[en] Dongfengshan gold deposit is occurred in hornstone of Dongfengshan group under iron-bearing stratum. Ore-bearing stratum contain richly pyrrhotite, pyrite, spessartine and dannemorite. Additionally, there are smaller arsenopyrite and cobaltite. The δ³⁴S values of pyrrhotite and pyrite are -1.54%∼0.98% and -0.27%∼0.61%, respectively. Sulfur of sulfide occurrence mainly from plutonic source. The δ¹⁸O values of different rocks and minerals show following: marble 1.31%∼2.39%, magnetite 0.41%∼1.05%, quarts 1.37%∼2.09%, grunerite 1.09%∼1.68%, garnet 0.99%∼1.75%. These δ¹⁸O values reflect thermal contact metamorphic character of gold deposit. The δ¹⁸O values of the Paleozoic granite obviously are of two groups: one is terrene granite in southern ore area, its δ¹⁸O values are 0.87%∼1.14%; the other is drill hole plutonic granite in northern ore area, its δ¹⁸O values are 0.05%∼0.11%. The granite from drill hole was strongly sericitized. Dongfengshan group was formed in early Proterozoic. Dongfengshan gold deposit is a high temperature thermal contact metamorphic syngenetic deposit

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[en] Isotopic (Sr, Nd)-geochemical studies of the composition of sources of intraplate magmatism in different areas of the Northern Asia were carried out to study the composition and structure of anomalous mantle under the Northern Asia and to determine the processes in its depths occurring in the late Paleozoic early Mesozoic. Geochemical data permitted ascertaining the similarity of the melt sources composition for all the regions studied. Average ¹⁴⁷Sm/¹⁴⁴Nd ratio in the mantle was estimated as 0.18, which permitted ascertaining the age of its enrichment by lithophylic element as 1.3-1.5 bln. year

No abstract available

No abstract available

[en] The first isotope-geochronological data obtained by the K-Ar method for neogene-quaternary rocks in Gegama neovolcanic region located on the territory of Republic of Armenia are presented. Based on the results obtained summary duration of the neomagmatism period of the Gegama plateau (less than 6 mln. years) was ascertained and the time periods of the three stages of magmatic activity, their ranges from 5.7-4.6 mln. years, ∼2.5 mln. years and 700 - <100 thousand years ago, were estimated. The fourth stage includes 4 main stages of volcanic activity, the last of them occurring in Late Neopleistocene and, possibly, Holocene

[en] Petrographic features and geochemical traits accord cumulate status to the rocks and they do not represent melt compositions. Parental melt REE concentrations are calculated by utilising exploratory geochemical inversion techniques. The calculated parental liquids display enriched LREE and flat HREE trends. The variation in the concentrations of REE calculated from different cumulate rocks represents progressive evolution of a parental magma by fractional crystallization. Petrogenetic modelling suggests that the parental liquids are derived by 5 to 10% melting of an LREE enriched komatiite/tholeiite source in the deep crust. This source could be an underplated Late Archaean crust and this deep crustal melting might have been induced by the heat released from a mantle plume

[en] The content of calcareous nannofossils (remnants of microscopic planktonic algae) have been documented in numerous sediment cores from the Norwegian and Greenland Seas and in ODP Hole 704A from the subantarctic South Atlantic. Worldwide species extinctions, inceptions and distinct abundance variations have been used to correlate and date the studied cores, which comprise the last 500,000 years. The biostratigraphy has been correlated to oxygen isotope stratigraphy which shows that intervals rich in nannofossils represent interglacial time periods. The calcareous nannofossils indicate that during the time period studied, climatic fluctuations were similar in character and timing in both the subarctic and the subantarctic South Atlantic. Abundance patterns of warm water species suggest that surface waters were warmer than today only during oxygen isotope substage 5e (the last interglacial). The environment was interglacial also during isotope stages 9, 11, and 13, while stages 3 and 8 may have been characterized by intermediate glacial conditions. A significantly colder environment than at present prevailed in isotope stages 2, 4, 6, 10 and 12. Isotope stage 7 appears to have been fully interglacial in the subantarctic South Atlantic, but intermediate glacial in the Norwegian sea

[en] Ice cores from New Zealand and the Antarctic margin provide an excellent means of addressing the lack of longer-term climate observations in the Southern Hemisphere with near instrumental quality. Ice core records provide an annual-scale, 'instrumental-quality' baseline of atmospheric temperature and circulation changes back many thousands of years. (author).

[en] Ice cores from New Zealand and the Antarctic margin provide an excellent means of addressing the lack of longer-term climate observations in the Southern Hemisphere with near instrumental quality. Ice core records provide an annual-scale, 'instrumental-quality' baseline of atmospheric temperature and circulation changes back many thousands of years. (author).