Yellow River's Contribution to the Building of Yangtze Delta During the Last 500 Years ‐ Evidence From Detrital Zircon U‐Pb Geochronology

Abstract

Mega delta, commonly placed in the continental margin, is a product of intimating interaction between the land and sea. Its formation processes are both affected by fluvial and marine dynamics. Modern deltas were built by aggradation and progradation through the deposition of sediment supplied from the rivers and marine sources over thousands of years during the Holocene. Deltas and the nearby coastal areas have offered habitat for over 500 million people on the planet, however, nowadays are under threaten of land loss due to changing climates (e.g., sea level rising) and strong human activities induced sediment flux decrease (Renaud et al., 2013;Syvitski et al., 2005Syvitski et al., , 2009. It becomes increasingly crucial for a clear understanding and assessment of the impacts of climate change and human activities on the delta system to better predict the fate of delta in the coming decades.The Yangtze Delta (YD), one of the world's largest deltas, is mainly supplied by the Yangtze River (YZR) sediments. It has experienced rapid growth during the last 2000 a, with a prograding rate reaching as high as 38-80 m/a (Hori et al., 2001) (Figure 1d). How such accelerated progradation happened has long been the subject of research. The classical view acknowledged that sediment flux increase resulted from intensified human activities in the YZR basins over the past 2000 a was mainly responsible for this (Chen et al., 1979;Wu et al., 1996). However, some studies have proposed a remote connection of the Yellow River (YR) to the building of YD through alongshore currents since 600-400 a (

Changjiang Delta in the Anthropocene: Multi-scale hydro-morphodynamics and management challenges

“…5b). The Yellow River sediment source to CD was confirmed by indicators including magnetic properties, clay minerals, rare earth elements, and isotope fingerprints, although the quantity remains understudied (Liu et al, 2010b;Wang et al, 2020;Shang et al, 2021). As the Yellow River shifted its river course far north after 1855, the abandoned Yellow River delta underwent erosion and the eroded sediment may still reach the CD and impose some influences.…”

“…The shelf currents play a role in modulating the river plume and seaward sediment dispersion (Liu et al, 2021). To the north of the CD, the Subei Currents are perennially southward, which can drive sediment transport from the abandoned Yellow River delta towards the CD, supplying sediment in building up the northern delta plains (Wang et al, 2020;Shang et al, 2021), even to the depocenter zone (Liu et al, 2010b). A recent monitoring and modeling study, however, suggests northward penetration of a branch of Changjiang plume in summer, to the shoreward of the Subei Currents (Wu et al, 2018a).…”

“…Part of the Yellow River-delivered sediment was transported southward by the Subei Currents, supplying an amount of 30-70 Mt. yr − 1 sediment in building up the northern CD plains (Zhou et al, 2014;Jia et al, 2018), particularly when the Yellow River discharged into the Yellow Sea at a place ~320 km to the north of CD (Shang et al, 2021;Fig. 5b).…”

The Changes in Drainage Systems of Weihe Basin and Sanmenxia Basin Since Late Pliocene Give New Insights Into the Evolution of the Yellow River

“…Detrital zircon U-Pb geochronology has long been regarded as a powerful tool to constrain the provenance of terrigenous sediments and the evolution of sedimentary basins (Dickinson et al, 1983;Gehrels et al, 2003;Zheng et al, 2020;Shang et al, 2021). Comparing zircon ages with sediments that accumulate from potential source areas could provide a comprehensive view of potential source areas (Gehrels, 2012).…”

Rewriting the Cambrian Biogeography of the Central Asian Orogenic Belt Using Combined Faunal Cluster, Zircon Age and C Isotope Analysis

“…All obtained U-Pb ages were plotted as histograms with 25 Ma bins using IsoplotR (Vermeesch, 2018). Den-sityPlotter® (Vermeesch, 2012) was used to calculate Kernel Density Estimates (KDE) for studied Mongolian terrains (Figure S3.2), DataGraph® to calculate cumulative probability plots (Figure S3.3) and a Matlab® package for a multi-dimensional scaling (MDS) plot (Shang et al, 2021;Vermeesch, 2013;Figure S3.4).…”