Abstract
The sediment sources of the Yangtze Shoal were traced by analysing surface and core sediment particle size, detrital and clay minerals, carbon and nitrogen isotopes, and radioisotope dating. In the estuary, the sediments are dominated by silty clay, high stable mineral, and extremely high illite/chlorite. Stable organic carbon isotopes (δ13C-TOC) indicated a marine-dominated mixture. On the shoal, the sediments are mainly composed of fine sand, high unstable mineral. The δ13C-TOC indicated predominantly marine sedimentation. The average TOC of core sediments was ~0.26%, and the average TN was ~0.05%. The TOC/TN was 5.4–7.8, the δ13C-TOC was −19.8 to −22.1‰, and the age of the sediments spanned the last ~10.8 ka (Holocene). The sediments and provenance of the Yangtze Shoal have been controlled by the East Asian monsoon, sea level change, riverine sediment flux and ocean circulation. The intervals 8.3–6.3 ka and 3.8–1.5 ka, are characterized by Yangtze River sources, whereas 6.3–3.8 ka and 1.5–0.8 ka, are characterized by a source mixture with Yellow River input. Tracing the multiple sources effectively confirms the hypothesis that the southern Yangtze Shoal was a delta formed by combined sedimentation from the Yangtze River and Yellow River during times of low sea level.
Highlights
The Yangtze Shoal, the largest in the Yangtze Estuary with an area of 3 × 104 km[2], is located on the estuary’s eastern side[1,2]
In addition to the effects of tidal currents from the western North Pacific, the study area is affected by the Yellow Sea warm current, northern coastal stream, Taiwan warm current, Kuroshio Current and the Yangtze River diluted flow[7]
The Yellow Sea warm current and currents along northern Jiangsu carry with sediments, which are deposited in the northern and middle part of the study area under the action of rotational flow
Summary
The Yangtze Shoal, the largest in the Yangtze Estuary with an area of 3 × 104 km[2], is located on the estuary’s eastern side[1,2] It is a huge sandy sedimentary body that opens to the northwestern Pacific Ocean[3]. In this study (Fig. 2), sediment distribution patterns, their sources and types were determined by analysing particle size, detrital and clay minerals, and carbon and nitrogen isotope composition, as well as constructing a chronology with radio isotopic dating.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
