排序方式： 共有33条查询结果，搜索用时 38 毫秒
1.
R. A. Oktyabrsky A. A. Vrzhosek A. M. Lennikov T. A. Yasnygina S. V. Rasskazov E. Yu. Moskalenko T. A. Velivetskaya 《Russian Journal of Pacific Geology》2008,2(4):325-335
New geochemical data are presented on the magmatic rocks of the Late Jurassic Koksharovka alkaline-ultrabasic massif, which is associated with deposits of vermiculite, apatite, V-bearing titanomagnetite, and placer isoferroplatinum. The REE geochemistry and strontium, oxygen, and carbon isotopic composition of carbonatites and related ijolites and pyroxenites, together with geological observations, point to the magmatic origin of the Koksharovka carbonatites. The origin of associated magmatic rocks is discussed. Trace element modeling of partial melting of mantle sources was conducted to decipher the genesis of the melts of the Koksharovka carbonatites and host titanite-kaersutite pyroxenites. 相似文献
2.
A. M. Kozlovsky V. V. Yarmolyuk V. I. Kovalenko V. M. Savatenkov T. A. Velivetskaya 《Petrology》2007,15(3):240-263
The bimodal association of the Noen and Tost ranges is ascribed to the Gobi-Tien Shan rift zone and was formed 318 Ma ago at the continental margin of the North Asian paleocontinent. It is made up of volcanic series of alternating basalts and peralkaline rhyolites with subordinate trachytes, dike belts, and massifs of peralkaline granites. The association also includes a coeval massif of biotite granites. Based on Al2O3 and FeOtot contents, the peralkaline rhyolites are subdivided into comendites (FeOtot 1.5–5.7 wt %, Al2O3 10.5–15.4 wt %) and pantellerites (FeOtot 5.2–7.5 wt %, Al2O3 9.1–10.2 wt %). The peralkaline salic rocks of the bimodal association were formed by the crystallization differentiation of rift basaltic magmas combined with crustal assimilation. The comendites, pantellerites, and peralkaline granites inherited negative Nb and Ta and positive K and Pb anomalies from basalts. They are also similar to basalts in Nd isotope composition (?Nd(T) = 5.5–7.4) and have nearly mantle oxygen isotope composition (δ18O = 5.9–7.3‰). The most differentiated and least contaminated rocks of the bimodal series of the Noen and Tost ranges are pantellerites. Calculations indicate that the fraction of the residual pantellerite melt was 8% or less of the parental basaltic magma. The comendites were derived from peralkaline salic melts by the assimilation of anatectic crustal melts compositionally similar to biotite granites. The formation of the latter within the Noen and Tost ranges is explained by the specific geodynamic position of the Gobi-Tien Shan rift zone, which was formed near a paleocontinental margin that evolved in an active margin regime shortly before the beginning of rifting. 相似文献
3.
N. A. Goryachev G. N. Gamyanin V. Yu. Prokof’ev N. E. Savva T. A. Velivetskaya A. V. Ignat’ev 《Geology of Ore Deposits》2014,56(5):322-345
This paper is focused on the Early Cretaceous Ag-Bi-Co-sulfoarsenide mineralization atypical of northeastern Asia, which contains diverse Co-Ni sulfoarsenides, Se-bearing Bi sulfotellurites, and Ag-Bi-Pb sulfosalts. The Upper Seymchan ore cluster is located at the boundary between the Paleozoic Omulevka Terrane of carbonate platform and the In’yali-Debin Synclinorium of the Kular-Nera Terrane. These ore-bearing sequences are represented by the Middle Jurassic terrigenous rocks that rest upon the Upper Triassic sandshale rocks of the upper structural stage. The sedimentary rocks are cut through by high-Al granitic plutons and younger granite-porphyry dikes. The orebodies that are superposed on igneous rocks were formed during (1) the quartz-chlorite-tourmaline stage of metasomatic alteration, (2) the main economic tourmaline-chlorite-quartz-sulfoarsenide vein stage, (3) the polysulfide-quartz stage with Ag, Se, Bi minerals, and (4) the postore quartz-calcite stage with fluorite. The epithermal veins of festoon chalcedony-like quartz with Sb-bearing arsenopyrite occupy a special position. In particular orebodies, the chlorite-quartz ore veins dominate at the upper levels, whereas the quartz-tourmaline veins occur at the lower levels. Wall-rock alteration is represented by metasomatic chloritization and tourmalinization up to the formation of monomineralic metasomatic zones. Sulfides and sulfoarsenides are distinguished by anomalous enrichment of sulfur in the light isotope (δ34S = ?12.8 to ?16.7‰) in contrast to the sulfur isotopic composition of Sb-asenopyrite (?1.7‰) from the genetically different epithermal veins. The oxygen isotopic composition of calcite (the third stage) is uniform at all studied deposits and reveals a tendency to updip enrichment in δ18O within a vertical interval of 200 m. Quartz from ore-bearing and epithermal veins has an almost identical δ18O value (±2‰) but differs from quartz at the tin deposits related to granites of the Canyon Complex and enriched in the light isotope in its oxygen isotopic composition. The mineralization in the Upper Seymchan ore cluster, which is genetically linked to the Early Cretaceous calc-alkaline dike suite pertaining to the period of postcollision late orogenic extension, is formed from magmatic fluids diluted with meteoric water (salinity reaches 20 wt % NaCl equiv) at temperatures varying from 400-380°C to 220-150°C and under a pressure of 970 to 60 bar. The direct vertical mineral zoning is expressed in the change of mineral species with depth and in variable compositions and properties of particular minerals. 相似文献
4.
Tarasova Yu. I. Budyak A. E. Goryachev N. A. Ignatiev A. V. Velivetskaya T. A. Blinov A. V. Goryacheva E. M. 《Doklady Earth Sciences》2022,503(1):81-85
Doklady Earth Sciences - The results of studying the isotopic, geochemical, and TEDS properties of various generations of pyrite and pyrrhotite from the Ugakhan deposit, Bodaibo district of Irkutsk... 相似文献
5.
6.
7.
8.
A. V. Ignat’ev A. I. Khanchuk S. V. Vysotskii T. A. Velivetskaya V. I. Levitskii E. N. Terekhov 《Doklady Earth Sciences》2016,469(2):867-869
The first data on the multi-isotope composition of sulfur (32S, 33S, 34S) in samples from the Fennoscandian Shield were obtained by the laser local method. An anomalous concentration of the stable isotope 33S was registered in some samples. Δ33S ranges from–0.45 to +0.24‰, which indicates the mass-independent fractionation of S isotopes and provides evidence for the processes of primarily sedimentary accumulation of sulfides in the Archean oxygen-free atmosphere. 相似文献
9.
R. A. Oktyabr’skii N. V. Vladykin A. M. Lennikov A. A. Vrzhosek T. A. Yasnygina S. V. Rasskazov E. Yu. Moskalenko T. A. Velivetskaya 《Geochemistry International》2010,48(8):778-791
New geochemical data are discussed on the magmatic complexes of the Koksharovka alkaline ultrabasic massif of Late Jurassic
age obtained by the ICP-MS method. Based on the first results on rare earth geochemistry of carbonatites and associating pyroxenites
and geological observations, the magmatic origin of the Koksharovka carbonatites was substantiated, and the problems of formation
of accompanying igneous rocks were considered. 相似文献
10.