Study On The Chatacteristics Of Surface Sediment In The Qiantang River And Analysis Of Provenance

In this paper, centering the characteristics of the river sediments of the Qiantang River, the environment and the material source have been deeply discussed. Through sampling at the mainstream (Xin’an River, Fuchun River, Qiantang River and Hangzhou Bay), tributaries (Lan River, Fenshui River, Huyuan River, Luzhu River, Puyang River and Cao’e River) and the nearby river (Yong River and the Yangtze River estuary), analyzed the characteristics and differences of sediments in different sections of the main stream and main tributaries by granularity, environmental magnetism and environmental geochemistry. On this basis, analyzed hydrodynamic environment, source of material and the facters of sediment characteristics. Concludes as follows:(1) The surface sediments mainly is clayey silt (YT), silty sand (T). There are still a small amount of sand, clayey silt (S-YT), clay, silty sand (Y-ST), sandy silt (ST), silty sand (TS), silt-clay sand (T-YS). Mean Size (Mz) is between 4.07～7.73φ, average is 6.20 (p, the particle is fine; Sorting coefficient varys from 1.21 to 3.24 and sorting is poor and poor; Partial state coefficient is from -0.14 to 0.58, the symmetric at Fuchun River and tributaries. Very positive skewness locates in the Qiantang River. Hangzhou Bay multi is partial; Kurtosis are between 0.63～2.67, which is wide peaks in Fuchun River and its tributaries. Kurtosis of Qiantang River Sediment are very narrow peaks, and that of Hangzhou Bay are mainly secondary peaks and narrow peak. Probability cumulative curves reflect that hydrodynamic is strong of the Qiantang River, Yong River, the Yangtze River estuary, Cao’e River estuary. River runoff rises and falls fastly of Fuchun River and its tributaries, Puyang River and upper Cao’e River. Hydrodynamic is relatively weak at the Hangzhou Bay. Pejrup triangular diagram reflects the the same hydrodynamic characteristics.(2) The river sediments and topsoil of the Huyuan River, Cao’e River Basin contain high magnetic mineral, which due to the parent material. Ferrimagnetic mineral content is relatively small in the Qiantang River, Hangzhou Bay Sediments, which is similar to the Yangtze River estuary. Magnetic minerals are relatively abundant in the Fuchun River. Ferrimagnetic minerals dominated the magnetic characteristics by relativity of x with SIRM, demagnetization parameters. In addition, incomplete antiferromagnetic minerals have great contribution in the Xin’an River, Luzhu River and the topsoil of upstream. Magnetic particles of Qiantang River sediments are mainly SSD and poor of SP. Magnetic particles of sediments of Huyuan River, Luzhu River, Cao’e River, and Fuchun River also contain MD-PSD. The soil of Qiantang River’ magnetic minerals is SSD with a lot SP. The correlation coefficient between magnetic parameters and grain size shows that magnetic minerals are mainly concentrated in the<16μm grain size.(3) In the Qiantang River, Ca, Mg, Na, Sr, Cr, Ni relative to UCC loss. Si, Al, K, Cu, Zn, Pb, Zr enrichment. Fe, Mn, Ti, P and UCC content is quite. Sediments of the Qiantang River inherits the characteristics of source rocks and sediments at source area, and are dominated by terrigenous sediments. The mean of CIA studied is 79.85, which shows medium to strong chemical weathering. The weathering degree of the upper river sediments is higher than that of estuary. Hydrodynamic sorting and the source material from Yangtze River impact chemical composition of sediments of estuary. And chemical weathering and material source affect chemistry composition of sediments of Fuchun River and its tributaries.(4) Established the source-sink relationship of the Qiantang River and tributaries by "Pro source" of grain size, environmental magnetism, and geochemistry. Sediments of Fuchun River are mainly coming from Lan River and Fenshui River. Xin’an River, Luzhu River, Huyuan River contribute litter; Sediments of the Qiantang River, Hangzhou Bay are mainly from the Yangtze River. Fuchun River, Puyang River and Cao’e River import litter.(5) Studing of the 26 variables of grain size, environmental magnetism, element geochemistry of Qiantang River sediments by principal component analysis,which shows that the common controlling factors of sediment characteristics are dynamic environment, the chemical weathering and provenance. The magnetic mineral content is the controlling factor of the magnetic parameter, the type of the magnetic mineral and the grain character also have a great influence.