Typomorphism and parasteresis of Yushkinite, the Pai-Khoi anticlinorium

Yushkinite found in quartz-calcite hydrothermal veins in the Pai-Khoi Anticlunorium (the middle reaches of the Silova-Yakha River) is associated with fluorite, sphalerite, and sulvanite and occurs as fine-lamellar aggregates. The mineral is pinkish purple, with perfect cleavage parallel to (0001). The Moh hardness is lower than 1. In reflected light, yushkinite is anisotropic, with strong bireflectance. It is uniaxial and optically negative. Yushkinite was discovered and approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association, in 1983. Twenty years later, reexamination of yushkinite and associated minerals gave rise to the discovery of a new carbonate phase and specification of the physical properties and chemical composition of yushkinite.     

Rare earth and strontium aluminophosphates from the Vol-Vym Ridge of the Middle Timan

The genesis and primary source of the well-known diamond placers in the Umba-Pizhma region of Timan still remain unclear. Diamonds are not associated with the typical index minerals of the ultramafic assemblage. Epigenetic rare earth aluminophosphates (florencite, goyazite, etc.) occur as individual grains or supergene coatings on the diamonds’ surfaces without any relation to the primary diamond assemblage. They are often observed over syngenetic metal films on the diamond crystals’ surfaces. These minerals also occur as secondary inclusions in pores of leucoxene from the Pizhma deposit, as well as in Brazilian carbonados. Owing to their typomorphic features, aluminophosphates may be used as the secondary index minerals of the diamonds.     

The Oxygen Isotope Composition of Late Pleistocene and Holocene Ice Wedges of Kotelny Island

The aim of the work was to perform paleotemperature reconstructions for the Late Pleistocene and Holocene of Kotelny Island according to oxygen isotope analysis of syngenetic ice wedges. Variations of δ¹⁸O in the Late Pleistocene ice wedges formed on Kotelny Island are significant, exceeding 8‰ (from –30‰ to –22.9‰), while they are insignificant at –1.5‰ (from –23.1‰ to –21.6‰) for those in the Holocene. Reconstructions showed that the mean January temperature in the Late Pleistocene changed over 8 to 13°C. The mean annual temperature of frozen soils was about –19 or –20°C in the Late Pleistocene, and about –13 to –15°C in the Holocene, while the current temperature is about –14°C.

     

Strong Earthquakes on the Southern Slope of the Kungei Ala-Too Range,Northern Tien Shan,and Their Structural Position in the Earth’s Crust

Izvestiya, Atmospheric and Oceanic Physics - The morphostructures and paleoseismicity of the southern slope of the Kungei Ala-Too Range (Northern Tien Shan) have been studied. It has been found...     

俄罗斯地台北缘和东北缘的曲面金刚石(英文)

曲面金刚石广泛产于金刚石砂矿和含金刚石的金伯利岩管及钾镁煌斑岩中。曲面金刚石是一种特殊的晶体类型 ,它与平坦面金刚石相比 ,不仅晶习不同 ,曲面金刚石常呈四六面体 ,而平坦面金刚石常呈八面体 ,而且它更坚实 ,更具宝石价值。热力学计算和实验表明 ,八面体金刚石比立方八面体和立方体金刚石的形成温度高 ,意味着曲面金刚石形成深度较浅 ,可能在石墨 -金刚石稳定区的边界上。目前对曲面金刚石是生长形还是由平坦面金刚石熔蚀而成尚有不同见解。文章对俄罗斯地台北缘和东北缘的曲面金刚石进行了综合研究。经切割抛光 ,用 X射线形貌法、阴极发光法和普通光学法进行了结构研究 ,还对金刚石进行了光学荧光、 X射线荧光 ( T=77～ 2 90 K)、ESR电子自旋共振、可见光区的吸收谱等研究。用光学测角仪和扫描电镜查明 ,研究区的金刚石中四六面体单形占 60 %～ 80 %、 { 0 65} +{ 365} +{ 1 1 1 }聚形占 8%～35%、平坦面八面体占 0～ 8%且无菱形十二面体。研究发现金刚石表面覆有成分不同的薄膜 ,厚约 0 .1～ 1 μm,其成分有 2 9种之多。表明天然金刚石是在多种金属和碳的熔体中结晶的 ,乌拉尔 -巴西型金刚石的曲面晶为生长晶而非熔蚀晶。在罗蒙诺索夫金伯利岩管中获取的金刚石表面附有超基性岩的原生矿物组合?