Sinian Complex

a complex of rocks of the Upper Precam-brian, consisting of quartzites, shales, and andesitic lavas in the lower part and mainly of limestones and dolomites with stromatolites in the upper part. It is 8,000 m thick. In the basin of the Yangtze River, the complex contains a characteristic array of the glacial conglomerates known as tillites. Ore deposits associated with the Sinian complex include manganese ores, in Southeast China, and iron ores, in, for example, the province of Liaoning and the autonomous region of Inner Mongolia.

The Sinian complex was first identified in 1882 by the German geologist F. von Richthofen in China. It was studied in detail in 1922 by the American geologist A. Grabau, who regarded it as a separate geological system. It corresponds to most of the Riphean system. Analogues of the Lower Riphean, however, have not been identified in the Sinian complex. [23–1245–]