The sedimentary characteristics and formation mechanism of shell ridges along the southwest coast of Bohai Bay

Abstract

The present paper studies the sedimentary characteristics and mechanism of the shell ridges on the southwestern coast of Bohai Bay, which are the largest and have the highest shell (or shell fragment) content in the world. These shell ridges are composed of two sedimentary subfacies: the ridge subfacies and the ridge infill subfacies with different inner textures and sedimentary structures. The ridge subfacies primarily consists of fresh shells and/or shell fragments with parallel beddings and high-angle oblique beddings. The ridge infill subfacies consists of finer shell fragments and silty sand with parallel beddings oblique to land. The evolution of the shell ridge is controlled by the accumulation of substantial shell material, the relative slow erosion of shoreline, storm waves, winds and the shift of river routes. Wind tunnel tests indicate that the critical movement velocity of shell is lower than that of quartz sand of the same grain size. Deltaic progradation alternates with shell ridge growth. While the Yellow River empties into the sea through this area, accompanied by deltaic progradating, the shell material is scarce, which is unfavorable to the growth of the shell ridge. Conversely, erosion occurs along an abandoned delta coast where a shell ridge may develop, e.g. the shell ridge on the southwest of Bohai Bay.

Notice of Retraction: Vegetation Distribution Characteristics and Shell Sand Physicochemical Properties in Shell Ridge on the Southwestern Coast of Bohai Bay

“…Shell ridges are the distinctive deposits lying on the upper surface of tidal flats where shellfish grow in abundance and fresh water is scarcely discharged [1]. The occurrence of them was reported in China, USA and Suriname in South America [1,2].…”

“…The occurrence of them was reported in China, USA and Suriname in South America [1,2]. Their formation is usually in groups or individual and often interrupted by rivers or tidal channels.…”

“…There are four shell ridges with the average thickness of 2~4 m in this area, and the greatest is about 258 km long. The formation mechanism and spatial distribution have been studied, and results indicate that the formation of shell ridge has gone through more than 2000 years [1,3]. The occurrence of shell ridge along the southwestern coast of Bohai Bay provides a habitat for plants and animals.…”

Threshold effects of photosynthetic efficiency parameters of wild jujube in response to soil moisture variation on shell beach ridges, Shandong, China

“…Shell ridges are distinctive shell sand deposits lying on the upper surface of tidal flats where fresh water discharge is minimal (Liu et al 2005). Scientists in Suriname and China had reported the occurrence of shell ridges (Meldahl 1995;Liu et al 2005).…”

“…Scientists in Suriname and China had reported the occurrence of shell ridges (Meldahl 1995;Liu et al 2005). Most existing research on shell ridges has focused on coastal geomorphology, sea level and climate changes, and coastal ecosystem evaluation (Saito et al 2000), photosynthetic and physiological characteristics of three shrubs species in field environments (Xia et al 2009), vegetation quantities characteristics, and the relationship between shell sand properties and vegetative distribution (Zhao et al 2011).…”