Petrology of the Yubileynaya kimberlite pipe: application to the variation of kimberlites composition with the depth

2020 ◽  
Author(s):  
Zdislav Spetsius ◽  
Alexander Ivanov
Keyword(s):  
Lithospheric Mantle ◽  
Original Data ◽  
Kimberlite Pipe ◽  
Essential Difference ◽  
Mineral Phases ◽  
Diamond Crystals ◽  
Essential Input ◽  
Indicator Minerals ◽  
Different Levels ◽  
Large Diamond

<p>In this paper are summarized investigation results on the chemistry, petrography and mineralogy of kimberlitic rocks of the upper and deep levels of the Yubileynaya pipe. There are given original data on mineral phases contents in kimberlite ground mass,distribution of indicator minerals and olivine and its pseudomorphoses as well as autoliths (pyroclasts) in kimberlite drill cores of different levels (-)280 – (-)680m.</p><p>Petrologic evidence suggest that for the kimberlites of the Yubileynaya pipe is characteristic the prevalence garnet association of indicator minerals with the relatively low their whole content, predominance oflherzolitic pyropes, low content of titanium garnets, two types of ilmenites and chromespinelides.The particularity of this pipe is the presence, both eclogite and garnet websterite xenoliths as well as their diamondiferous varieties. This evidence is confirmed also by the composition of the paragenic associations of indicator minerals that is indicative of essential difference of lithospheric mantle under this given pipe in contrast with nearby kimberlitic pipes. It is possible to speculate that these peculiarities are specific for the kimberlite pipes of the middle diamond productivity.</p><p>Results of the garnets chemistry and the data of the distribution of eclogitic and ultramafic garnets in kimberlite concentrate of this pipe with the taking in account quantity of garnet variety potentially associated with diamonds suggest anincreased prevalence of eclogitic garnets among indicator minerals. This allowed making a statement about essential input of eclogitic paragenesis diamonds in the whole diamond production of this pipe. In our opinion these peculiarities also determine the increased content of large diamond crystals in kimberlites of the Yubileynaya pipe.    </p>

scholarly journals The Tikiusaaq carbonatite: a new Mesozoic intrusive complex in southern West Greenland

2006 ◽  
Vol 10 ◽  
pp. 41-44 ◽  
Author(s):  
Agnete Steenfelt ◽  
Julie A. Hollis ◽  
Karsten Secher
Keyword(s):  
Lithospheric Mantle ◽  
Chemical Elements ◽  
Country Rock ◽  
Alkaline Rock ◽  
Geological Mapping ◽  
Carbonatite Complex ◽  
West Greenland ◽  
Alkaline Rocks ◽  
Kimberlite Indicator Minerals ◽  
Indicator Minerals

Ultrabasic alkaline magmatic rocks are products of melts generated deep within or at the base of the lithospheric mantle. The magmas may reach the surface to form lavas and pyroclastic deposits; alternatively they crystallise at depth to form dykes or central complexes. The rocks are chemically distinct and may contain high concentrations of economically interesting minerals and chemical elements, such as diamonds, niobium, tantalum, rare earth elements, phosphorus, iron, uranium, thorium, and zirconium. Ultrabasic alkaline rocks are known from several provinces in Greenland, but extrusive facies have only been preserved at a few places; e.g. at Qassiarsuk in South Greenland where pyroclastic rocks occur, and in the Maniitsoq region, where a small volcanic breccia (‘Fossilik’) contains fragments of Palaeozoic limestone. Ultramafic lamprophyre and kimberlite are mainly emplaced as dykes, whereas carbonatite forms large intrusive bodies as well as dykes. The ultrabasic alkaline magmas that have been emplaced at certain times during the geological evolution of Greenland can be related to major episodes of continental break-up (Larsen & Rex 1992). The oldest are Archaean and the youngest dated so far are Palaeogene. Figure 1 shows the distribution of known ultrabasic alkaline rocks in West Greenland. The large and well-exposed bodies of alkaline rocks and carbonatites in the Gardar Province were discovered already in the early 1800s (Ussing 1912), while less conspicuous bodies were discovered much later during geological mapping and mineral exploration. Many alkaline rock bodies, particularly dykes, are difficult to identify in the field because they weather more extensively than the country rock gneisses and form vegetated depressions in the landscape. However, their distinct chemistry and mineralogy render alkaline rocks identifiable in geochemical and geophysical survey data. Thus, the Sarfartôq carbonatite complex was discovered during regional airborne gamma-spectrometric surveying owing to its elevated uranium and thorium contents (Secher 1986). The use of kimberlite indicator minerals has led to the discovery of alkaline rocks such as kimberlites and ultramafic lamprophyres that carry fragments of deep lithospheric mantle. Such rocks may also contain diamonds. Kimberlite indicator minerals are high-pressure varieties of minerals, such as garnet, clinopyroxene, chromite and ilmenite that were formed in the lithospheric mantle. Exploration companies have processed thousands of till samples from southern West Greenland for kimberlite indicator minerals and found many new dykes.

