Discrimination of metamorphic diamond populations by Raman spectroscopy (Kokchetav, Kazakhstan)

Metamorphic diamond is a powerful but frequently debated indicator for ultrahigh-pressure metamorphic (UHPM) conditions. Because of their small size, their optical identification needs confirmation. Characteristics of chemically extracted microdiamonds from Kokchetav, identified by different analytical methods, are used here for unambiguous in situ identification by Raman microspectroscopy. Differences appear in the diamond spectra and the Raman analytical method is explored as a helpful tool in the discrimination between diamond populations from four different UHPM lithologies of Kokchetav. Not considering the graphite-coated diamond, out of the reach of the laser wavelength used here, the comparison of these Kokchetav Raman spectra may provide additional information in other UHPM studies.     

Determination of fluorine by proton-induced gamma-ray emission (PIGE) spectrometry in igneous and metamorphic charnockitic rocks from Rogaland (S. W. Norway)

More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S. W. Norway) have been analysed by a direct non-destructive proton induced gamma-ray emission (PIGE) technique. The fluorine contents vary from <25 ppm to 3500 ppm. There is a good correlation between the concentration of fluorine and that of phosphorus for igneous rocks, suggesting a control of apatite on the F content. In metamorphic rocks, amphibole and biotite besides apatite are the principal cencentrators of fluorine indicating that fluorine in the system is controlled by granulite facies metamorphism conditions.Research Associate of the National Fund for Scientific Research (Belgium)     

Raman mapping of coesite inclusions in garnet from the Kokchetav Massif (Northern Kazakhstan)

Coesite inclusions occur in a wide range of lithologies and coesite is therefore a powerful ultrahigh-pressure (UHP) indicator. The transformation of coesite to quartz is evidenced by three optically well identifiable characteristics (e.g. palisade textures, radial crack patterns, polycrystalline quartz pseudomorphs). Under overpressure monomineralic coesite (on an optical basis), lacking the above transformation characteristics may survive. Raman micro-spectroscopy was applied on monomineralic coesite inclusions in garnet porphyroblasts from diamond-bearing garnet-clinozoisite-biotite gneisses of the Barchi-Kol area (Kokchetav Massif, Northern Kazakhstan). These coesite inclusions are euhedral and display a characteristic anisotropic hallo. However, Raman maps and separate spectra of these inclusions display shifted bands for coesite and quartz. Microscopically undetectable, quartz shows on the Raman map as a thin shell around coesite inclusion. Shift of the main coesite band allows to estimate their overpressure: coesite inclusions record 0-2.4 GPa in garnet and zircon. The quartz shell remains under lower pressure 0-1.6 GPa. The possible application of coesite and quartz Raman geobarometers for UHP metamorphic rocks is discussed.     

Fission track ages of Mahanshan Metamorphic Rock Group in Gansu Province, Northwest China

Fission track dating was used to determine the ultimate rock-forming epoch of Mahanshan Group of metamorphic rocks and involved granitite in NW China. The quartz and hornblende fission tracks revealed that Mahanshan metamorphic rocks were formed during 3.66-3.56^.10⁸ years before. Xiaoshima granitite rock body was dated 3.30-3.41^.10⁸ years which present the migmatization time in Mahan Shan Mountains area. Geological and geographical features indicate that the latter regional geological process should be dominated with physical tectonic activities including uplifting and fracturing.     

The Discovery and Geological Feature of Kyanite-Topazite in High-Pressure Belt From Central China

For the first time, we find kyanite-topazite which is similar to the white schist from abroad, in Jiangsu, Anhui, Henan of China. Because of intercontinental obduction and collision, the kyanite-topazite is formed from the superhigh-pressure metamorphism of sedimentary rock in continental crust, at the depth of mantle. Kyanite-topazite runs parallel to blue schist, eclogite and constitutes the high-pressure metamorphic belt in Central China. Its original rocks are a set of sedimentary rock series which is mainly composed of marginal shallow marine facies to continental facies pelitic to magnesium carbonatite, both rocks exist in Precambrian Middle-Upper Proterozoic metamorphic strata.     

Trace elements as geochemical markers for surface waters and groundwaters of the Var River catchment (Alpes Maritimes,France)

A geochemical study concerning surface waters and groundwaters from the Mediterranean Var River catchment (south-east France) is undertaken to better understand this hydrological system and to establish a hydro-geochemical natural background. Preliminary data show that geology of the catchment is sufficiently contrasted to give specific geochemical signatures to the different components of the catchment. Concentration ratios of selected trace elements allow defining (1) distinct natural domains for river groups inside the catchment, and (2) anthropogenic contributions. The Tinée tributary is affected by natural arsenic pollution, probably mainly originating from metamorphic rocks of the Mercantour massif.     

