Инд. авторы: | Madyukov I.A., Chupin V.P., Kuzmin D.V. |
Заглавие: | Genesis of scapolite from granulites (lower-crustal xenoliths from the Pamir diatremes): Results of study of melt inclusions |
Библ. ссылка: | Madyukov I.A., Chupin V.P., Kuzmin D.V. Genesis of scapolite from granulites (lower-crustal xenoliths from the Pamir diatremes): Results of study of melt inclusions // Russian Geology and Geophysics. - 2011. - Vol.52. - Iss. 11. - P.1319-1333. - ISSN 1068-7971. - EISSN 1878-030X. |
Внешние системы: | DOI: 10.1016/j.rgg.2011.10.005; SCOPUS: 2-s2.0-80455149992; |
Реферат: | eng: The results of mineralogical and thermobarogeochemical studies of lower-crustal xenolith of scapolite-bearing granulites from the fergusite-porphyry diatremes pipes in Southeastern Pamir (Tajikistan) are presented. All minerals (including garnet, clinopyroxene, and scapolite) of these granulites contain primary melt inclusions, which were studied using thermometric and microprobe methods (EPMA, SIMS, Raman spectroscopy). We have established that their compositions correspond to acid (from rhyodacites to rhyolites), essentially potassic melts of normal and high alkalinity with H2O ≤ 4 wt.%, Cl ≤ 0.8 wt.%, and CO2 ~ 1 wt.%. The melts are depleted in HREE and have high Th/U ratios (7.7-9.4). Study of melt inclusions using mineralogical thermobarometers showed that the scapolite-bearing granulite crystallized at ~1000 °C and ~15 kbar. This rock resulted, most likely, from the incongruent melting of carbonate-bearing biotite-quartz-plagioclase substrate in the lower crust, which was accompanied by the crystallization of garnet, clinopyroxene, sphene, plagioclase, and scapolite trapping microportions of acid melts as inclusions. The minerals crystallized not from melt but in its presence. High-Ca scapolite (Me67-69) crystallized instead of plagioclase when the melts reached high contents of CO2 (~1 wt.%) and Cl (≤0.8 wt.%) in the presence of CO2-rich fluid. © 2011.
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Ключевые слова: | Pamirs; xenolith; scapolite; porphyry; plagioclase; mineralogy; melting; melt inclusion; lower crust; granulite; geochemistry; diatreme; crystallization; chlorine; carbon dioxide; alkalinity; Scapolite; Pamir; Melt inclusions; Lower crust; Incongruent melting; Granulite xenolith; |
Издано: | 2011 |
Физ. характеристика: | с.1319-1333 |