Paleogeographic Orientation of the Sino‐Korean Plate Based on Evidence for a Prevailing Silurian Wind Field

Abstract

Abstract The regional geology of southern Inner Mongolia records relationships between an upper Silurian coastline and a small island on what was formerly the continental shelf of the Sino‐Korean Plate (North China Block). In both cases, rocky shorelines are defined by unconformities between strata of Ludlow age in the Xibiehe Formation and underlying igneous rocks of Ordovician age. The paleoisland occurs near Bater Obo about 50 km south of the Chinese‐Mongolian border. The diorite core of this geological inlier is oriented on an axis N 55° E. A simple dichotomy of exposed windward versus sheltered leeward environments accounts for contrasting carbonate facies on the flanks of the paleoisland. Wider corroboration of a prevailing Silurian wind field is supported by evidence from other unconformities about 30 km to the southwest, where a linear paleoshore extends for 15 km on an average bearing of N 60° E. Siliciclastic sandstone derived from a granodiorite source in the Gushan area now sits in close proxi...