Earth-Based Support for the Titan Saturn System Mission     

Athena Coustenis  Jonathan Lunine  Jean-Pierre Lebreton  Dennis Matson  Christian Erd  Kim Reh  Patricia Beauchamp  Ralph Lorenz  Hunter Waite  Christophe Sotin  Leonid Gurvits  Mathieu Hirtzig 《Earth, Moon, and Planets》2009,105(2-4):135-142

The Titan Saturn System Mission (TSSM) concept is composed of a TSSM orbiter provided by NASA that would carry two Titan in situ elements provided by ESA: the montgolfière and the probe/lake lander. One overarching goal of TSSM is to explore in situ the atmosphere and surface of Titan. The mission has been prioritized as the second Outer Planets Flagship Mission, the first one being the Europa Jupiter System Mission (EJSM). TSSM would launch around 2023–2025 arriving at Saturn 9 years later followed by a 4-year science mission in the Saturn system. Following delivery of the in situ elements to Titan, the TSSM orbiter would explore the Saturn system via a 2-year tour that includes Enceladus and Titan flybys before entering into a dedicated orbit around Titan. The Titan montgolfière aerial vehicle under consideration will circumnavigate Titan at a latitude of ~20° and at altitudes of ~10 km for a minimum of 6 months. The probe/lake lander will descend through Titan’s atmosphere and land on the liquid surface of Kraken Mare (~75° north latitude). As for any planetary space science mission, and based on the Cassini–Huygens experience, Earth-based observations will be synergistic and enable scientific optimization of the return of such a mission. Some specific examples of how this can be achieved (through VLBI and Doppler tracking, continuous monitoring of atmospheric and surface features, and Direct-to-Earth transmission) are described in this paper.  相似文献   

In situ micro‐Raman and X‐ray diffraction study of diamonds and petrology of the new ureilite UAE 001 from the United Arab Emirates     

Dominik C. HEZEL  Leonid DUBROVINSKY  Lutz NASDALA  Jean CAUZID  Alexandre SIMIONOVICI  Marko GELLISSEN  Thorbjörn SCHÖNBECK 《Meteoritics & planetary science》2008,43(7):1127-1136

Abstract— A new olivine‐pigeonite ureilite containing abundant diamonds and graphite was found in the United Arab Emirates. This is the first report of a meteorite in this country. The sample is heavily altered, of medium shock level, and has a total weight of 155 g. Bulk rock, olivine (Fo_79.8–81.8) and pyroxene (En_73.9–75.2, Fs_15.5–16.9, Wo_8.8–9.5) compositions are typical of ureilites. Olivine rims are reduced with Fo increasing up to Fo_96.1–96.8. Metal in these rims is completely altered to Fehydroxide during terrestrial weathering. We studied diamond and graphite using micro‐Raman and in situ synchrotron X‐ray diffraction. The main diamond Raman band (LO = TO mode at ?1332 cm^?1) is broadened when compared to well‐ordered diamond single crystals. Full widths at half maximum (FWHM) values scatter around 7 cm^?1. These values resemble FWHM values obtained from chemical vapor deposition (CVD) diamond. In situ XRD measurements show that diamonds have large grain sizes, up to >5 μm. Some of the graphite measured is compressed graphite. We explore the possibilities of CVD versus impact shock origin of diamonds and conclude that a shock origin is much more plausible. The broadening of the Raman bands might be explained by prolonged shock pressure resulting in a transitional Raman signal between experimentally shock‐produced and natural diamonds.  相似文献   

Se and In minerals in the submarine oxidation zone of a massive sulfide orebody of the molodezhnoe copper–zinc massive sulfide deposit,Southern Urals     

N. R. Ayupova  V. V. Maslennikov  V. A. Kotlyarov  S. P. Maslennikova  L. V. Danyushevsky  R. Large 《Doklady Earth Sciences》2017,473(1):318-322

For the first time, extremely high Se and In contents were determined for the pinches of massive sulfide orebodies that are composed of small-clastic layered sulfide sediments transformed during submarine supergenesis. Se (clausthalite and naumannite) and In (roquesite) minerals were found. Hydrothermal chalcopyrite, a significant amount of which is present in the clasts of paleohydrothermal black smoker chimneys, was the source of Se. Most of the amount of In was contributed during dissolution of clasts of hydrothermal sphalerite, which is unstable in the submarine oxidation zone in the presence of oxidized pyrite.  相似文献   

Geochemistry of zircons from basic rocks of the Korosten anorthosite-mangerite-charnockite-granite complex,north-western region of the Ukrainian Shield     

Shumlyanskyy  Leonid  Belousova  Elena  Petrenko  Oksana 《Mineralogy and Petrology》2017,111(4):459-466

Mineralogy and Petrology - The concentrations of 26 trace elements have been determined by laser ablation ICP-MS in zircons from four samples of basic rocks of the Korosten...  相似文献   

外贝加尔大骨节病地区水文地球化学特征分析(英文)          下载免费PDF全文

Leonid V. Zamana 《中国地质》2010,37(3):582-586

本文通过对在外贝加尔大骨节病区水文地球化学研究结果表明,该地区天然水呈现出高浓度的磷(高达3.5mg/L),同时,锰、硅、铅等元素也呈现出高浓度的地球化学特征。分析水文地球化学数据,认为大骨节病可能与生物地球化学性质的多种因素有关系。进一步研究大骨节病的成因机制需要新的可靠的环境地球化学数据。  相似文献   

