GLACIAL AND GLACIFLUVIAL AMBER-BEARING DEPOSITS OF UKRAINE

Finds of amber in the Lower Neopleistocene deposits of Ukraine have not been identified yet. But conditions for forming amber placers in the Early Neopleistocene existed in Volyn Polesye. The most important of these conditions were: 1) territorial proximity of primary Paleogene placers of amber, 2) block heterogeneity, 3) differentiated character of neotectonic movements, 4) denudation processes in the Neogene, 5) exarative-accumulative activity of Narev and Oka glaciations. Potentially amber-bearing here are the rills of glacial ploughing, allocation of which is controlled by active faults.

Middle Neopleistocene amber-bearing deposits were formed due to the exarative-accumulative activity of the Dnieper glacier, which influenced the paleorelief in the most degree. The primary deposits of Late Eocene-Early Oligocene age were destroyed by the separate tongues of the Dnieper glacier, with amber, as a result, being included into morainic deposits. The mechanism of amber accumulation in morainic deposits has been considered with Rafalovka glacial ridge taken as a model. The obtained data allowed making a supposition that terminal-morainic formations in the interfluves of the Styr-Stohid and Stohid-Tur'ya had similar to Rafalovka ridge structure and character of amber occurrence in morainic deposits.

The most favorable conditions for the accumulation of amber in glacifluvial deposits existed in the Styr-Goryn interfluve. Forming glacifluvial cover and including amber from the underlying Upper Eocene-Lower Oligocene sediments occurred due to the influence of Styr lobe of the Dnieper glacier. Placers of amber are confined to the glacifluvial deltas, which occupy the lowest areas of Upper Cretaceous and Paleogene surface.

The obtained results allowed distinguishing areas with maximum possible concentrations of amber in morainic, glacifluvial and glacio-lacustrine deposits: 1) morainic and outwash plains that are characterized by relatively more intensive development of accumulative processes and which have been formed in the limits of blocks which underwent slow elevation and subsiding; 2) outwash plains that are characterized by intensive development of accumulative processes and which have been formed in the limits of blocks which underwent relative subsiding.