NEW DATA ON THE AGE OF LAMPROITE-LAMPROPHYRE MAGMATISM IN THE URALS

Abstract

Several occurrences of lamproites on the eastern slope of the Urals are objects of our investigation. The lamproite occurrence situated in the central and eastern part of the Paleozoic Magnitogorsk island-arc system at a few tens of kilometers northeast from Magnitogorsk was described. These lamproites make up a petrogenetic series with lamprophyres (monchiquite, camptonite, minette, and kersantite) identified as the Kalymbai Complex. The second lamproite occurrence (Pervomaiskii area) is located in the eastern part of the East Ural Uplift 40 km south of Chelyabinsk near Pervomaiskii Settlement. This area includes a number of pipe-shaped magnetic anomalies, as well as diatremes and dikes that crosscut the Devonian rocks. In addition, we previously studied the lamproite occurrence near Skalistyi Settlement 25 km west of the town of Troitsk in the Transural region, where lamproite dikes crosscut adamellites of the Lower Sanarka pluton.