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Kimberlite melts rich in alkali chlorides and carbonates: A potent metasomatic agent in the mantleстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 6 декабря 2018 г.
- Авторы: Kamenetsky Maya B., Sobolev Alexander V., Kamenetsky Vadim S., Maas Roland, Danyushevsky Leonid V., Thomas Rainer, Pokhilenko Nikolai P., Sobolev Nikolai V.
- Журнал: Geology
- Том: 32
- Номер: 10
- Год издания: 2004
- Издательство: Geological Society of America
- Местоположение издательства: United States
- Первая страница: 845
- Последняя страница: 848
- DOI: 10.1130/g20821.1
- Аннотация: Kimberlite magmas, as the deepest probe into Earth's mantle (>150 km), can supply unique information about volatile components (hydrogen, carbon, chlorine, sulfur) in mantle-derived melts and fluids. All known kimberlite rocks are not suitable for studies of mantle volatiles because of their pervasive postmagmatic alteration; however, this study discusses an exceptionally fresh group I kimberlites (<0.5 wt% H 2O) from the Udachnaya-East diamondiferous pipe in Siberia. Kimberlite groundmass, in addition to euhedral olivine and calcite, is extremely enriched (at least 8 wt%) in water-soluble alkali chlorides, alkali carbonates, and sulfates (ratio 5:3:1), and often shows immiscibility textures. A primary magmatic origin of alkali chlorides and alkali carbonates is confirmed by the study of strontium isotopes in the water- and dilute acid-leachates of the groundmass ( 87Sr/86Sr = 0.7069 and 0.7050) that contrast with much more radiogenic isotope composition of the Cambrian platform sedimentary rocks and the Udachnaya-East mine-site brines. Melt inclusions in groundmass olivine, composed of halite, sylvite, alkali-Ca carbonates, phlogopite, olivine, and CO2 fluid, were used to determine the composition and evolution of the kimberlite melt prior to emplacement. Melt inclusions show immiscibility between chloride and carbonate liquids at <600 °C in heating stage experiments. The chloride and carbonate enrichment in the kimberlite parental magma suggests the presence of a powerful agent for chemical modifications (metasomatism) in the mantle and crust.
- Добавил в систему: Каменецкий Вадим Семенович