Mineral equilibria in mantle-derived rocks     

Leonid Perchuk  Tibor Gasparik   《Lithos》2002,60(3-4):vii

  相似文献   

Numerical modeling of EM fields over local anomalies with a vertical axis of symmetry     

Michael S. Zhdanov  Vjacheslav V. Spichak  Leonid Yu. Zaslavsky 《Physics of the Earth and Planetary Interiors》1990,60(1-4):53-61

A method for numerical modeling of quasi-stationary electromagnetic fields in axially symmetric media is proposed. It is based on the direct finite-element method and the use of special basis functions. Assuming cylindrical coordinates r, φ, z, the three-dimensional solution is presented as a superposition of fields with the azimuthal dependence exp(inφ). For each case this results in a system of two equations of elliptical type in two scalar functions in the (r, z) plane.

The discretization leads to the conservative nine-points difference scheme. The system of linear equations is solved by means of the LU-decomposition technique, the band structure of the matrix being taken into account.

The program is tested using analytical results (DC asymptote) for a near-surface inhomogeneity. Comparison also is made with 2D results (H-polarization) for the model of a local well conducting inclusion in a three-layered Earth.  相似文献   

A Set of Far East Magmatic Rock Reference Samples: DV     

Leonid A. BERKOVITS  Alexander K. PARSHIN 《Geostandards and Geoanalytical Research》1991,15(1):67-76

  相似文献   

Coexistence of two distinct mantle sources during formation of ophiolites: a case study of primitive pillow-lavas from the lowest part of the volcanic section of the Troodos Ophiolite, Cyprus   总被引：3，自引：0，他引：3  

M. V. Portnyagin  L. V. Danyushevsky  V. S. Kamenetsky 《Contributions to Mineralogy and Petrology》1997,128(2-3):287-301

We present a detailed mineralogical, petrological and melt inclusion study of unusually fresh, primitive olivine + clinopyroxene phyric Lower Pillow Lavas (LPL) found near Analiondas village in the northeastern part of the Troodos ophiolite (Cyprus). Olivine phenocrysts in these primitive LPL show a wide compositional range (Fo_82–92) and have higher CaO contents than those from the Upper Pillow Lavas (UPL). Cr-spinel inclusions in olivine are significantly less Cr-rich (Cr/Cr + Al = 28–67 mol%) compared to those from the UPL (Cr# = 70–80). These features reflect differences in melt compositions between primitive LPL and the UPL, namely higher CaO and Al₂O₃ and lower FeO* compared to the UPL at a given MgO. LPL parental melts (in equilibrium with Fo₉₂) had ∼10.5 wt% MgO and crystallization temperatures ∼1210 °C, which are significantly lower than those previously published for the UPL (14–15 wt% MgO and ∼1300 °C for Fo₉₂). The fractionation path of LPL parental melts is also different from that of the UPL. It is characterized initially by olivine + clinopyroxene cotectic crystallization joined by plagioclase at ∼9 wt% MgO, whereas UPL parental melts experienced a substantial interval of olivine-only crystallization. Primitive LPL melts were formed from a mantle source which was more fertile than that of tholeiites from well-developed intra-oceanic arcs, but broadly similar in its fertility to that of Mid-Ocean Ridge Basalt (MORB) and Back Arc Basin Basalts (BABB). The higher degrees of melting during formation of the LPL primary melts compared to average MORB were caused by the presence of subduction-related components (H₂O). Our new data on the LPL coupled with existing data for the UPL support the existing idea that the LPL and UPL primary melts originated from distinct mantle sources, which cannot be related by progressive source depletion. Temperature differences between these sources (∼150 °C), their position in the mantle (∼10 kbar for the colder LPL source vs 15–18 kbar for the UPL source), and temporal succession of Troodos volcanism, all cannot be reconciled in the framework of existing models of mantle wedge processes, thermal structure and evolution, if a single mantle source is invoked. Possible tectonic settings for the origin of the Troodos ophiolite (forearc regions of intra-oceanic island arc, propagation of backarc spreading into arc lithosphere) are discussed. Received: 20 May 1996 / Accepted: 25 March 1997  相似文献   

Geochemical and isotopic signatures of magmatic products in the MAR rift valley at 12°49′–17°23′ N and 29°59′–33°41′ N: Evidence of Two contrasting sources of the parental melts     

S. A. Silantyev  L. V. Danyushevsky  A. A. Plechova  L. Dosso  B. A. Bazylev  V. E. Bel’tenev 《Petrology》2008,16(1):36-62

Data presented in the paper suggest significant differences between the thermodynamic conditions under which magmatic complexes were formed in MAR at 29°–34° N and 12°–18° N. The melts occurring at 29°–34° N were derived by the melting of a mantle source with a homogeneous distribution of volatile components and arrived at the surface without significant fractionation, likely, due to their rapid ascent. The MAR segments between 12° and 18° N combine contrasting geodynamic environments of magmatism, which predetermined the development of a large plume region with the widespread mixing of the melting products of geochemically distinct mantle sources. At the same time, this region is characterized by conditions favorable for the origin of localized zones of anomalous plume magmatism. These sporadic magmatic sources were spatially restricted to MAR fragments with the Hess crust, whose compositional and mechanical properties were, perhaps, favorable for the focusing and localization of plume magmatism. The plume source between 12° and 18°N beneath MAR may be geochemically heterogeneous.  相似文献