Paleochannel-controlled earth fissures in Daming, North China Plain and their implication for underground paleogeomorphology

Autor: Haiyu Sun, Hongwei Hu, Feiyong Wang, Baoting Yang, Jianbing Peng, Jishan Xu, Haibo An
Rok vydání: 2019
Předmět:
Zdroj: Geomorphology. 327:523-532
ISSN: 0169-555X
DOI: 10.1016/j.geomorph.2018.11.020
Popis: Earth fissures are a geologic phenomenon that mainly affects the medium with shallow surface soil and mainly developed in the Quaternary sediment cover. In the Yellow River-Qinghe River - Zhanghe River shallow buried paleochannel Band (HQZ-Qh2-II Band) on the North China Plain, 93 earth fissures are developed. Among them, 29 fissures are evolved in the Daming zone in the upper reaches of the paleochannel band. Thus, the zone belongs to a densely grouped fissure area. This study, through a series of field trenching and surveying, revealed that these earth fissures have unique plane distribution rules and profile structure features of short length (several meters to several hundred meters), shallow depth (smaller than 10 m) and good correspondence to Daming paleochannels. These basic characteristics reveal that unlike other tectonic earth fissures, Daming earth fissures are a new and unknown type of fissures, i.e., paleochannel-controlled earth fissures. Theoretical analysis of their features showed that they were formed due to the actions of gravity, primary joint factors and groundwater pumping activities and controlled by ancient river factors including paleochannels, sediments and groundwater. Among them, the process of Mode I can be summed up as “self-gravity action - tensile cracks - surface water scouring - earth fissures”. The process of Mode II is “primary join - surface water infiltration - piping - cave in - earth fissures”. The process of Mode III is “groundwater extraction - aquifer compression - inhomogeneous ground subsidence - earth fissures”. These formation mechanisms of paleochannel-induced earth fissures can be used to predict the fine distribution of shallow buried paleochannels and the overall migration process of the rivers. Thus, this kind of earth fissures is of great significance for understanding the underground paleogeomorphology (buried paleochannel) of the North China Plain and other alluvial plains of the world.
Databáze: OpenAIRE
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