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91.
Vladimir Frid Gady Liskevich Dmitriy Doudkinski Nikolay Korostishevsky 《Environmental Geology》2008,53(7):1503-1508
This paper deals with an employment of electrical resistivity imaging (ERI) for survey of leachate content on the waste disposal
site in Northern Israel. The research consisted of conducting ten ERI lines and drilling investigation wells. Data simulation
used a 2D EarthImager inversion program. Analysis of 2D ERI interpretation results shows that determination of the boundary
between the landfill body bottom intensively saturated with leachates and underlying layers of highly water saturated fat
nonconsolidated clays presents a challenge. However, statistical analysis of ERI data indicates that standard deviation and
confidence interval of a set of resistivity data measured in the landfill body are significantly larger than those in underlying
clays. Moreover, maximum changes of these parameters are found on the boundary between landfill body and underlying soil,
thus reflecting natural differences in scattering of resistivity data measured in these two objects. 相似文献
92.
Composition of the Siberian cratonic mantle: evidence from Udachnaya peridotite xenoliths 总被引:31,自引:0,他引:31
F. R. Boyd N. P. Pokhilenko D. G. Pearson S. A. Mertzman N. V. Sobolev L. W. Finger 《Contributions to Mineralogy and Petrology》1997,128(2-3):228-246
Bulk compositions and mineral analyses for forty-one, large, garnet- and spinel-facies peridotite xenoliths from the Udachnaya
kimberlite in the central Siberian platform have many similarities to those of well-studied peridotites from the Kaapvaal
craton in southern Africa. Coarse Mg-rich lherzolites and harzburgites with equilibration temperatures below 1000 °C are abundant
and are believed to form the principal rock type in the Siberian lithosphere. The low-temperature Udachnaya peridotites have
an average mg number [Mg/(Mg+Fe)] of 92.6 with a wide dispersion in modal enstatite, ranging to over 40 wt%. High-temperature
peridotites are relatively richer in Fe and Ti and are commonly deformed, with porphyroclastic or mosaic-porphyroclastic textures,
some of the latter having fluidized enstatite. The Udachnaya peridotites have experienced late-stage metasomatism before,
during and after eruption. Garnets and pyroxenes in many of the high-temperature rocks are zoned, probably by reaction with
melt prior to eruption. Virtually all the peridotites contain secondary diopside, inhomogeneous on a micron scale, that mantles
primary orthopyroxene. It is believed to have crystallized along with lesser amounts of intergranular calcite and monticellite
during eruption. Bulk analyses for total Fe in many specimens are higher than whole-rock Fe calculated from the electron probe
analyses and the modes. The magnitude of the difference between the two measurements of total Fe correlates with loss-on-ignition,
suggesting that Fe has been introduced during serpentinization following eruption. These late metasomatic processes have thus
affected some major as well minor and trace element compositions. The similarities in bulk composition of peridotites from
Udachnaya and the Kaapvaal are evidence of a common origin. Low-temperature cratonic peridotites differ from oceanic peridotites
in having higher mg numbers (>92) and in having relatively high but wide-ranging modal enstatite (Mg/Si = 1.06–1.49 weight
fraction). The Udachnaya low-temperature peridotites have an inverse correlation between FeO (calculated from the probe analyses
and modes) and SiO2. This correlation is also present in the Kaapvaal data but is complicated by a greater range in fertility that produces a
positive variation of Fe with Si. A negative trend for Fe/Si can be seen within a portion of the Kaapvaal data, that for low-Ca
harzburgites, in which the variation in fertility is restricted. The negative trends for Fe/Si can be interpreted as a consequence
of either segregation of olivine and orthopyroxene by metamorphic differentiation or partial sorting during cumulate formation.
Received: 18 June 1996 / Accepted: 11 February 1997 相似文献
93.
