscopy is a simple, powerful and fast method to identify and distinguish between different minerals from the amphibole group of the inosilicate class. We analyzed samples of grunerite, actinolite, nephrite, Cr actinolite (smaragdite), uralite (var. ...

Abstract The sulfosalt minerals are of great importance for a better understanding of ore forming conditions and mineralization distribution, especially in the case of hydrothermal deposits. So far, few Raman studies were conducted on this type of minerals. In the present work, were studied several samples from Baia Sprie ore deposit, Romania—a worldwide classic example for hydrothermal mineralizations. Bismuthinite, lillianite-gustavite, heyrovskyite, cosalite, tetrahedrite-tennantite, bournonite and semseyite have been analyzed using electron microprobe and Raman spectrometry. The Raman spectra of bismuth sulfosalts, Ag-rich tetrahedrite and semseyite are discussed for the first time. The Bi sulfosalts show typical ν 1 symmetric stretching modes of the MS 6 octahedra at 286–279 cm −1 , ν 2 stretching at 216–207 cm −1 and ν 5 bending modes at 140–112 cm −1 . The transition from tetrahedrite to tennantite is very clearly observed in the Raman spectra. Several changes are marked through the solid solution, as the Sb—As isomorphic substitution takes place. Therefore, as the composition changes from As-member (tennantite) to the Sb-member (tetrahedrite), a shifting trend is observed in the Raman spectra, especially for the fundamental modes. The spectra of bournonite are dominated by two very strong lines at 325 and 296 cm −1 . The Raman band at 331 cm −1 in semseyite is assigned to ν 1 symmetric stretching modes of the octahedra. The ν 2 stretching is observed at 212 cm −1 , while the bending mode ν 5 appears at 148–143 cm −1 .

The present paper analyses the distribution of two elements (K and P) with nutrition role in the soils of the apple orchards located in the NE of Romania. Three types of soil samples were collected; topsoil (0-20 cm) from the apple-tree rows, soil samples from the 20-40 cm depth interval and topsoil (0-20 cm) from the middle of the apple tree rows. Soil analyses were performed by means of EDXRF at the Geology department of "Al. I. Cuza" University from Iai. K and P c oncentrations were obtained from the K2O and P2O5 total content in soils. Using specialized software distribution maps were created. The distribution tendency of the two elements shows that there is a quantifiable accumulation closer both to surface and the apple tree rows. The soil supply with P and the linear correlations between the elements and pH and CaCO3 were also determined.

Some of the most common sulfates have been investigated by non-contact Raman spectrography. For barite and anhydrite group the vibrational mode ν1 decreseas as the atomic mass increseas.The Raman spectrum of chalcocyanite shows two strong bands at 1013 cm-1 and 1045 cm-1 interpreted as ν1 modes. The bands at 423 cm-1, 448 cm-1, 480 cm-1 and 514 cm-1 have been assigned to the ν2 sulfate mode, the bands at 1101 cm-1 and 1205 cm-1 to the ν3 vibrational modes and the bands at 622 cm-1 and 670 cm-1 to the ν4 mode of SO4. The bands at 250 cm-1, 269 cm-1 and 347 cm-1 have been interpreted as vibrations of Cu-O bonds. Szmikite shows intense vibrations at1021 cm-1 interpreted as ν1 mode of SO4. The ν2 and ν3 modes the bands are at 425 cm-1 and 493 cm-1 respectively 1089 cm-1 and 1189 cm-1. The bands at 623 cm-1 and 654 cm-1 were assigned to the ν4 mode. The translational mode T(H2O, Mn) was determined at 263 cm-1.