Ratio of structural impurity distribution in diamond crystals and kimberlite pipe diamond potentiak (case study of Arkhangelsk region and Yakutia)

2021 ◽  
pp. 114-130
Author(s):  
Galina Khachatryan ◽  
Nataliya Anashkina
Keyword(s):  
Kimberlite Pipe ◽  
Impurity Distribution ◽  
Low Grade ◽  
Arkhangelsk Region ◽  
Negative Factor ◽  
Diamond Crystals ◽  
Thermodynamic Conditions ◽  
Structural Impurity ◽  
Diamond Potential

IR spectroscopy was used to compare diamonds from 12 pipes, Arkhangelsk region. Based on positive correlation between average N and H values in diamonds from various deposits, it was found that crystals from low-grade diamond pipes are relatively enriched in hydrogen compared with diamonds from Lomonosov and Grib deposits. In terms of structural impurity distribution, Arkhangelsk deposit diamonds differ from Yakutian diamonds; it could be due to various composition of compared diamonds’ source matter and thermodynamic conditions of their growth. It is shown that hydrogen is a negative factor of diamond potential in both Yakutian and Arkhangelsk diamonds. This can partly be explained by impuri-ty blocking effect on diamond crystal growth.

HPHT Growth and IR Characterizaton of Large Diamond Crystals in FeNi-C-FeS Systems

2011 ◽  
Vol 339 ◽  
pp. 491-495
Author(s):  
Chuan Yi Zang ◽  
Lun Jian Chen ◽  
Li Xue Chen
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Boron Content ◽  
Diamond Crystals ◽  
Growth System ◽  
Negative Effect ◽  
Temperature Gradient Method ◽  
Co Doped ◽  
Large Diamond

By temperature gradient method (TGM), with Invar alloy as solvent catalyst, FeS and boron as additives, large diamond crystals are grown under high pressure and high temperature (HPHT) of about 5.4GPa and 1550K. With the content of FeS increased, the colors of grown crystals would be changed from transparent yellow to opaque gray-black, and the quality of diamond crystals could also be destroyed markedly. When both boron and FeS co-doped, the negative effect of FeS on crystal quality could be eliminated somewhat. To a certain content of FeS, with the boron content increased, the crystal color would be changed from opaque gray-black to transparent yellow, and boron content needed is related directly to FeS content in growth systems. The nitrogen content in diamond lattice decreases greatly, with FeS content increased in the growth system, and a 1050cm-1 absorption peak in IR spectrum is also present in diamond crystals grown in FeNi-FeS-C system.

Metasomatic processes in the lithospheric mantle beneath the V. Grib kimberlite pipe (Arkhangelsk diamondiferous province, Russia)

2015 ◽  
Vol 56 (12) ◽  
pp. 1701-1716 ◽  
Author(s):  
E.V. Shchukina ◽  
A.M. Agashev ◽  
S.I. Kostrovitsky ◽  
N.P. Pokhilenko
Keyword(s):  
Lithospheric Mantle ◽  
Kimberlite Pipe

scholarly journals Digital Image Watermarking at Different Levels of DWT using RGB Channels

2020 ◽  
Vol 8 (5) ◽  
pp. 559-570
Keyword(s):  
Digital Image ◽  
Image Watermarking ◽  
Original Data ◽  
Extraction Process ◽  
Digital Image Watermarking ◽  
Watermark Image ◽  
The Common ◽  
Watermarking Scheme ◽  
Different Levels ◽  
Rgb Image

This paper presents a digital image watermarking scheme comprising of DWT transformation. Due to the common practice of creating the copy, transmitting and spreading the data duplication of the original data occurs. Digital image watermarking has the ability to provide a solution for the unauthorized duplication problem. The scheme designed and presented in this paper comprises of mainly two modules one for embedding the watermark within the cover image and another for retrieving the watermark from the watermarked image. The process is carried out at different levels of the DWT transformation within different sub-bands of the DWT transformation. The extraction process involves the extraction of the watermark image form different channels of the RGB image mainly red, green and blue. The robustness and imperceptibility are tested. In each of the case, the corresponding PSNR and correlation values are noted and the results obtained concludes the scheme as the robust, semi-fragile and fragile digital image watermarking at different levels of the DWT transformation

scholarly journals Unique Amphibole Bearing Mantle Column Beneath the Leningrad Kimberlite Pipe, West Ukukit Field, NE Yakutia