Snyder Gregory A.; Taylor Lawrence A.; Crozaz Ghislaine; Halliday Alex N.; Beard Brian L.; Sobolev Vladimir N.; Sobolev Nikolai V. 《Journal of Petrology》1997,38(1):85-113
Owing to the association with diamonds, eclogite xenoliths havereceived disproportionate attention given their low abundancein kimberlites. Several hypotheses have been advanced for theorigin of eclogite xenoliths, from the subduction and high-pressuremelting of oceanic crust, to cumulates and liquids derived fromthe upper mantle. We have amassed a comprehensive data set,including major- and trace-element mineral chemistry, carbonisotopes in diamonds, and Rb–Sr, Sm–Nd, Re–Os,and oxygen isotopes in ultrapure mineral and whole-rock splitsfrom eclogites of the Udachnaya kimberlite pipe, Yakutia, Russia.Furthermore, eclogites from two other Yakutian kimberlite pipes,Mir and Obnazhennaya, have been studied in detail and offercontrasting images of eclogite protoliths. Relative to eclogitesfrom southern Africa and other Yakutian localities, Udachnayaeclogites are notable in the absence of chemical zoning in mineralgrains, as well as the degree of light rare earth element (LREE)depletion and unradiogenic Sr; lack of significant oxygen, sulfur,and carbon isotopic variation relative to the mantle; and intermineralradiogenic isotopic equilibration. Several of these eclogitescould be derived from ancient, recycled, oceanic crust, butmany others exhibit no evidence for an oceanic crustal protolith.The apparent lack of stable-isotope variation in the Udachnayaeclogites could be due to the antiquity of the samples and consequentlack of deep oceanic and biogenically diverse environments atthat time. Those eclogites that are interpreted to be non-recycledhave compositions characteristic of Group A eclogites from otherlocalities that also have been interpreted as being directlyfrom the mantle. At least two separate and diverse isotopicreservoirs are suggested by Nd isotopic whole-rock reconstructions.Most samples were derived from typical depleted mantle. However,two groups of three samples each indicate both enriched mantleand possible ultra-depleted mantle present beneath Yakutia duringthe late Archean and early Proterozoic. The vast majority ofeclogites studied from the Obnazhennaya pipe also exhibit characteristicsof Group A eclogites and are probably derived directly fromthe mantle. However, the eclogites from the Mir kimberlite aremore typical of other eclogites world-wide and show convincingevidence of a recycled, oceanic crustal affinity. We concurwith the late Ted Ringwood that eclogites can be formed in avariety of ways, both within the mantle and from oceanic crustalresidues. KEY WORDS: diamonds; eclogite xenoliths; isotopic composition; REE; Yakutia 相似文献
94.
A. N. Kruk A. G. Sokol D. A. Chebotarev Yu. A. Palyanov N. V. Sobolev 《Doklady Earth Sciences》2016,467(1):303-307
Generation of ultra-alkaline melts by the interaction of lherzolite with cardonatites of various genesis was simulated at the P–T parameters typical of the base of the subcratonic lithosphere. Experiments with a duration of 150 h were performed at 5.5 and 6.3 GPa and 1350°C. The concentrations of CaO and MgO in melts are buffered by the phases of peridotite, and the concentrations of alkalis and FeO depend on the composition of the starting carbonatite. Melts are characterized by a low (<7 wt %) concentration of SiO2 and Ca# from 0.40 to 0.47. It is demonstrated that only high-Mg groups of carbonatitic inclusions in fibrous diamonds have a composition close to that of carbonatitic melts in equilibrium with lherzolite. Most likely, the formation of kimberlite-like melts relatively enriched in SiO2 requires an additional source of heat from mantle plumes and probably H2O fluid. 相似文献
95.
Yu. V. Bataleva Yu. N. Palyanov Yu. M. Borzdov N. V. Sobolev 《Doklady Earth Sciences》2016,471(1):1144-1148
Experimental research in the Fe3C–(Fe,Ni)S system was carried out. The objective of the investigation was to model the reactions of carbide–sulfide interaction related to graphite (diamond) formation in reduced lithosphere mantle domains. T ≤ 1200°C is the formation temperature of the Ni-cohenite + graphite assemblage coexisting with two immiscible melts such as sulfide (Fe60–Ni3–S37)L and metal–sulfide (Fe71–Ni7–S21–C1)L containing dissolved carbon. Т ≥ 1300°C is the generation temperature of a unified melt such as (Fe80–Ni6–S10–C4)L characterized by graphite crystallization and diamond growth. The extraction of carbide carbon during the interaction with the sulfide melt can be considered as one of the potential mechanisms of graphite and diamond formation in the reduced mantle. 相似文献
96.
