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1.
A.?A.?NosovaEmail authorView author&#;s OrcID profile L.?V.?Sazonova A.?V.?Kargin M.?D.?Smirnova A.?V.?Lapin V.?D.?Shcherbakov 《Contributions to Mineralogy and Petrology》2018,173(7):55
We studied olivines from the Devonian pre-trap (the Ilbokich occurrence) and the Triassic post-trap (the Chadobets occurrence) carbonate-rich ultramafic lamprophyres (UMLs) in the southwestern portion of the Siberian craton. On the basis of detailed investigations of major, minor, and trace-element distributions, we have reconstructed the main processes that control the origins of these olivines. These include fractional crystallisation from melt, assimilation, and fractional crystallisation processes with orthopyroxene assimilation, melt-reaction diffusive re-equilibration, alkali enrichment, and CO2 degassing of the melt. Furthermore, we inferred the composition of the sources of the primary UML melt and their possible correlations with proto-kimberlitic melts, as well as the influence of the Triassic Siberian plume on the composition of the lithospheric mantle. The main differences between olivines from the Ilbokich and the Chadobets aillikites were that the olivines from the former had more magnesium-rich cores (Mg# = 89.2?±?0.2), had Mg- and Cr-rich transition zones (Mg# = 89.7?±?0.2 and 300–500 ppm Cr), had lower Ni (up to 3100 ppm) and Li (1.4–1.5 ppm), and had higher B (0.8–2.6 ppm) contents, all at higher Fo values (90–86), relative to the olivines from the latter (Mg# = 88–75; 200–300 ppm Cr; up to 3400 ppm Ni; 1.4–2.4 ppm Li; 0.4–2.2 ppm B). The Siberian aillikite sources contained a significant amount of metasomatic material. Phlogopite-rich MARID-type veins provided the likely metasomatic component in the pre-trap Devonian Ilbokich aillikite source, whereas the Triassic Chadobets aillikitic post-trap melts were derived from a source with a significant carbonate component. A comparison of UML olivines with olivines from the pre-trap and post-trap Siberian kimberlites shows a striking similarity. This suggests that the carbonate component in the aillikitic source could have been produced by evolved kimberlite melts. The differences in the lithospheric metasomatic component that contributed to pre-trap and post-trap aillikitic melts can be interpreted as reflections of the thermal impact of the Siberian Traps, which reduced phlogopite-bearing metasomes within the southwestern Siberian sub-continental lithospheric mantle. 相似文献
2.
L. V. Sazonova V. V. Milyavskii T. I. Borodina S. N. Sokolov A. Z. Zhuk 《Izvestiya Physics of the Solid Earth》2007,43(8):707-712
The shock metamorphism of plagioclase and amphibole of various chemical compositions from amphibolite and granulite facies schists was studied in experiments with shock wave loading of samples in steel recovery ampoules of plane geometry. A maximum shock pressure was reached after a few circulations of waves in the sample (stepwise shock wave compression) and varied within 26–52 GPa. The recovered samples were examined by the methods of scanning electron microscopy and microprobe and X-ray phase analysis. It is established that an increase in the F, Ti, and K concentrations in amphibole and a decrease in the Ca concentration in plagioclase make these minerals more stable with respect to shock waves. It is shown that the migration of some chemical elements, starting already at the solid phase stage of transformation in plagioclase and amphibole, is intensified at the stage of melting. It is established that isotropization of plagioclase occurs through two different mechanisms. At relatively low pressures, it is caused by the fragmentation of substance at the microlevel and is accompanied by the formation of maskelynite, a typical mineral of meteorites and astrobleme rocks. At higher pressures, isotropization is associated with melting-induced amorphization. 相似文献
3.
The paper presents a concise review of results obtained by studying shock metamorphism of polymineralic rocks with the application of spherical hermetically sealed recovery devices. Such experiments are proved to be able to reproduce principally important features of transformations detected in rocks from natural meteoritic craters (astroblemes). The experimental samples show subspherical concentric zones with different rock transformations, which are generally analogous to zones in natural astroblemes (listed in order from the centers of the spherical samples to their margins): fracturing, diaplectic transformations, selective and then complete melting, and finally, evaporation. However, the laboratory scale of the experiments and the absence of younger overprinted processes, which can obliterate impact transformations of rocks in nature, enable the researcher to reveal distinctive compositional, textural, and phase features of transformations induced in the rocks at increasing isentropic shock wave-induced loading. Data on the mobility of major elements in the course of impact metamorphism show that the type and certain features of the crystal structures of minerals are of paramount importance for the amorphization of the minerals or their shock wave-induced thermal decomposition. The crystal chemical control of mineral transformations was proved to be exerted at a number of levels. High-pressure phases identified in experiments with shock wave loading were determined to crystallize from melt or via a phase transition associated with the migration of elements. 相似文献
4.
