Chronology of Hydrothermal Activity Within the Yubileynoye Ore Field (Mid-Atlantic Ridge, 20°08′ N)

This paper reports on the integrated geochronological and geochemical methods used in studying the ore deposits and metalliferous sediments of the Yubileinoye field. This study gives the opportunity to carry out cross dating of hydrothermal deposits, including the ²³⁰Th/U dating of sulfides, the ²³⁰Th, ¹⁴C dating, and foraminiferal analysis of the sediments, and, on this basis, to reconstruct hydrothermal activity over time. It was established that the ores started forming about 100 000–123 000 years ago and were renewed 4–5 times with a frequency of 10–20 ka. As a result, the complex of pyrite-marcasite, chalcopyrite and sphalerite ores and the associated metal-bearing and ore-bearing sediments with consistent geochemical specialization were formed. The integrated geochronological and geochemical studies of the ores and sediments allow us to obtain detailed data on evolution of the hydrothermal ore-formation not only in the certain areas but also for the entire Mid-Atlantic Ridge.     

Geological Position,Age, and Sources of the Tallai Gabbro–Diorite–Plagiogranite Pluton (Middle Vitim Highland)

Doklady Earth Sciences - The results of geochronological study (U–Pb SHRIMP-II) of zircons from granodiorites and plagiogranites of the main phase of the Tallai pluton of the...     

Mineral Phases of the Pd–Bi–Se System in the Ores at the Chudnoe Au–Pd Deposit (Subpolar Urals,Russia)

Doklady Earth Sciences - In the Pd–Bi–Se system, the only known mineral containing all three elements is padmaite PdBiSe. Three compounds with different element ratios have been found...