Long-term morphodynamic evolution in the Modaomen Estuary of the Pearl River Delta, South China

He, Yong; Liu, Xiaojian; Duan, Zihao; Cheng, Lu; Hou, Peng; Lu, Chen; Wu, Yao

doi:10.1016/j.geomorph.2021.108057

Cited by 6 publications

(5 citation statements)

References 43 publications

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“…The outlets are morphologically separated by Wugui Mountains into two parts, i.e., Humen, Jiaomen, Hongqimen, and Hengmen in the east and Modaomen, Jitimen, Hutiaomen, and Yamen in the west (Figure 1A). Among these outlets, the Modaomen estuary features the highest flood discharge and sand transport rates (He et al, 2022). The vast palaeo-Modaomen estuary contained a series of bi-directional jet systems which played an important role to the formation of sandbars and the major seaward channel of Xijiang River (Wu et al, 2007).…”

Section: Study Areamentioning

confidence: 99%

“…Despite the fact that a relatively clear understanding of Holocene landform development has been established based on numerous records mentioned above, studies on the sedimentation processes of the southern estuary are limited. The Modaomen estuary, for example, is the largest mouth of the Peal River (Huang et al, 1982;He et al, 2022), but relevant sedimentation research is scarce (Zong et al, 2009b;Lu et al, 2020). Earlier research suggested that sedimentary records from estuary sites could provide information about the palaeoenvironment evolution in response to natural and human impacts during the Holocene (Wu et al, 2017;Xiong et al, 2018b;Chen et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Holocene sedimentary of the Pearl River Delta in South China: OSL and radiocarbon dating of cores from Zhuhai

Lin

Yan

et al. 2022

Front. Mar. Sci.

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Deltaic sediments provide a window for investigating delta development processes and the effects of human activities. Despite the fact that numerous studies have been conducted in the Pearl River Delta (PRD), the chronological data are still very limited, which hinder the detailed interpretation of the sedimentary records. The current study aims to establish high-resolution chronology on two cores from Zhuhai using quartz optically stimulated luminescence (OSL) and radiocarbon (14C) dating and, further, to reconstruct the Holocene sedimentary history of the PRD. Core P1-1 has a depth of 79 m and core P3-2 a depth of 60 m. Thirteen quartz OSL samples from P1-1 produced ages between 10.4 and 0.16 ka. Eight OSL and eight 14C ages from P3-2 span from 10.7 to 0.3 ka. The OSL and 14C dates show a good agreement above the depth of 26 m (1.4–0.3 ka), but with discrepancies at depths of 26–54 m. 14C ages (10.7–8.1 ka) are generally older (up to c. 2 ka) than quartz OSL ages, and the discrepancy decreases with depth. The age model shows three phases of the sedimentation process: (1) rapid accumulation rates of 7.48 (P1-1) and 7.52 (P3-2) m/ka between c. 10.7 and 7.5 ka in response to high sea level, (2) followed by a significantly reduced rate of 2.24 m/ka (P1-1) and a depositional hiatus (P3-2) from 7.5 to 2.5 ka as a result of reduced sediment supply and strong scouring by tidal processes, and (3) high sedimentation rates of 8.86 (P1-1) and 9.07 (P3-2) m/ka since 2.5 ka associated with intensive human activities and weakening tidal hydrodynamics. This sedimentary pattern is also evident in many other Asian deltas.

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Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Holocene sedimentary of the Pearl River Delta in South China: OSL and radiocarbon dating of cores from Zhuhai

Lin

Yan

et al. 2022

Front. Mar. Sci.

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“…The mouth bar is the shallow shoal in the middle of the two branches, with a depth of ∼3 m. The mouth bar has recently decreased in size because of sand mining activities in the estuary. Additionally, the channel migrated westward after 2013, and the eastern branch gradually disappeared (He et al., 2022). In this study, we primarily focused on the mouth bar located on the main path of water and sediment transport (Figure 1b).…”

Section: Study Areamentioning

confidence: 99%

“…As a result of sediment sink, the mouth bar was formed in the ME, resulting in spatial changes in the dynamic structure (Jia et al., 2015). In response to sediment input and human activities, the mouth bar had evolved significantly in recent years (He et al., 2022). Therefore, the ME is an ideal site to explore the formation of the ETM and its mechanisms based on complex estuarine morphology.…”