The analysis of available theoretical evaluations and experimental data reveals discrepancies and makes it possible to formulate the goals for the comprehensive study of the behavior of enstatite MgSiO3 in shock isentropic waves of various scale and intensity. The paper presents the layout and results of an explosion experiment on the compression of an enstatite sphere with spherical shock waves and the subsequent recovery of the experimental material and its examination in discrete zones (along the sphere radius) that were produced by shock waves in the material. The latter were examined with the application of scanning electron microscopy, Raman spectroscopy, and X-ray diffraction analysis. The comparison of the systematic variations in the texture, chemistry, and phase composition of enstatite along the sphere radius with calculated pressure P(R, t) and temperature T(R, t) values led us to the following conclusions: enstatite starts melting on an isentrope upon pressure relief after shock wave compression at ?? xx ?? 80 GPa and melts on the front of the spherically converging shock wave at ?? xx ?? 160 GPa and T ?? 6300 K. Our laboratory experiments with shock waves were the world??s first in which enstatite was loaded with spherical converging shock isentropic waves and which provided evidence that shock wave-loaded MgSiO3 shows certain morphological and mineralogical features never before detected in this mineral loaded with plane shock wave of smaller amplitude and duration. Goals are formulated for the further studying of shock wave-loaded materials, and the necessity is discussed for conducting an explosion experiment with a five to seven times greater spherical system in order to increase the duration of the shock wave loading impulse. 相似文献
5.
Yu. O. Larionova L. V. Sazonova N. M. Lebedeva A. A. Nosova V. V. Tretyachenko A. V. Travin A. V. Kargin D. S. Yudin 《Petrology》2016,24(6):562-593
The paper reports detailed data on phlogopite from kimberlite of three facies types in the Arkhangelsk Diamondiferous Province (ADP): (i) massive magmatic kimberlite (Ermakovskaya-7 Pipe), (ii) transitional type between massive volcaniclastic and magmatic kimberlite (Grib Pipe), and (iii) volcanic kimberlite (Karpinskii-1 and Karpinskii-2 pipes). Kimberlite from the Ermakovskaya-7 Pipe contains only groundmass phlogopite. Kimberlite from the Grib Pipe contains a number of phlogopite populations: megacrysts, macrocrysts, matrix phlogopite, and this mineral in xenoliths. Phlogopite macrocrysts and matrix phlogopite define a single compositional trend reflecting the evolution of the kimberlite melt. The composition points of phlogopite from the xenoliths lie on a single crystallization trend, i.e., the mineral also crystallized from kimberlite melt, which likely actively metasomatized the host rocks from which the xenoliths were captured. Phlogopite from volcaniclastic kimberlite from the Karpinskii-1 and Karpinskii-2 pipes does not show either any clearly distinct petrographic setting or compositional differentiation. The kimberlite was dated by the Rb–Sr technique on phlogopite and additionally by the 40Ar/39Ar method. Because it is highly probable that phlogopite from all pipes crystallized from kimberlite melt, the crystallization age of the kimberlite can be defined as 376 ± 3 Ma for the Grib Pipe, 380 ± 2 Ma for the Karpinskii-1 pipe, 375 ± 2 Ma for the Karpinskii-2 Pipe, and 377 ± 0.4 Ma for the Ermakovskaya-7 Pipe. The age of the pipes coincides within the error and suggests that the melts of the pipes were emplaced almost simultaneously. Our geochronologic data on kimberlite emplacement in ADP lie within the range of 380 ± 2 to 375 ± Ma and coincide with most age values for Devonian alkaline–ultramafic complexes in the Kola Province: 379 ± 5 Ma; Arzamastsev and Wu, 2014). These data indicate that the kimberlite was formed during the early evolution of the Kola Province, when alkaline–ultramafic complexes (including those with carbonatite) were emplaced. 相似文献
6.
