STAGES OF LATE HOLOCENE GULLY DEVELOPMENT IN THE CENTRAL RUSSIAN PLAIN
摘要
Two gullies located in the Protva River basin (central part of European Russia, 100 km southwest of Moscow) were studied to investigate the history of their development during Late Holocene. This case study included detailed topographic and geomorphologic surveys, geological cross-sections, and radiocarbon dating of organic matter in gully sediments. For both gullies, incision of the long profile occurred for most of the Holocene, as indicated by the limited presence of infill sediment. However, interruptions of incisions occurred in both gullies during the last ～3.5 ka (the Chugunkin gully) or ～2.0 ka (the Uzkiy gully), as evident from stratigraphic interpretation of the sediment record. Periods of surface stabilization are represented by buried soil horizons, whereas relatively thick sediment layers suggest periods of predominant aggradation. Similarities and differences in discovered sequences of erosion and accumulation stages for the two gullies point out the importance of distinguishing between local and regional controls. Evidence of the role of internal system behavior and self-development in the gully long-term evolution is clear from asynchronous response of different parts of gullies. In recent times (～500 years), active agricultural development of the study territory resulted in accelerated incisions, followed by deposition of catchment-derived material. The latter was limited to the upper parts of the gullies, while incisions have continued in the middle and lower parts. The impact of human activities (～500 years) has been very limited. This suggests that within the forest zone of the Russian Plain many gullies which were earlier attributed to anthropogenic factors are, in reality, due to natural phenomena.