Preliminary Study on Loess Doline
Zhang Shiwu et al. (Geologic Disaster Institute of Gansu Provincial Academy of Sciences, Lanzhou)
Loess doline, the result of collapsing loess in lowland subject to longterm mechanical subsurface corrosion, can be divided into dish-like loess depression, loess sinkhole and loess sink well. Loess dolines distribute ex-tensively in the Loess Plateau.,Loess sinkholes and loess sinkwells are well developed in collapsing loess area with annual rainfall of about 450mm, and comparatively less developed on edges of loess tableland and high terrace. Loess dolines distribute along ravines and small gullies in the ridge area in form of series of beads. Loess dolines on slope of mounds in the rolling area are mainly loess sinkholes and dish-like loess depressions count the second. Loess sinkholes and loess sinkwells are also comparatively well developed on loess platform and gully head. Loess dolines play an important role in the developing process of landslide and debris flow and are the important channels of ground water recharge in the loess area.