Age of migmatites in the Stanovoi Complex, east Siberia: Results of zircon dating by the SHRIMP II U-Pb method

Permian age of orogenic thickening and crustal melting in the Garm Block, South Tien Shan, Tajikistan

“…In particular low Th/U ratios were reported for overgrown rims of zircon grains in migmatite leucosomes (e.g. Glebovitsky et al, 2008;Shengyao et al, 2015).…”

U-Pb age of autochthonous paleoproterozoic charnockite in the Aldan Shield

“…The Sm-Nd systematics of granitoids resulted in the following data: a very ancient continen tal crust (at least 3.5 Ga) covered the Aldan Shield in the western part of the Aldan areal within the Nimnyr block; the infracrustal tonalite-trondhjemite complex is about 3.3-3.4 Ga in age [3]. The ancient metamor phism of the amphibolite facies (3.25 Ga [4]) was accompanied by granitization and complex formation of nebulite and anatectic superpotassium granite. Their melting resulted in development of Paleoproterozoic diatectite (2.45 Ga) correlated to high K subalkali granite of the Olekma granite-greenstone area [5].…”

“…The first stage covering the interval of 2430-2450 Ma was synchronous with diatectite formed on the basis of the most ancient high K nebulite under the amphibo lite facies [4] and with allochthonous high K subalkali granites of the Olekma granite-greenstone area [5,14]. The second stage corresponds to the time interval of 1900-1960 Ma, when late autochthonous and parau tochthonous charnockite was formed under the gran ulite facies conditions, while allochthonous granites and charnockites appeared in the central part of the granulite areal [15].…”