the Sinian Shield, an ancient platform occupying the lower portion of the Huang Ho basin and the Korean Peninsula, as well as the floor of much of the Yellow Sea.
In the west, the continuation of the platform can be traced in the form of a narrow wedge along Inner Mongolia. The eastern part of the platform, which takes in Korea and East China, has a folded crystalline base of Precambrian (Proterozoic and Archaean) age. The basement, which emerges on the surface in the form of uplifts within Korea, the Liaotung Peninsula, and Shansi (to the west of Peking), is composed of metamorphic rock (gneisses, migmatites, crystalline schists, and amphibolites) and granites. Major deposits of ferruginous quartzites are related to the Anshan Series (Lower Proterozoic). The western, narrowed part of the platform is younger, and its base corresponds to the Baikalian folded system. The platform’s basement is overlaid with the rock of the sedimentary mantle (Proterozoic, Lower and Upper Paleozoic, in places Triassic and Jurassic), while the lower part of the sedimentary complex is composed of deposits from the Sinian system (the age of which corresponds to the Riphean complex of the USSR). Coal deposits are concentrated in Carboniferous, Permian, and Jurassic deposits, and bauxites in Permian deposits (Shantung Province).
P. N. KROPTKIN