Paleosalinity Records to Sea Level Change of the Northern Margin of the South China Sea in Early Jurassic

Key words: 
• the continental margin of South China Sea

Abstract: A largescale transgression occured in early Jurassic in the eastern Guangdong Province, the continental margin of South China Sea. The sea level change is recorded by the variation of paleosalinity. The ratios of Sr/Ba and B/Ga reflecting the paleosalinity changes are coincident with the sea level changes, the former is a positive correlation and the latter is a negative correlation. In this area, the curves of m (m= MgO/ Al2O3 100)values and B/Ga are similar but different in ranges. According to variation of paleosalinity together with the filling succession, evolution of sedimentary environments and facies, two transgressions and one regression for sea level change are recognized in this area. The tectonic setting of the northern margin of the South China Sea in early Jurassic was active relatively. The recycled foreland orogenic belt or the foreland uplift became the source provenance, and the basin developed in this region including Haifeng area had some characteristics of the peripheral foreland basin. The sea level change of early Jurassic revealed by the records of paleosalinity variation may be affected by the paleotethys closure.