Late Quaternary climatic and tectonic mechanisms driving river terrace development in an area of mountain uplift: A case study in the Langshan area, Inner Mongolia, northern China

The Langshan Range is located in the western Yin Mountain orogenic belts and the western Hetao fault-depression zone in Inner Mongolia, northern China. This area is on the northwestern margin of the East Asian monsoon region. The fluvial terraces in the transverse drainage of the Langshan Range represent a primary geomorphic response to local tectonic uplift and climatic changes. The terrace evolution was reconstructed using a combination of optically stimulated luminescence (OSL) dating and terrace tread measurements. The terraces, designated T4 through T1, were abandoned at about 58.00, 46.25, 32.19, and 15.79 ka BP, respectively. Their aggradation occurred primarily during cold periods of the last glacial stage, and incision occurred primarily during shifts from cold to warm climate stages. Geomorphic analysis showed the terrace heights were controlled by the tectonic uplift in the area. Differences in river incision rates and terrace geomorphic features indicate that the uplift of the Langshan Range included a component of tilting north to south during the period of 58.00–41.28 ka BP, whereas the uplift of the Langshan area tended to be equal on a regional scale after 32.19 ka BP.