A. A. Tomilenko T. A. Bul’bak L. N. Pokhilenko D. V. Kuzmin N. V. Sobolev 《Doklady Earth Sciences》2016,469(1):690-694
The composition of volatile components in picroilmenites from Yakutian kimberlitic pipes of various ages (the Olivinovaya, Malokuonapskaya, and Udachnaya–East pipes) was studied for the first time by means of gas chromatography–mass spectrometry (GC-MS). It was shown that picroilmenites and olivines from same kimberlitic pipes contained volatile components of close composition, whereas these components were quite different in these minerals from different pipes. These features point to a common source and represent the specificity of the magma chamber formed under the pronounced influence of hydrocarbons with their derivates, as well as nitrogen-, chlorine-, and sulfur-containing compounds. The fraction of hydrocarbons and derivates in the composition of volatile matter is as high as 99%, including 9.7% of chlorine- and fluorinecontaining compounds. 相似文献
97.
The Crosa and Boynton (1980) empirical model for discrete mass transfer in Her X-1 is further developed. The photometric features of the light curve (peaks of an hour duration and 0.3–0.7
m
amplitude, steps near orbital phase =0); and the linear polarization bursts are assumed to be due to the formation and eclipses of the plasma blobs produced by discrete transfer of matter from optical star surface and its interaction with the accretion disc rim. The long lifetime (20h) of the cold (3×104 K) blob extending up to 1011 cm above the disc plane, as well as the deep X-ray flickerings (300 s) during the X-ray absorption dips are assumed to arise from a dispersal of accreting matter by the Rayleigh-Taylor instability in a blob moving through a hot corona of the disk atT
c
=3×106 K andn
c
=3×1011 cm–3. Thermal equilibrium in the corona and in the blobs are supported by X-ray flux. Within the first few hours after its formation a blob disintegrates into drops withr=5×109 cm,T=3×104 K, andn=3×1013 cm–3 which move then along Keplerian orbits. Frictional interactions of the drops with the corona destroy them on a 20h time-scale. The proposed model makes it possible to interpret the diverse observational facts and to predict numerous observational displays in the optical, UV, and X-ray bands. The first results of our optical-spectrum observations of blobs are briefly described. 相似文献
98.
Brune Sascha Ladage Stefan Babeyko Andrey Y. Müller Christian Kopp Heidrun Sobolev Stephan V. 《Natural Hazards》2010,54(2):547-562
Our analysis of new bathymetric data reveals six submarine landslides at the eastern Sunda margin between central Java and
Sumba Island, Indonesia. Their volumes range between 1 km3 in the Java fore-arc basin up to 20 km3 at the trench off Sumba
and Sumbawa. We estimate the potential hazard of each event by modeling the corresponding tsunami and its run-up on nearby
coasts. Four slides are situated remarkably close to the epicenter of the 1977 tsunamigenic Sumba M
w
= 8.3 earthquake. However, comparison of documented tsunami run-up heights and arrival times with our modeling results neither
allows us to confirm nor can we falsify the hypothesis that the earthquake triggered these submarine landslides. 相似文献
99.
Andrey A. Gurenko Kaj A. Hoernle Alexander V. Sobolev Folkmar Hauff Hans-Ulrich Schmincke 《Contributions to Mineralogy and Petrology》2010,159(5):689-702
The Canary Island primitive basaltic magmas are thought to be derived from an HIMU-type upwelling mantle containing isotopically
depleted (NMORB)-type component having interacted with an enriched (EM)-type component, the origin of which is still a subject
of debate. We studied the relationships between Ni, Mn and Ca concentrations in olivine phenocrysts (85.6–90.0 mol.% Fo, 1,722–3,915 ppm
Ni, 1,085–1,552 ppm Mn, 1,222–3,002 ppm Ca) from the most primitive subaerial and ODP Leg 157 high-silica (picritic to olivine
basaltic) lavas with their bulk rock Sr–Nd–Pb isotope compositions (87Sr/86Sr = 0.70315–0.70331, 143Nd/144Nd = 0.51288–0.51292, 206Pb/204Pb = 19.55–19.93, 207Pb/204Pb = 15.60–15.63, 208Pb/204Pb = 39.31–39.69). Our data point toward the presence of both a peridotitic and a pyroxenitic component in the magma source.
