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11.
Skublov S. G. Marin Yu. B. Galankina O. L. Simakin S. G. Myskova T. M. Astaf’ev B. Yu. 《Doklady Earth Sciences》2011,441(2):1724-1731
Zircons with an anomalously high content of Y and REEs in rims were first found in rocks of the Baltic shield (in a pegmatite
vein in the Gridino eclogite-bearing melange and in quartz syenites of the North-Karelian greenstone belt); the total content
reaching 17 wt %. The presence of such an amount of nonformula elements is caused by the isomorphic occurrence of them in
zircon and is not associated with microinclusions of accessory minerals. The age of formation of these rims was determined
as the Svecofennian, although the direct dating yields underestimated values of the age, which are void of geological sense. 相似文献
12.
Yatsenko I. G. Galankina O. L. Marin Yu. B. Skublov S. G. 《Doklady Earth Sciences》2021,500(2):833-837
Doklady Earth Sciences - A study of specific aggregates of corundum from kimberlite and lamproite of the Ukrainian Shield has been carried out. The presence of unusual segregations of oxides,... 相似文献
13.
S. B. Lobach-Zhuchenko V. V. Balaganskii N. G. Berezhnaya S. A. Sergeev O. L. Galankina A. V. Yurchenko E. S. Bogomolov S. L. Presnyakov 《Doklady Earth Sciences》2012,442(2):202-206
The SIMS U-Pb isotopic age of zircons from enderbite gneisses and their metaorthopyroxenite xenoliths in the Pobuzhie granulite
complex, Ukrainian Shield (48°13′57.3″ N and 29°59′21.5″ E, WGS84 system), was determined. The chemical compositions of these
rocks and composing minerals were studied. Enderbite gneisses contain quartz, antiperthite plagioclase, K-feldspar, clinoenstatite,
diopside, amphibole, and a small amount of biotite; accessory minerals are ilmenite and apatite. The age of zircon from enderbite
gneiss is estimated at about 3.15 Ga. Metaorthopyroxenites are composed of orthopyroxene, clinopyroxene, phlogopite (up to
6% TiO2), and plagioclase. The age of magmatic zircons from metaorthopyroxenite determined by the upper intercept of the discordia
with the concordia is 3485 ± 33 Ma (MSVD = 1.6), and the age of metamorphic zircons is 2742 ± 22 Ma (MSVD = 0.22). Hence,
the enderbite gneisses studied pertain to a young group of enderbites in the Pobuzhie granulite complex, while the age of
metaorthopyroxenites from xenoliths in these rocks is similar to that of ancient Pobuzhie enderbites and pyroxenites of the
Novopavlovsk complex in the Azov Region. 相似文献