Raman and infrared spectral studies were performed on six natural minerals from the doublechain silicate group. We analyzed samples of grunerite, actinolite, tremolite, pargasite (+kaersutite) and riebeckite in order to determine the spectral differences between them and to identify the vibrations that occur. Also, for one sample thought to be pargasite we obtained the Raman spectrum of kaersutite, while another sample was determined as a Ti-rich pargasite, since the difference between these two minerals consists in the presence of more than 0.50 apfu Ti in kaersutite (titaniferous calcic amphibole). The Raman spectrum of kaersutite exhibits characteristic bands of the Ti-OH vibration around 580–590 cm and 750 cm. These two bands are stronger than the symmetric stretching vibration of the Si-Ob-Si (ν1), which arises as the strongest band in all other amphibole minerals of the present study, around 650–670 cm. Both Raman and infrared spectra of all the analyzed samples reveal the pre...

The black pigment of 112 Cucuteni A and Cucuteni B pottery has been analyzed through Raman spectroscopy. The black pigment contains pyrolusite and jacobsite; quartz and anatase have only accidentally been observed. Black Carbon was also identified, but only in two samples. The spherical or oblate black corpuscles discovered at Feteşti-La Schit (Suceava county) were analyzed by means of X-ray diffractometry and Raman spectroscopy. They consist of Mn ± Fe oxihydroxides and quartz. No Mn carbonates or silicates have been identified. The mineralogical composition of the pigment applied to the pottery shards, as well as that of the raw pigment, together with the use of the same pigment over a long period of time (1100 years), suggest the exploitation of a large sedimentary mineral deposit, such as the Mn sedimentary ores from Nikopol (Ukraine).

Some of the most common carbonates have been investigated by non-contact Raman spectroscopy. The synthetic alkali carbonates K2CO3 and Na2CO3 have also been studied. The Raman spectrum of aurichalcite is different from that of malachite. This spectrum has a characteristic intense band at 1069 cm -1 which is assigned to the ν1 symmetric stretching mode of the carbonate unit. The two low intensity Raman lines of 1485 and 1507 cm -1 may be ascribed to the ν3 asymmetric stretching modes. To the ν4 mode (doubly degenerate symmetric bending) are attributed the values of 706 cm -1 (ν4a) and 733 cm -1 (ν4b). A number of bands with different intensities are observed in the lowest spectral shift (285, 388, 430, 461 and 498 cm -1 ). These Raman lines are assigned to the CuO and ZnO stretching and bending vibrations. A single band of the OH-stretching modes is observed at 3344 cm -1 .

Masuda and Ikeuchi (1978) were the first to observe the lanthanide tetrad effect in the marine environment and before them, the same behavior of REEs was described in non–geological disciplines by Fidelis and Siekierski (1966) and Peppard et al. (1969) who observed the tetrad effect in patterns of liquid–liquid REE distribution coefficients. In non–geological disciplines it is also described as “nephelauxetic effect” (Jorgenson, 1970), “inclined W effect” (Sinha, 1978) or “double–double effect” (Mioduski, 1997).

The white, red and black pigments from 50 ceramic sherds of the phase A of the Cucuteni culture were analyzed using Raman spectroscopy. For the white pigment, the Raman spectra indicated the presence of TiO2 and quartz. CaCO3 was not revealed in any of the samples. For the white pigment, a kaolinite white clay, rich in TiO2 and quartz, formed from the weathering of acid igneous rocks, was used. For the red pigment, a clay rich in Fe oxyhydroxides, subjected to an artificial process of Fe oxyhydroxide enrichment, was used. The Raman spectra indicated the presence of hematite and quartz. As far as the black pigment is concerned, jacobsite and, in only one sample, black carbon or graphite were identified. The source of the manganese black pigment can be explained by secondary accumulations of Mn from the Iacobeni-Ciocăneşti region (Romania) and/or the manganese ore from Nikopol (Ukraine). The red ceramic paste also contains hematite and quartz, just like the red pigment. The raw black ...