2021 ◽  
Author(s):  
Igor Victorovich Ashchepkov ◽  
Svetlana Anatolievna Babushkina ◽  
Nikolai Sergeevich Mevedev ◽  
Oleg Borisovich Oleinikov
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Trace Element ◽  
Partition Coefficients ◽  
Kimberlite Pipe ◽  
Basaltic Melt ◽  
Pressure Interval ◽  
Different Levels

In the subcratonic mantle beneath Leningrad pipe, West Ukukit field, Yakutia garnet thermoba-rometry give division to 7 horizons (paleosubduction slabs). Cr-bearing amphiboles >500 reveal a broad range changing from Cr- pargasitic hornblendes to pargasites, edinites, kataforites, К-richterites with increasing pressure determined with new amphibole thermobarometer. Cr-hornblendes compiles the high-temperature branch from 3.5 GPa to Moho for basaltic melt. Amphiboles in the middle eddinites and high-pressure interval reveal different PT ranges from 35 to 40 mw/m2. Richterites near the lithosphere base both trace low –T and convective branches. The amphiboles reveal the 9 geochemical groups. The low-temperature varieties reveal Eu minima and U, Ba, Sr peaks high LILE, Sr, Rb and troughs in Nb, Pb. While high –T varieties have no Eu dips and reveal higher HFSE. Clinopyroxenes and garnets show variable trace ele-ment patterns and divisions in groups eth the plume and subduction signs. The contrasting be-haviour of Ta and Nb is regulated by the rutile partition coefficients likely for primary eclogites. Subduction and Na and K (siliceous) types of fluids percolated through the mantle with abun-dant eclogites causing amphibolization at the different levels of the mantle column. The plume melts produced hybridism and more smooth trace element patterns in reacted minerals, clino-pyroxene. monomineral thermobarometry.

scholarly journals Oxidation State of the Lithospheric Mantle Beneath Komsomolskaya–Magnitnaya Kimberlite Pipe, Upper Muna Field, Siberian Craton

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 740 ◽  
Author(s):  
Anna Dymshits ◽  
Igor Sharygin ◽  
Zhe Liu ◽  
Nester Korolev ◽  
Vladimir Malkovets ◽  
...  
Keyword(s):  
Oxygen Fugacity ◽  
Oxidation State ◽  
Siberian Craton ◽  
Lithospheric Mantle ◽  
Redox State ◽  
Kimberlite Pipe ◽  
Good Explanation ◽  
Redox Conditions ◽  
Lateral Heterogeneity ◽  
Physical Processes

The oxidation state of the mantle plays an important role in many chemical and physical processes, including magma genesis, the speciation of volatiles, metasomatism and the evolution of the Earth’s atmosphere. We report the first data on the redox state of the subcontinental lithospheric mantle (SCLM) beneath the Komsomolskaya–Magnitnaya kimberlite pipe (KM), Upper Muna field, central Siberian craton. The oxygen fugacity of the KM peridotites ranges from −2.6 to 0.3 logarithmic units relative to the fayalite–magnetite–quartz buffer (∆logfO2 (FMQ)) at depths of 120–220 km. The enriched KM peridotites are more oxidized (−1.0–0.3 ∆logfO2 (FMQ)) than the depleted ones (from −1.4 to −2.6 ∆logfO2 (FMQ)). The oxygen fugacity of some enriched samples may reflect equilibrium with carbonate or carbonate-bearing melts at depths >170 km. A comparison of well-studied coeval Udachnaya and KM peridotites revealed similar redox conditions in the SCLM of the Siberian craton beneath these pipes. Nevertheless, Udachnaya peridotites show wider variations in oxygen fugacity (−4.95–0.23 ∆logfO2 (FMQ)). This indicates the presence of more reduced mantle domains in the Udachnaya SCLM. In turn, the established difference in the redox conditions is a good explanation for the lower amounts of resorbed diamonds in the Udachnaya pipe (12%) in comparison with the KM kimberlites (33%). The obtained results advocate a lateral heterogeneity in the oxidation state of the Siberian SCLM.

Growth of Large Diamond Crystals by Reduction of Magnesium Carbonate with Metallic Sodium.

ChemInform ◽  
2003 ◽  
Vol 34 (51) ◽  
Author(s):  
Zhengsong Lou ◽  
Qianwang Chen ◽  
Wei Wang ◽  
Yitai Qian ◽  
Yufeng Zhang
Keyword(s):  
Magnesium Carbonate ◽  
Metallic Sodium ◽  
Diamond Crystals ◽  
Large Diamond
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