Analysis of the distribution and development of marine sand resources in the northeast sea of Hainan island

Around northeast sea of Hainan island, marine sand resources are rich, which have been deposited since Holocene, mainly distributed in the east mouth of Qiongzhou strait, Nandujiang river mouth, Puqian bay et al.Near the eastmouth of Qiongzhou strait, there is a large scale of marine sand resources with good continuity just on the tidal ridge regions with the area of hundreds square kilometers and the average thickness of 20-30 m, the largest up to 67 m, which are shaped by the powerful reciprocating tidal current of east-west direction.The marine sand resources are deposited at 5-20 m below sea level and the resource potential can reach to billions of cubic meters.Sea sand fraction is mainly for the fine sand and medium sand, good separation, and the average silt content is 0.7%.Lithological change is not big, easy to selecting.Sea sand physical performance is quite good, so the sea sands can be a good option for engineering construction.With more than 90% SiO₂ content and other low content of impurities, the marine sand can be used for casting, cement, glass and siliceous raw material, because the sands have a higher purity and loose structure.Further, the heavy mineral composition can also make a comprehensive utilization.Through comprehensive evaluation, there are development prospects for class A and class B in the east mouth of Qiongzhou strait shoal area, with one third area of the research region, which is first option of marine sand development.The development prospect for class B is still good between the Nandujiang river mouth and the Baisha shoal, but the development environment risk is much bigger, where the marine sand development should be more cautious.Further geological investigation needs to be taken in other study regions because the development prospects are not quite good or unclear.