Localization of Mesozoic Ore Fields and New Possibilities of Their Prediction: Evidence from Central Aldan

摘要

It has been established that the localization of giant deposits is primarily controlled by intersections of global orthogonal as well as diagonal lineaments. Central Aldan is confined to the junction of the sublatitudi-nal dome of the Aldan Shield, sublongitudinal Yakokutsk Trough, and diagonal lineaments. The study region is located 50-100 km northeast of the central part of the giant Olekma-Timpton ring structure (500-550 km across) identified by Yushmanov. The present work shows the role of ring structures in the localization of ore fields associated with the subsurface central-type morphostructures (CMS) formed during the Mesozoic-Cenozoic tectonomagmatic activation of the Aldan Shield. The Archean-Proterozoic crystalline basement of the Aldan Shield and Central Aldan is mainly overlain by Vendian-Lower Cambrian sedimentary carbonate deposits (500-600 m thick). Lower-Middle Jurassic sandy-clayey molasses up to 500 m thick are found in individual depressions. The study region presents a vivid example of the Mesozoic-Cenozoic tectonomag-matic activation of ancient shields. This region experienced the most intense reworking in the Aldan Shield.