A thoroughly experimental and theoretical spectroscopic study (Surface-enhanced Raman Spectroscopy (SERS), Raman and FT-IR) concerning the structure of N-(2-cyanoethil)-imidazole have been performed. Limited information is bringing by Raman Spectroscopy, but when absorbed on the surface of the silver nanoparticles, strong vibrational signals were recorded. The influence of aggregation ions (F-, Cl-, Br-, I-) and the influence of pH on the adsorption mechanism was investigated. Ab initio HF and density functional theory calculation were carried out to compute the wavenumbers of N-(2-cyanoethil)-imidazole. All theoretical and experimental vibrational frequencies for N-(2-cyanoethil)-imidazole were carefully assigned, and are in agreement to each other.

In the current study, different heavy minerals typical of gold placer deposits were identified by means of micro-Raman spectroscopy, and their chemical composition analyzed and discussed (garnet, kyanite, staurolite, zircon, allanite, monazite, xenotime, rutile, anatase, cassiterite, titanite, barite). Even complex solid solution series, such as those of garnets, can be deciphered with the aid of systematic trends observed in Raman line frequencies. The ν1 mode in garnets will shift from high to low frequencies as a function of the ionic radius of the X2+ cation, from Mg2+, to Fe2+ and Mn2+, while the presence of Ca2+ will make the band to be shifted strongly to even lower wavenumbers. This approach has successfully been taken to differentiate between polymorph triplets such as kyanite-sillimanite-andalusite and rutile-anatase-brookite. Minerals under consideration with high contents of REE, U and Th are affected by intensive metamictization, particularly zircon and titanite. Raman ...

Tinovul Mare Poiana Stampei is situated in the northern group of the Oriental Carpathians within the Dornelor Depression, one of the richest peat areas in Romania. In this study we have performed analyses of certain heavy metals (Cr, Co, Ni, Cu, Zn, Pb, As and Cd) found in the forest soils adjacent to the Tinovul Mare Poiana Stampei peat bog. The analyses performed through X-ray fluorescence spectrometry indicated the following variation limits (mg/kg): Cr: 20-66; Co: 8-29; Ni: 16-78; Cu: 16-42; Zn: 36-199; Pb: 21-229; As: 5.5-36 and Cd: 0.01-1.4. The outcomes of the present study indicate high concentrations for certain (Ni, Pb and As). These concentrations exceed the alert threshold established by the Romanian Law, according to Order no. 756 of November, 3rd 1997.

In the current study, different heavy minerals typical of gold placer deposits were identified by means of micro-Raman spectroscopy, and their chemical composition analyzed and discussed (garnet, kyanite, staurolite, zircon, allanite, monazite, xenotime, rutile, anatase, cassiterite, titanite, barite). Even complex solid solution series, such as those of garnets, can be deciphered with the aid of systematic trends observed in Raman line frequencies. The ν1 mode in garnets will shift from high to low frequencies as a function of the ionic radius of the X2+ cation, from Mg2+, to Fe2+ and Mn2+, while the presence of Ca2+ will make the band to be shifted strongly to even lower wavenumbers. This approach has successfully been taken to differentiate between polymorph triplets such as kyanite-sillimanite-andalusite and rutile-anatase-brookite. Minerals under consideration with high contents of REE, U and Th are affected by intensive metamictization, particularly zircon and titanite. Raman ...

The study of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) and As found in the topsoil (0-25 cm) of the Falticeni municipality and some of its surroundings has generally indicated the presence of contents belonging to the geochemical natural background, with some interferences associated with urban soils and areas covered with orchards or other crops, onto which fertilizers and pesticides are applied intensively. The highest values for Co do not exceed the maximum accepted threshold (MAT) in Romania. For Cd and Cr, there are, in small areas, contents over the MAT in Romanian soils. Some of the concentrations obtained for As, Cu, Ni and Zn exceed the alert threshold, but they are still far below the intervention threshold for sensitive terrains. Pb is the only heavy metal whose maximum content is higher than the intervention threshold for a sensitive terrain; however, only one sample out of the 63 analyzed is over this threshold. It is certainly the case of a punctual contaminati...

