Mineralogical and geochemical features of mantle xenoliths from diamond bearing kimberlites of China and Yakutia

2020 ◽  
pp. 21-27
Author(s):  
S. S. Vorobei ◽  
V. K. Garanin ◽  
E. A. Minervina ◽  
T. V. Posukhova ◽  
Xia Wei Sheng
Keyword(s):  
Mantle Xenoliths ◽  
Microbeam Analysis ◽  
Icp Ms ◽  
Genetic Features

Xenoliths from the Mir pipe and from Shandong and Liaoning provinces were studied according to electron microbeam analysis and ICP-MS. Their mineralogical, geochemical and genetic features are revealed. Minerals of diamondiferous paragenesis were established in xenoliths of the Mir pipe, but not in xenoliths of China. All xenoliths have secondary changes. They are stronger in the xenoliths of China. The distribution of REE shows the involvement of subduction processes in the formation of xenoliths from the Mir pipe. They are not found in xenoliths from China; the influence of metasomatism is clearly manifested in them. РТparameters were calculated: Т=600700 °С, Р=22,5 GPa. They do not correspond to mantle settings and reflect the conditions of metasomatic processes.

scholarly journals Supplemental Material: Three-stage modification of lithospheric mantle: Evidence from petrology, in-situ trace elements, and Sr isotopes of mantle xenoliths in the Cenozoic basalts, northeastern North China Craton

2021 ◽  
Author(s):  
Xinran Xu ◽  
Yanjie Tang ◽  
et al.
Keyword(s):  
Trace Elements ◽  
North China Craton ◽  
North China ◽  
Major Element ◽  
Equilibrium Temperature ◽  
Mantle Xenoliths ◽  
Sr Isotopes ◽  
Temperature Estimation ◽  
Icp Ms

Table S1: Petrological information and equilibrium temperature estimation for the studied samples; Table S2: Major element compositions (wt%) of minerals; Table S3: Trace element concentrations (ppm) of Cpx in xenoliths determined by LA-ICP-MS; Table S4: In situ Sr isotopic compositions of Cpx in the xenoliths.

scholarly journals Supplemental Material: Three-stage modification of lithospheric mantle: Evidence from petrology, in-situ trace elements, and Sr isotopes of mantle xenoliths in the Cenozoic basalts, northeastern North China Craton

2021 ◽  
Author(s):  
Xinran Xu ◽  
Yanjie Tang ◽  
et al.
Keyword(s):  
Trace Elements ◽  
North China Craton ◽  
North China ◽  
Major Element ◽  
Equilibrium Temperature ◽  
Mantle Xenoliths ◽  
Sr Isotopes ◽  
Temperature Estimation ◽  
Icp Ms

Table S1: Petrological information and equilibrium temperature estimation for the studied samples; Table S2: Major element compositions (wt%) of minerals; Table S3: Trace element concentrations (ppm) of Cpx in xenoliths determined by LA-ICP-MS; Table S4: In situ Sr isotopic compositions of Cpx in the xenoliths.

scholarly journals Thermobarometry and Geochemistry of Mantle Xenoliths from Zapolyarnaya Pipe, Upper Muna Field, Yakutia: Implications for Mantle Layering, Interaction with Plume Melts and Diamond Grade

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 755
Author(s):  
Igor Ashchepkov ◽  
Nikolay Medvedev ◽  
Nikolay Vladykin ◽  
Alexander Ivanov ◽  
Hilary Downes
Keyword(s):  
Alkali Metals ◽  
Mantle Xenoliths ◽  
Pressure Groups ◽  
Icp Ms ◽  
Melt Percolation ◽  
Pt Path ◽  
Two Stages ◽  
Diamondiferous Kimberlite ◽  
Very High ◽  
Feeding Systems

