LA_ICP_MS analysis shows that the inherited zircons are characterized by high concentrations of Y (1121×10 -6), HREE (641×10 -6) and MREE (182×10 -6), and low abundances of U (207×10 -6), Th (171 ×10 -6) and Hf (0.96%).
Ion microprobe U-Pb dating of zircons from the tonalitic gneiss and quartz dioritic orthogneiss yielded statistically distinguishable 206 Pb / 238 U crystallization ages of 58.5±0.7Ma and63.5±0.8Ma ,respectively.
Single zircon U Pb, 40 Ar / 39 Ar,Sm Nd and Rb Sr isochron ages suggest that the greenstone belt was formed 2700—2800 Ma ago. The ages of three types of syntectonic granites associated with the greenstone belt are (2555±35)Ma,(2515±4)Ma and 2505—2400Ma,respectively.
The Bainhalatu suits, however, have strong contrast between LREE and HREE, an important negative Eu abnormality and a single zircon U Pb age of 363Ma, and are typical of high SiO 2, K 2O, Rb and low CaO, FeO, MgO, Co, Sr.
Potentials of Electron Probe Microanalysis in Studying Zircons
Potentials of electron probe microanalysis in determining hafnium, uranium, thorium, lead, niobium, titanium, manganese, iron, chromium, calcium, aluminum, tin, tungsten, yttrium, and lanthanide impurities in zircons have been studied.
Sources of Zircons from Cretaceous and Lower Paleogene Terrigenous Sequences of the Southern Koryak Upland and Western Kamchatka
Age of Detrital Zircons from Sandstones of the Mesozoic Flysch Formation in the South Anyui Suture Zone (Western Chukotka)
This work presents first data on age estimates of detrital zircons from Upper Mesozoic terrigenous sequences of the South Anyui suture zone obtained by the fission-track method.