Influence of hydrothermal wood degradation products on the uranium adsorption onto metamorphic rocks and sediments

The influence of highly functionalized saccharic and phenolic polymers that are formed in the process of hydrothermal wood degradation on the uranium(VI) adsorption onto metamorphic rocks and sediments from the Saxon uranium mining sites Schlema-Alberoda and Königstein was investigated in a laboratory study. Uranium(VI) adsorption from a simulated mine water takes place on the majority of rocks and sediments such as granite, gneiss, basalt, sandstone and clay marl. Exceptions are phyllite and clay stone that do not bind any uranium from the mine water. Polymeric wood degradation products such as fragments of celluloses and lignin increase the uranium(VI) adsorption whereas the presence of saccharic and phenolic monomers (vanillic acid and gluconic acid) leads to a lower adsorption.     

Organo-silica nano-particles used in ultrahigh-pressure liquid chromatography

A simple one-step process was used to synthesize uniform, spherical organosilica nano-particles containing octadecyl moieties. These nano-particles, having a diameter of 670 nm, were slurry packed into fused-silica capillary tubes of 50 microm internal diameter and tested for use in ultrahigh-pressure liquid chromatography (UHPLC) at inlet pressures of about 50,000 psi (approximately 3,500 bar), providing for the use of HPLC with nano-particle packed columns. The retention characteristics of a column packed with the organo-nano-particles were shown to be stable under acidic (pH < 1) and basic (pH > 11) conditions. Fast analysis times and relatively high separation efficiencies (approximately 500,000 plates m(-1)) were obtained under the conditions used.     

Determination of traces of rare earth elements in geological samples

A procedure for the determination of traces of rare earth elements by inductively coupled plasma-optical emission spectrometry (ICP-OES) and X-ray fluorescence spectrometry (XRF) is presented. The samples are decomposed either by fusion with lithium tetraborate or by acid attack in a microwave oven. Separation of the rare earth elements from accompanying elements is achieved by anion exchange. For the determination by ICP-OES the samples are injected in hydrochloric acid solution, for the determination by XRF the rare earth element traces are co-precipitated with rhodizonate and tannin and measured as a thin film on a membrane filter. All preconcentration steps have been optimized and tested using radiotracers. Furthermore the rare earth element contents of some international standard reference rocks have been determined; the results are compared to the certified values and other values given in the literature. The procedure is applied to a series of petrographically identical metabasites with different degrees of metamorphism to show the mobility of those ions under metamorphic conditions.     

Oxyreactive Thermal Analysis of Dispersed Organic Matter, Kerogen and Carbonization Products A Tool for Investigation of the Heated Rock Masses

This paper presents the results of oxyreactive thermal analyses of organic matter in rocks, heated naturally during diagenetic to metamorphic processes. During the experiments we traced the reactions in the temperature range up to 900°C, it means from the very beginning of diagenetic transformations to the highest real temperatures acting in the Earth's crust as a solid phase. The results showed that TA could be a tool for the reconstruction of thermal regime in natural coal-bearing systems. This revised version was published online in August 2006 with corrections to the Cover Date.     

Rapid high performance liquid chromatography method development with high prediction accuracy,using 5 cm long narrow bore columns packed with sub-2 μm particles and Design Space computer modeling

Many different strategies of reversed phase high performance liquid chromatographic (RP-HPLC) method development are used today. This paper describes a strategy for the systematic development of ultrahigh-pressure liquid chromatographic (UHPLC or UPLC) methods using 5 cm × 2.1 mm columns packed with sub-2 μm particles and computer simulation (DryLab^® package). Data for the accuracy of computer modeling in the Design Space under ultrahigh-pressure conditions are reported. An acceptable accuracy for these predictions of the computer models is presented. This work illustrates a method development strategy, focusing on time reduction up to a factor 3–5, compared to the conventional HPLC method development and exhibits parts of the Design Space elaboration as requested by the FDA and ICH Q8R1. Furthermore this paper demonstrates the accuracy of retention time prediction at elevated pressure (enhanced flow-rate) and shows that the computer-assisted simulation can be applied with sufficient precision for UHPLC applications (p > 400 bar). Examples of fast and effective method development in pharmaceutical analysis, both for gradient and isocratic separations are presented.     

