Study on the Ice-induced Heaving in Yellow River Delta

Key words: 
• ice /
• heaving /
• genesis

Abstract: A lot of ice induced sedimentary structures are developed on Yellow River delta and one of them is rernarkedly ice induced heaving． Ice-induced heaving has a hill-like shape in appearance and circutar hill-like ones is often seen,and a few of them have long hill-like,irregular platform,tower-colurnn,earth pyramid and volcanic shapes with different sizes ranging from several centimeters(small ones)to a{ew decades of centimeters(1arge oes)and the largest is more than one meter in length,The surfaces of ice-induced heavings are smooth or have fission or pits like crater,and or have a lot of pea-like nodule or root-like structures．Some of ice-induced heavings have dome-like bedding within its interior,and some have complex deformation beading．Generally,ice-induced hearings develop in channel bar or point bar of course beds．Their genesis may be divisible into three types;the first is formed by dropping deposition of ice-melt water；the second is formed by vaulting resulting from the breakdown caused by ice melting；the third is formed by dropping deposition from a ice hole． The unusual hydrology,hydrodynamics and climate conditions in Yellow River make the ice beds containing(a great deal)mud-silt or the ice beds covered by mud-silt．As those ice beds melt,the mud-silt contained in the ice beds covering the ice beds will drop to the ground surface with ice melt water and form ice-induced heaving in the relevant position．If a hole develops in the ice bed and in the meantime,it is also covered by a layer of mudsilt,and when the ice bed melt,a heaving will be formed in the relevant position due to vaulting．If the ice bed formed in erosion pit in the point bar or channel bar has a hole or a crack,the mud-silt will drop into the pit with the ice melt water along the hole or crack to form a heaving． Ice-induced heavings are formed in an exposure and lower temperature(±0℃)conditions and their genesis is related to the complex interactions of ice and sand．