The mineral samples analysed in this paper belong to the tourmaline group and were separated from granitic pegmatite specimens collected from the Contu-Negovanu area, in the Southern Carpathians (Romania). Tourmaline is a complex borosilicate of variable composition, including at least 12 recognized and hypothetical end-members of solid-solution series and a great number of varieties: schorl, dravite, elbaite etc. Our investigations on tourmaline samples concern X-ray powder diffraction and optical measurements, as well as chemical analysis, by means of EMPA and X-ray fluorescence techniques. The X-ray powder diffraction data (lambda = 0.1518 nm) enabled the identification of the precise tourmaline end-members as dravite-schorl, and to a lesser extent foitite and uvite. Unit-cell parameters were also calculated using a computer program for lattice parameter refinement. The main refractive indices have been interferometrically determined using the monochromatic yellow radiation of a ...

The Baia Sprie epithermal system, a well-known deposit for its impressive mineralogical associations, shows the proper conditions for acid mine drainage and can be considered a general example for affected mining areas around the globe. Efflorescent samples from the abandoned open pit Minei Hill have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and near-infrared (NIR) spectrometry. The identified phases represent mostly iron sulfates with different hydration degrees (szomolnokite, rozenite, melanterite, coquimbite, ferricopiapite), Zn and Al sulfates (gunningite, alunogen, halotrichite). The samples were heated at different temperatures in order to establish the phase transformations among the studied sulfates. The dehydration temperatures and intermediate phases upon decomposition were successfully identified for each of mineral phases. Gunningite was the single sulfate that showed no transformations during the heating experiment. All the other sulfates started to dehydrate within the 30-90°C temperature range. The acid mine drainage is the main cause for sulfates formation, triggered by pyrite oxidation as the major source for the abundant iron sulfates. Based on the dehydration temperatures, the climatological interpretation indicated that melanterite formation and long-term presence is related to continental and temperate climates. Coquimbite and rozenite are attributed also to the dry arid/semi-arid areas, in addition to the above mentioned ones. The more stable sulfates, alunogen, halotrichite, szomolnokite, ferricopiapite and gunningite, can form and persists in all climate regimes, from dry continental to even tropical humid.

The study of the heavy metal contents in the soils of the suburban area of Iaşi municipality is required due to the necessity of estimating the possible hazard that they can have over health. So far, in Iaşi municipality, such studies had a punctual character, aiming mostly towards the neighborhoods of some industrial objectives. In order to establish the quantities of heavy metals in soils and the qualitative description of the soils there have been sampled 582 of systematic analysis, determining the contents of Zn, Cu, Mn, Pb, Cd, Co, Ni and Cr. The pollution index (PI) and integrated pollution index (IPI) indicates a reduced anthropogeneous influence. Despite this, the high heavy metal contents levels (Cu, Ni, Pb, Zn), surpassing the normal values in soils, suggests the existence of some local sources, generating pollution.

11 fragments of wall painting from the Beroe fortress, Romania (4th –6th century) were analysed through Raman spectroscopy. The yellow-brown pigment on the fragments is jarosite and/or Na-jarosite. Other than at 445 cm-1, the Raman lines of all the spectra are identical. This Raman line is slightly shifted in different spectra, and this fact proves the presence of both jarosite and Na-jarosite.

The Răzoare formation, part of the Preluca Mountains from NW Romania, is the host of granitic pegmatites rich in garnets. The large garnet grains of dark pink colour are associated with quartz, muscovite and albite. Generally, garnet is a common accessory mineral in granitic pegmatites associated with granite, and its composition denotes the nature of the crystallization environment. The investigated garnets display a significant spessartine content (about 30 mol %), which is typical for garnets from magmatic pegmatites. The REE pattern and the Y, Li, Nb/Ta, Zr/Hf and Sc contents support the magmatic origin of the pegmatites investigated. This sum of geochemical features points to the development of the rocks from a peraluminous melt rich in volatile components which are involved in the enhancement of trace element mobility during the differentiation processes.

