Тип публикации: статья из журнала

Год издания: 2020

Идентификатор DOI: 10.3390/min10040337

Ключевые слова: Aldan shield, Kamafugite, Lamproite, Melt inclusions, Olivine, SCLM, Siberian platform, lamproite; kamafugite; olivine; melt inclusions; Aldan shield; Siberian platform; SCLM

Аннотация: Mesozoic (125-135 Ma) cratonic low-Ti lamproites from the northern part of the Aldan Shield do not conform to typical classification schemes of ultrapotassic anorogenic rocks. Here we investigate their origins by analyzing olivine and olivine-hosted inclusions from the Ryabinoviy pipe, a well preserved lamproite intrusion within thПоказать полностьюe Aldan Shield. Four types of olivine are identified: (1) zoned phenocrysts, (2) high-Mg, high-Ni homogeneous macrocrysts, (3) high-Ca and low-Ni olivine and (4) mantle xenocrysts. Olivine compositions are comparable to those from the Mediterranean Belt lamproites (Olivine-1 and -2), kamafugites (Olivine-3) and leucitites. Homogenized melt inclusions (MIs) within olivine-1 phenocrysts have lamproitic compositions and are similar to the host rocks, whereas kamafugite-like compositions are obtained for melt inclusions within olivine-3. Estimates of redox conditions indicate that “lamproitic” olivine crystallized from anomalously oxidized magma (ΔNNO +3 to +4 log units.). Crystallization of “kamafugitic” olivine occurred under even more oxidized conditions, supported by low V/Sc ratios. We consider high-Ca olivine (3) to be a fingerprint of kamafugite-like magmatism, which also occurred during the Mesozoic and slightly preceded lamproitic magmatism. Our preliminary genetic model suggests that low-temperature, extension-triggered melting of mica- and carbonate-rich veined subcontitental lithospheric mantle (SCLM) generated the kamafugite-like melts. This process exhausted carbonate and affected the silicate assemblage of the veins. Subsequent and more extensive melting of the modified SCLM produced volumetrically larger lamproitic magmas. This newly recognized kamafugitic “fingerprint” further highlights similarities between the Aldan Shield potassic province and the Mediterranean Belt, and provides evidence of an overlap between “orogenic” and “anorogenic” varieties of low-Ti potassic magmatism. Moreover, our study also demonstrates that recycled subduction components are not an essential factor in the petrogenesis of low-Ti lamproites, kamafugites and leucitites. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Журнал: Minerals

Выпуск журнала: Vol. 10, Is. 4

Номера страниц: 337

ISSN журнала: 2075163X

Издатель: MDPI AG

• Chayka I.F. (Sobolev Institute of Geology and Mineralogy Siberian Branch%Russian Academy of Sciences%Novosibirsk%630090%Russian Federation%Institute of Experimental Mineralogy%Russian Academy of Sciences%Chernogolovka%142432%Russian Federation)
• Sobolev A.V. (Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow, Russian Federation, Institut des Sciences de la Terre (ISTerre), Universite de Grenoble Alpes, Grenoble, 38041, France)
• Izokh A.E. (Sobolev Institute of Geology and Mineralogy Siberian Branch%Russian Academy of Sciences%Novosibirsk%630090%Russian Federation%Department of Geology and Geophysics%Novosibirsk State University%Novosibirsk%630090%Russian Federation)
• Batanova V.G. (Institut des Sciences de la Terre (ISTerre), Universite de Grenoble Alpes, Grenoble, 38041, France)
• Krasheninnikov S.P. (Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow, Russian Federation)
• Chervyakovskaya M.V. (Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences, Yekaterinburg, 620016, Russian Federation)
• Kontonikas-Charos A. (School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia)
• Kutyrev A.V. (Institute of Volcanology and Seismology, Far Eastern Branch of the Russian Academy of Sciences, Petropavlovsk-Kamchatsky, 683000, Russian Federation)
• Lobastov B.M. (Institute of Mining, Geology and Geotechnology, Siberian Federal University, Krasnoyarsk, 660041, Russian Federation)
• Chervyakovskiy V.S. (Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences, Yekaterinburg, 620016, Russian Federation)

• Scopus
• Web of Science Core Collection
• Ядро РИНЦ (eLIBRARY.RU)