Evaluation of landfill disposal boundary by means of electrical resistivity imaging

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.     

Composition of a carbonatitic melt in equilibrium with lherzolite at 5.5–6.3 GPa and 1350°C

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.     

Peculiarities of the composition of volatile components in picroilmenites from Yakutian kimberlites of various ages (by gas chromatography—mass spectrometry)

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.     

The accretion matter at the disk rim in Her X-1/HZ Her

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 (20^h) 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 20^h 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.     

Submarine landslides at the eastern Sunda margin: observations and tsunami impact assessment

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.     

Source components of the Gran Canaria (Canary Islands) shield stage magmas: evidence from olivine composition and Sr–Nd–Pb isotopes

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.     

Trace elements in garnets and chromites: Diamond formation in the Siberian lithosphere

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.