关键词: 埋藏古河道, 全新世, 沉积特征, 海平面变化, 漠阳江

Abstract: As one of migration channels between sediment source and sink, the influence of paleochannel on sedimentary budgets has attracted much attention from marine sedimentologists. In order to study the sedimentary characteristics of buried paleochannel in the Shapa area of Yangxi, Guangdong, paleochannels on coastal shelves have been characterized in western Guangdong. Based on the survey data of shallow strata profile of offshore wind farms and boreholes, several buried paleochannels have been firstly identified by the acoustic pulse characteristics. The results show that the channel cross sections are mainly in the shape of wide “U”, with width of 768-2 743 m and a maximum incision depth of 16.90 m, and there is a local confluence of paleochannels. Based on the modern river type discrimination method, the regional paleochannel belongs to the gravel branch type, mainly transporting sand and gravel, with an average annual transport volume of 3.87×108 m3/a. Regional paleochannels were formed in the early to middle Holocene originating from the ancient Moyang River system, and covered by the shallow marine deposits since the middle Holocene. This finding makes up the gap in the distribution of paleochannels in the shallow coastal area of western Guangdong.

Key words: buried paleochannels, Holocene, sedimentary characteristics, sea level change, Moyang River