A. V. Kargin A. A. Nosova A. V. Postnikov A. V. Chugaev O. V. Postnikova L. P. Popova V. V. Poshibaev L. V. Sazonova A. Ya. Dokuchaev M. D. Smirnova 《Geology of Ore Deposits》2016,58(5):383-403
The results of geochronological, mineralogical, petrographical, and geochemical study of the Ilbokich ultramafic lamprophyre are reported. The specific features in the mineral and chemical compositions of the studied ultramafic lamprophyre indicate that it can be regarded as a variety similar to aillikite, while other differences dominated by K-feldspar can be referred to damtjernite. According to Rb–Sr analysis, ultramafic lamprophyre dikes intruded at the turn of the Early and Middle Devonian, about 392 Ma ago. This directly proves the existence of Early Paleozoic alkali–ultramafic magmatism in the northern part of the southwest Siberian Platform. A finding of Devonian alkali–ultramafic lamprophyre is of dual predictive importance. On the one hand, it is indicative of the low probability of finding large diamond-bearing deposits in close association with aillikite. On the other hand, it can be indicative of a possible large Devonian diamond province in the studied territory, where diamondiferous kimberlite is structurally separated from aillikite. 相似文献
7.
Mesoproterozoic olivine gabbronorites of the Bashkirian anticlinorium,the South Urals: Parental melts and specifics of magma evolution 总被引：1，自引：0，他引：1
A. A. Nosova L. V. Sazonova V. M. Gorozhanin O. F. Kuz’menkova E. O. Dubinina 《Petrology》2010,18(1):50-83
This paper is devoted to detailed study of picritic rocks (olivine melanogabbronorites) and comagmatic gabbrodolerites from
sills and dikes in the central part of the Bashkirian meganticlinorium. These rocks are ascribed to the Kama-Belsk magmatic
province (KBP) that was formed in the eastern East European Platform (EEP) in the Mesoproterozoic time. The study of minerals
(EMPA, SIMS), rocks, and their oxygen isotope compositions showed the contribution of crustal contamination, fractional crystallization
and cumulus processes in their formation. The geochemical indicators of crustal contamination (Nb/Nb*, (Nb/La)
n
, δ18O, and others) show strong variations, which indicates uneven crustal contribution in the parental melts during rock formation
(10–25%). The study of weakly contaminated (δ18O = 5.3‰) olivine melanogabbronorites (MgO = 22.55 wt %) from the small Ishlya-1 subvolcanic body, which contain subordinate
amount of cumulus (24%), high-magnesian olivine (Fo91.3), and high-Cr spinel (cr# 0.67), as well as HREE depleted clinopyroxenes, allowed us to retrieve the composition of parental
melt. The latter contained about 20 wt % MgO and was formed by 19–26% melting of mantle source (potential mantle temperature
T
m of 1530–1545°C).
Geochemical characteristics of KBP reflect the formation of primary melts by melting of mantle column at different depths,
mixing of the melts, and significant contamination by crustal material. The dominant role in the formation of the rocks of
the Ishlya area and Mashak Complex was played by derivatives of spinel peridotites, while the rocks of the Bakal-Satka area
were derived from garnet peridotites. 相似文献
8.
V. I. Fel’dman L. V. Sazonova V. V. Milyavskii T. I. Borodina S. N. Sokolov A. Z. Zhuk 《Izvestiya Physics of the Solid Earth》2006,42(6):477-480
The shock metamorphism of schist consisting of garnet, biotite, quartz, and plagioclase is studied under shock wave loading of a sample in steel recovery ampoules of plane geometry. A maximum shock pressure was reached during several circulations of waves in the sample (stepwise shock compression) and varied within the range 19–52 GPa. The recovered samples were examined by the methods of scanning electron microscopy and microprobe and X-ray phase analysis. The results were compared with natural impactites and with shock-induced alterations in minerals loaded by a spherical convergent wave. It is established that, given a plane geometry of loading (stepwise shock compression), solid-state transformations at the lattice level (migration of chemical elements and formation of shock thermal aggregates) are not observed in all of the studied minerals, in contrast to natural impact processes and spherical geometry experiments. Under the conditions of our experiments, minerals melt at higher pressures than in the case of natural impact processes and spherical geometry experiments. However, for each mineral studied, the mechanical strain patterns at close shock pressures are, on the whole, the same for all of the aforementioned three variants of shock wave loading. 相似文献
9.