Separation of isomers of new psychoactive substances and isotope-labeled amphetamines using UHPSFC-MS/MS and UHPLC-MS/MS

The use of sub-2?µm particles columns is finding its use in ultrahigh-pressure supercritical fluid chromatography (UHPSFC), opening up for fast analysis and high-resolution separations. The development of new and more robust systems also makes the technique more interesting for bioanalytical analysis, where the need for reproducible and fast analysis with little downtime is great. One area where the use of UHPSFC could become a useful tool is in the separation of structural isomers of new psychoactive substances (NPS). 2-, 3-, and 4- structural isomers of fluoroamphetamine, fluoromethamphetamine, and methylmethcathinone, isomeric pairs of the synthetic cannabinoids UR-144/UR-144 degradant, XLR-11/XLR-11 degradant, JWH-015/JWH-073, and JWH-019/JWH-122, as well as amphetamine and several stable isotope-labeled amphetamine internal standards were separated with UHPSFC-MS/MS and compared with ultrahigh-pressure liquid chromatography (UHPLC) MS/MS. NPS isomers that were difficult to separate with reversed-phase UHPLC-MS/MS were separated by UHPSFC; in most cases with an orthogonal retention order to UHPLC. In contrast to the behavior seen when using reversed-phase UHPLC, the deuterated amphetamines eluted later than amphetamine with UHPSFC. ¹³C₆-labeled amphetamine coeluted with amphetamine for all conditions, making this the best choice of an internal standard.     

超高压液相色谱仪的研究进展及超高压引起的相关问题

超高压液相色谱中使用亚2 μm填料,以其高效、快速的特点已成为液相色谱发展的新方向之一。该文在回顾压力对液相色谱行为影响研究的基础上,对超高压液相色谱仪器的进展及相关问题加以系统综述,引文36篇。     

Raman spectroscopy of carbon and solid bitumens in sedimentary and metamorphic rocks

Different types of carbonaceous matter from rocks display Raman spectral features which knowledge permits to obtain structural information of these materials. Application of Raman microspectroscopy to investigate kerogen, bitumen, fossils, highly carbonified amorphous carbon as well as graphite from different environments is reviewed. Differences in Raman spectra and structural differences between carbonaceous samples differing in their metamorphic history are discussed on the basis of new data.     

Multiple Electron Beam Analyses Applied to Eclogite from the Western Alps

 The occurrence of compositional and microtextural relics within metamorphic rocks can provide useful information on the pressure-temperature history of the host rock. The grain-size of these microstructures, such as coronitic reaction microtextures, is mostly too fine to be detected by optical microscopy. Therefore, a more detailed analytical approach is needed. In this paper multiple electron beam techniques including the acquisition of X-ray multi-element maps, micro and nano-analysis performed by SEM/EDS and TEM/STEM-EDX systems were applied to a specific petrological problem related to metamorphism. Fine-grained decompressional reaction microtextures of an eclogitic sample (Mt. Rosa Nappe, Western Alps) are described and discussed.     

Molecular Simulation of the Adsorption Characteristics of Methane in Pores of Coal with Different Metamorphic Degrees

In order to study differences in the methane adsorption characteristics of coal pores of different metamorphic degrees, 4 nm pore structure models based on three typical coal structure models with different metamorphic degrees were constructed. Based on the molecular mechanics and dynamics theory, the adsorption characteristics of methane in different coal rank pores were simulated by the grand canonical Monte Carlo (GCMC) and molecular dynamics methods. The isothermal adsorption curve, Van der Waals energy, concentration distribution, and diffusion coefficient of methane under different conditions were analyzed and calculated. The results showed that at the same pore size, the adsorption capacity of CH₄ is positively correlated with pressure and metamorphic degree of coal, and the adsorption capacity of CH₄ in high metamorphic coal is more affected by temperature. The relative concentration of CH₄ in high-order coal pores is low, and the relative concentration at higher temperature and pressure conditions is high. The CH₄ diffusion coefficient in high-rank coal is low, corresponding to the strong Van der Waals interaction between CH₄ and coal. The research results are of great significance for further exploration of the interaction mechanism between CH₄ and coal with different metamorphic degrees and can provide theoretical support for the selection of gas extraction parameters.     