In this paper are presented the preliminary results of studies concerning the composition, structure and stability of organic-mineral complexes from hortic anthrosols. The separation of organic-mineral complexes has been performing by isodynamic magnetic method and by extraction in aqueous Na 2 SO 4 –polyethylene glycol two-phase systems. The composition and structure of organic-mineral complexes have been studied by Raman, FT-IR and UV-VIS spectroscopy, optic microscopy, thermal and chemical analysis. In studied horthic antrosol, the content of organic-mineral complexes varied between 20.42-48.36 % [w/w], being evidenced a relative accumulation tendency in Ahok (48.36 %) horizon and in grain size fractions < 0.002 mm (63.62-86.30 %, from total determined organic-mineral complexes), respectively. The maximum weight (29.45-64.56 %) has been observed at grain size fractions < 0.001 mm. The high apparition frequencies and stability have organic-mineral complexes which include in ...

Some of the most common pyroxenes (bronzite, hypersthene, diopside, hedenbergite, augite, omphacite, aegirine and spodumene) and pyroxenoids (wollastonite, rhodonite, fowlerite and charoite) have been investigated by non-contact Raman spectroscopy. In order to complete the information on the vibrational modes, the IR spectrum of augite was devised. In the Raman spectrum of aegirine, the bands appear at lower wavenumbers than in the rest of the pyroxenes. The bands assigned to the Si-O vibrational modes are split due to the deformation of the tetrahedra. In the rhodonite and zinc-rich variety (fowlerite) spectra, differences were noted; in fowlerite, some bands are shifted at higher frequencies, compared with rhodonite. The pyroxenoids presented the same typical bands of the single-chain structure. The spectrum of charoite shows two new lines at 2367 cm-1 and 2403 cm-1, which are due to the modes of the N-H bonds.

Preliminary investigations were carried out on secondary minerals formed by weathering in the Minei Hill open pit (Baia Sprie deposit, Romania). Several samples were analyzed using vibrational spectroscopy (Raman and FT-IR) in order to identify the mineral species formed by the weathering of the main ore minerals. The Raman spectra revealed the presence of hydrated iron sulfate – rozenite (FeSO4 · 4H2O) and a hydrated zinc sulfate – either bianchite (Zn,Fe)SO4 · 6H2O) or goslarite (ZnSO4 · 7H2O). The IR spectra of the weathering product indicated the presence of rozenite and goslarite. These two minerals are products of sphalerite and pyrite weathering. No lead sulfates were identified in Raman or IR spectra. The presence of rozenite and goslarite can represent a source for environmental contamination.

ABSTRACT The city of Iasi is located in the NE part of Romania and the geology of the area is typical of Moldavian Platform (SW section of East-Europe Platform). The soil was sampled according to a 500 x 500 m grid in the surrounding area of the city. Thus, the soil of different land use category (arable land, forest land, meadows land, vineyardorchard land) was collected from the depth of 0-40 cm. Also the soil bedrocks were randomly sampled in natural outcrops and in profiles from excavations. The soil bedrocks represent non-fissile yellow – brownish clays laying over Sarmatian fissile clays. The analysis of samples (pallet of 2 mm soil fraction) was performed using EDXRF method. The purpose of the present work is to assess the trace elements (As, Ni, Cu, Zn, Pb) ambient background (AB) of soil and the geogenic background (GB) of soil bedrocks. The ambient and geogenic background were evaluated by two statistic methods (median±2MAD; cumulative frequency curves) according to data distribution for land use category and on the entire data set. The AB of forest and meadow soil is closed to the geogenic background. The AB of all trace elements assessed on the base of entire data set (including all land categories) attains higher upper limits. The enhancement of AB range results from increasing contribution of anthropogenic fraction in soil owing to the arable and vineyard lands. However, the ambient background of studied trace elements does not exceed the alert range stated by Romanian legislation. The soil bedrock background support the entirely ambient background ranges.