Using the model (Sobolev et al. in: Science 316:412–417, 2007) in which the reaction of Si-rich melts originated during partial
melting of eclogite (a high pressure product of subducted oceanic crust) with ambient peridotitic mantle forms olivine-free
reaction pyroxenite, we obtain an end member composition for peridotite with 87Sr/86Sr = 0.70337, 143Nd/144Nd = 0.51291, 206Pb/204Pb = 19.36, 207Pb/204Pb = 15.61 and 208Pb/204Pb = 39.07 (EM-type end member), and pyroxenite with 87Sr/86Sr = 0.70309, 143Nd/144Nd = 0.51289, 206Pb/204Pb = 20.03, 207Pb/204Pb = 15.62 and 208Pb/204Pb = 39.84 (HIMU-type end member). Mixing of melts from these end members in proportions ranging from 70% peridotite and 30%
pyroxenite to 28% peridotite and 72% pyroxenite derived melt fractions can generate the compositions of the most primitive
Gran Canaria shield stage lavas. Combining our results with those from the low-silica rocks from the western Canary Islands
(Gurenko et al. EPSL 277:514–524, 2009), at least four distinct components are required. We propose that they are (1) HIMU-type
pyroxenitic component (representing recycled ocean crust of intermediate age) from the plume center, (2) HIMU-type peridotitic
component (ancient recycled ocean crust stirred into the ambient mantle) from the plume margin, (3) depleted, MORB-type pyroxenitic
component (young recycled oceanic crust) in the upper mantle entrained by the plume, and (4) EM-type peridotitic component
from the asthenosphere or lithosphere above the plume center. 相似文献
100.
Trace elements in garnets and chromites: Diamond formation in the Siberian lithosphere 总被引:1,自引:0,他引:1
W.L. Griffin N.V. Sobolev C.G. Ryan N.P. Pokhilenko T.T. Win E.S. Yefimova 《Lithos》1993,29(3-4):235-256
Proton-microprobe analyses of trace elements in garnet and chromite inclusions in diamonds (DI) from the Mir, Udachnaya, Aikhal and Sytykanskaya kimberlites in Yakutia, CIS, provide new insights into the processes that form diamond. Equivalent data on garnet and chromite concentrates from these pipes yield information on the thermal state and chemical stratification of the Siberian lithosphere. Peridotite-suite diamonds from Yakutia have formed over a temperature interval of ca. 600°C, as measured by Ni and Zn thermometry on garnet and chromite inclusions in diamonds. Individual diamonds contain inclusions recording temperature intervals of >400°C; ranges of >100°C are common. Diamond formation followed a severe depletion event(s), and a separate enrichment in Sr. Comparison of temperatures on DI garnet and spinel with temperatures derived from diamondiferous harzburgites, exposed inclusions in boart and concentrate minerals suggests that the diamond-containing part of the lithosphere has cooled significantly since the Siberian diamonds crystallized. The peridotite-suite diamonds probably formed mainly in response to one or more relatively short-lived thermal events, related to magmatic intrusion. The northern part of the Daldyn-Alakit district may have had a typical cratonic geotherm at the time of diamond formation, and during kimberlite intrusion. The southern part of the district, and the Malo-Botuobiya kimberlite field, probably had a relatively low geotherm (ca. 35 mW/m2). The vertical distribution of garnet and chromite types indicates that the mantle above 120 km depth is dominated by lherzolites, whereas the deeper parts of the lithosphere are a mixture of lherzolites and more depleted harzburgites and dunites. 相似文献