Chemical analysis of high-pressure metamorphic rocks by PGNAA: Comparison with results from XRF and solution ICP-MS

Summary High-pressure metamorphic rocks showing a large range of chemical compositions were analyzed by PGNAA, XRF and solution ICP-MS for major components and a variety of trace elements. The large data set allowed a comparison of results from PGNAA to the established methods and revealed good agreement for most major elements and for Sc and Gd. For V, Cr, Co and Ni, PGNAA data are satisfactory only at high concentration levels. B, Cl and H were analyzed by PGNAA with very good precision, even at low concentrations.     

Computer assisted multielement analysis of terrestrial and extraterrestrial materials and studies on long-lived cosmogenic53Mn by neutron activation

In a large number of alpine rocks and respective mineral separates the beryllium distribution was studied via “non-destructive” photon activation. The detection limit of the assembly was ∼20 ppb. The existence of Be-rich areas was revealed. A selection of individual rocks was analysed by instrumental as well as by radiochemical neutron activation analysis for main and trace elements as: Na, K, Sc, Cr, Mn, Fe, Co, Rb, Cs, La, Eu, Yb, Ta, W, Au, and U. The latter was determined by counting the²³⁵U-fission tracks. The data supply an insight into the complex processes leading to the formation of metamorphic rocks. The hardware and the computer evaluation of the γ-spectra is described in some detail. A further application is the determination of traces of⁵³Mn (in the order of 10⁻¹² g/g) produced by the interaction of cosmic rays with stony meteorites. From a comparison of the²⁶Al- and⁵³Mn-values it is concluded that the depth dependent production of these two radionuclides differs slightly.     

Iron speciation related to color of Jurassic sedimentary rocks in Turpan Basin, northwest China

Mesozoic-Cenozoic reddish and green beds are widely distributed in northwest China. Mössbauer spectroscopy revealed that the composition of iron species varies with color in the middle-upper Jurassic sedimentary rocks from the Turpan Basin. Three main kinds of iron species were identified: (1) ferric iron of hematite (hem-Fe³⁺), (2) paramagnetic ferric iron (para-Fe³⁺), and (3) paramagnetic ferrous iron (para-Fe²⁺). Pyrite iron (pyr-Fe²⁺) was revealed only in a few samples. In general, there is a direct correlation between rock color, iron species and total iron content, however, in detail, this relationship is more complicated. The reddish rocks contain higher contents of total iron and hem-Fe³⁺, whereas the gray rocks contain much more para-Fe²⁺. However, relatively low hematite content cannot give red color to rocks, probably due to suppression by other pigments such as organic matter in black or chlorite in green. The dark or green rocks normally contain either only paramagnetic Fe²⁺ and paramagnetic Fe³⁺ species or these two species associated with hematite Fe³⁺, but the relative content of hematite species is lower. The variations of different iron species control lithological properties such as color and also may reflect the sedimentary conditions. Moreover, iron speciation in these rocks is one of the main factors, which result the color features of rocks in remote sensing imagery.This revised version was published online in November 2005 with corrections to the Cover Date.     

EPMA Major and Trace Element Analysis in Garnet and its Petrological Application

 A comparison between major and trace element concentrations in garnet performed by electron microprobe (EPMA) technique is reported. Quantitative spot analyses and X-ray maps of major elements (Fe, Mg, Mn, Ca) and the trace element yttrium in garnets from metamorphic rocks are presented. The selected garnet samples come from meta-pelitic and meta-basic specimens belonging to the tectonic unit of the Monte Rosa Nappe (Western Alps). In the metapelites, the quantitative Y distribution maps display a prominent increase at the core, the Y abundance varying by over two orders of magnitude, from about 80 ppm (rim) to over 2100 ppm (core). The Y profiles show well defined patterns with sharp features that do not correlate with major element distributions. A roughly comparable pattern can be supposed only with Mn. The Y distribution suggests that the diffusion of Y through the garnet is very slow compared to the major elements, thus the Y results are suitable for geothermometric estimates. In the metabasites, the Y spatial distribution is characterised by an increasing content from the core to the rim, displaying a zoning pattern opposite to the metapelite garnet. Quantitative EPMA analyses range from 1100 ppm at the rim to values lower than the detection limit at the core. Therefore, the Y content in the garnet can be related to several chemical and physical variables such as the bulk rock composition and the phase assemblage. In particular, in the xenotime-bearing metapelitic system the Y distribution seems to be correlated with metamorphic peak temperature.