Minerals from mantle xenoliths in the Zapolyarnaya pipe in the Upper Muna field, Russia and from mineral separates from other large diamondiferous kimberlite pipes in this field (Deimos, Novinka and Komsomolskaya-Magnitnaya) were studied with EPMA and LA-ICP-MS. All pipes contain very high proportions of sub-calcic garnets. Zapolyarnaya contains mainly dunitic xenoliths with veinlets of garnets, phlogopites and Fe-rich pyroxenes similar in composition to those from sheared peridotites. PT estimates for the clinopyroxenes trace the convective inflection of the geotherm (40–45 mW·m−2) to 8 GPa, inflected at 6 GPa and overlapping with PT estimates for ilmenites derived from protokimberlites. The Upper Muna mantle lithosphere includes dunite channels from 8 to 2 GPa, which were favorable for melt movement. The primary layering deduced from the fluctuations of CaO in garnets was smoothed by the refertilization events, which formed additional pyroxenes. Clinopyroxenes from the Novinka and Komsomolskaya-Magnitnaya pipes show a more linear geotherm and three branches in the P-Fe# plot from the lithosphere base to the Moho, suggesting several episodes of pervasive melt percolation. Clinopyroxenes from Zapolyarnaya are divided into four groups according to thermobarometry and trace element patterns, which show a stepwise increase of REE and incompatible elements. Lower pressure groups including dunitic garnets have elevated REE with peaks in Rb, Th, Nb, Sr, Zr, and U, suggesting mixing of the parental protokimberlitic melts with partially melted metasomatic veins of ancient subduction origin. At least two stages of melt percolation formed the inclined PT paths: (1) an ancient garnet semi-advective geotherm (35–45 mW·m−2) formed by volatile-rich melts during the major late Archean event of lithosphere growth; and (2) a hotter megacrystic PT path (Cpx-Ilm) formed by feeding systems for kimberlite eruptions (40–45 mW·m−2). Ilmenite PT estimates trace three separate PT trajectories, suggesting a multistage process associated with metasomatism and formation of the Cpx-Phl veinlets in dunites. Heating associated with intrusions of protokimberlite caused reactivation of the mantle metasomatites rich in H2O and alkali metals and possibly favored the growth of large megacrystalline diamonds.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Abstract #1061: Cribriform-Morular Variant Thyroid Cancer(C-MV TC): Clinical, Histopathological and Genetic Features

2015 ◽  
Vol 21 ◽  
pp. 222
Author(s):  
Mohammed Ahmed ◽  
Abdulrahman Alkabbani ◽  
Tarek Amin ◽  
Hindi Alhindi
Keyword(s):  
Thyroid Cancer ◽  
Genetic Features ◽  
Cribriform Morular Variant

Ethical Issues Relevant to the Assessment of Suicide Risk in Nonclinical Research Settings

Crisis ◽  
2012 ◽  
Vol 33 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Carolyn M. Wilson ◽  
Bruce K. Christensen
Keyword(s):  
Undergraduate Students ◽  
Suicide Risk ◽  
Ethical Issues ◽  
Current Paper ◽  
Self Report ◽  
Ethical Guidelines ◽  
Schizotypal Personality ◽  
Increased Risk ◽  
Genetic Features ◽  
Conducting Research

Background: Our laboratory recently confronted this issue while conducting research with undergraduate students at the University of Waterloo (UW). Although our main objective was to examine cognitive and genetic features of individuals with schizotypal personality disorder (SPD), the study protocol also entailed the completion of various self-report measures to identify participants deemed at increased risk for suicide. Aims and Methods: This paper seeks to review and discuss the relevant ethical guidelines and legislation that bear upon a psychologist’s obligation to further assess and intervene when research participants reveal that they are at increased risk for suicide. Results and Conclusions: In the current paper we argue that psychologists are ethically impelled to assess and appropriately intervene in cases of suicide risk, even when such risk is revealed within a research context. We also discuss how any such obligation may potentially be modulated by the research participant’s expectations of the role of a psychologist, within such a context. Although the focus of the current paper is on the ethical obligations of psychologists, specifically those practicing within Canada, the relevance of this paper extends to all regulated health professionals conducting research in nonclinical settings.

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