Section: Introductionmentioning

confidence: 99%

Formation of Turbidity Maximum in the Modaomen Estuary of the Pearl River, China: The Roles of Mouth Bar

Li¹,

Yang²,

Mo³

et al. 2022

JGR Oceans

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An estuarine turbidity maximum (ETM) functions as a filter and plays a key role in transporting suspended sediment. The features of ETM and their formation mechanisms vary with different types of estuaries. Their responses to morphological factors require further study. In this study, the Modaomen Estuary of the Pearl River was selected to examine the formation mechanisms of the ETM and roles of the mouth bar. Hydrodynamics, suspended sediment concentration, and sediment size distribution were measured via cruise shipboard in the mouth bar zone during the dry season of 2020, which indicated that the ETM occurred in the central and western bars. Furthermore, numerical modeling of an idealized estuary based on Delft3D was performed to explore the effects of the existence of a mouth bar on the dynamic structures causing the ETM, including saltwater intrusion, residual longitudinal circulation, and bed sediment resuspension. The results indicated that the existence of a mouth bar contributed to the occurrence of double residual circulations and enhanced bed shear stress on the mouth bar, which favor the ETM formation. In general, two different dynamic regimes were responsible for the ETM formation, that is, sediment trapping by saltwater intrusion and sediment resuspension induced by tidal currents. The mouth bar played a key role in these two mechanisms, including altering the estuarine circulation and bed shear stress. The results contribute to a better elucidation of the ETM formation in estuaries and provide scientific guidelines for estuarine management and engineering.

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“…Heavy rainfall arising from tropical storms and ENSO activity enhances river discharge and causes a large amount of sediments to enter the lower reaches of the delta region (Liu et al, 2017;Deng et al, 2018;Chen et al, 2020;Yan et al, 2022). In contrast, urbanization prevents the production of terrigenous debris and channel reformation (Zhou et al, 2019;He et al, 2022). This delta is a typical zone in which to research the evolution of river discharge and sediment input under the interaction of natural processes and human activity.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic variations and human activities have influenced sediment fluxes in the pearl river delta since the late holocene

Yang

Shang

et al. 2023

Front. Earth Sci.

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Climate change and human activity can both exert a role in the river discharge and sediment load in river deltas when the sea level remains relatively stable. The Pearl River Delta constitutes the metropolitan region of the Guangdong–Hong Kong–Macau Greater Bay Area, and its evolution in the past and future impacts the sustainable development of this region. In this manuscript, a core situated in the northern South China Sea, adjacent to Qiao Island of Zhuhai city in the Pearl River Delta, was selected to investigate the hydrodynamic variation influenced by tropical processes and the sediment flux imposed by human activities. Using paleosecular variations (PSVs) in geomagnetic field correlations constrained by seven radiocarbon ages, an ∼2.5 kyr chronology was provided for core sediments ∼2.8 m in length. The magnetic fabric results suggest that deposition was influenced by the two types of hydrodynamic-weak energy modulated by El Niño–Southern Oscillation (ENSO) activity and higher energy regulated by high-frequency tropical storms. The cyclic variations in the degree of anisotropy of magnetic susceptibility (P) indicate two periodic changes at approximately 300 and 100 years, which were forced by ENSO activity, while the ratio of lineation with foliation (q value) implies a higher energy flow period of 1.3–1.9 kyr, arising from strong tropical storms. Moreover, the high saturation remanence (SIRM) introduces more sediment flux, which is impacted by growing human activity during the period of 1.0–1.6 kyr.

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Long-term morphodynamic evolution in the Modaomen Estuary of the Pearl River Delta, South China

Cited by 6 publications

References 43 publications

Holocene sedimentary of the Pearl River Delta in South China: OSL and radiocarbon dating of cores from Zhuhai

Holocene sedimentary of the Pearl River Delta in South China: OSL and radiocarbon dating of cores from Zhuhai

Formation of Turbidity Maximum in the Modaomen Estuary of the Pearl River, China: The Roles of Mouth Bar

Hydrodynamic variations and human activities have influenced sediment fluxes in the pearl river delta since the late holocene

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