Volcanic Tuffs, Red- and Usual-Colored Clayey Rocks in Upper Riphean–Vendian Deposits in the Middle and Southern Urals: Comparison of Lithochemical Characteristics

Abstract

In the lower part of Upper Vendian deposits on the East European Platform, packs of chocolate-brown clayey rocks/tuff-argillites containing intercalations of volcanic tuffs (products of acid volcanism) are widespread. Upper Riphean–Vendian sections on the western slope of the Middle and Southern Urals include packs of the red-colored clayey rocks. Among them, volcanic tuffs (clay-type rocks) with the atypical anomalous coloration (light gray with a pinkish, cream, greenish or steel tint, light brown with a beige tint, and others) were found in the early 2000s. The purpose of the present work is to compare the lithogeochemical characteristics of volcanic ash tuffs, red- and usual-colored clayey rocks at different Upper Riphean–Vendian stratigraphic levels in the Middle and Southern Urals and to determine signs of the probable pyroclastic/tuffogenic material admixture in the red-colored clayey rocks.