KẾT QUẢ BƯỚC ĐẦU NGHIÊN CỨU TỐC ĐỘ LẮNG ĐỌNG,  NGUỒN TRẦM TÍCH ĐÁY VỊNH HẠ LONG: DẤU HIỆU  TỪ KHOÁNG VẬT SÉT, ĐỒNG VỊ 210Pb VÀ 137Cs

Vuong, Bui Van; Liu, Zhifei; Thạnh, Trần Đức; Huh, Chih-An; Nhon, Dang Hoai; Ve, Nguyen Dac; Huy, Dinh Van

doi:10.15625/1859-3097/16/1/6527

Cited by 8 publications

(23 citation statements)

References 22 publications

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“…The sediment volume that had to be dredged to maintain a minimum depth of the navigation channels was about 0.78 × 10 6 m 3 in 2013 and 1.17 × 10 6 m 3 in 2015 with a high induced cost (e.g., 6.6 million USD in 2013) [31]. Many studies were recently devoted to find the cause of siltation in the navigation channel deposition and to propose solutions, focusing on geomorphology [32], geology [33], hydrodynamics and sediment transport [34][35][36][37][38]. Lefebvre et al [38] showed in particular that tidal pumping created a net upstream transport of sediments which settled in a near-bed layer at low turbulent energy, causing the silting up of the channels of Hai Phong port, particularly in the dry season.…”

Section: Introductionmentioning

confidence: 99%

Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Vinh¹,

Ouillon

2018

Water

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Abstract:This study aims at exploring the characteristic parameters of the Estuarine Turbidity Maxima (ETM) and at investigating their tidal variations within the Cam-Nam Trieu estuary (North Vietnam) during the early wet season. Six longitudinal river transects were performed at spring tide. Two types of ETM were observed: an upper well mixed ETM with high Suspended Particulate Matter (SPM) concentrations up to the surface at low salinity (0.11 to <1 psu), and a lower ETM confined in a bottom layer over stratified waters at salinities between~1 psu and 15 psu. Their length depended on the longitudinal salinity gradient and was highest at low tide than at high tide. D 50 of the flocs varied between 35 and 90 µm, their excess of density between 60 and 300 kg m −3 and their settling velocity ranged from 0.07 to 0.55 mm s −1 with values between 0.12 and 0.40 mm s −1 in the core of ETMs. The average fractal dimension of flocs was estimated to vary between 1.93 (at high tide) to 2.04 (at low tide).

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Section: Introductionmentioning

confidence: 99%

Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Vinh¹,

Ouillon

2018

Water

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“…This indicates a fact that open pits coal mining, that was practised in the past, contributed soil from the unstabilized tailings into the Bay (Figure 5). Peninsular coastal Malaysia 0.2-0.42 [44] Brunei Bay, Malaysia 0.47-2.13 [45] Gulf of Ton Kin 0.47-0.75 [21] Central Ha Long Bay 0.45 ± 0.17 much lower than the Redfield Ratio of 106:16:1 characterized for marine phytoplankton. Sediment with C:N:P lower than the Redfield Ratio has also been reported from other tropical river mouths [48,49].…”

Section: Discussion Temporal and Spatial Variation Of Sedimentation Rate In The Ha Long Baymentioning

confidence: 99%

“…Investigating the mineralogy of bottom sediment in Ha Long Bay, Bui Van Vuong, et al [21] have shown that the sediment accumulating in bottom of Ha Long Bay was derived not only from the local soil, but also from soil eroded inland and carried by the Red River and Thai Binh River systems. However, the temporal and spatial variations of sedimentation rate in the Bay were not systematically studied yet.…”

Section: Introductionmentioning

confidence: 99%

Sedimentation Rate Estimation and Tracing Organic Carbon and Nutrients Sources in Sediment of Ha Long Bay (Vietnam)

Dinh¹,

Quang²,

Van³

et al. 2021

Int J Earth Sci Geophys

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Sedimentation rate (SR) and sources of organic carbon, nitrogen and phosphorus nutrients in sediment of the Ha Long Bay (Vietnam) were estimated and assessed by the use of the 210 Pbex technique and based on isotopic signatures of carbon and nitrogen (δ 13 C and δ 15 N) in organic matter presents in sediment. It was revealed that SR in Ha Long bay varied temporally and spatially. In the early 1900, SR ranged from 0.25 to 0.40 cm a -1 , but it gradually increased up to 0.5-2.1 cm a -1 in recent years. SR in the Bay decreased from the coast seawards. The temporal variation of SR was attributed to anthropogenic causes whilst spatial variation of SR was attributed to the difference of sediment sources supplied to the Bay. Concentrations of nitrogen and phosphorus in sediment are correlated with each other (R 2 = 0.86) implying the nutrients were from the same source. The δ 13 C in total organic matter (TOM) ranges from -26.58‰ to -24.78‰ and δ 15 N ranges from 4.45 to 5.56‰. The results obtained suggested significant contribution of terrestrial carbon of C3 plants into the aquatic environment of the Bay. The contribution of terrigenous organic carbon into the Bay was estimated to be as high as from 65 to 92%.

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“…Nguồn từ hệ hống sông Hồng đã giảm đi khá nhiều khi đi vào Vịnh Hạ Long thông qua các kênh Cái Tráp, Lạch Huyện, Hoàng Châu và vòng qua đảo Cát Bà. Từ trước 1990 thành phần khoáng vật sét có nguồn gốc từ sông Hồng khá cao, kể từ sau 1990 thì nguồn cung cấp từ phong hóa bóc mòn các đá xung quanh đi vào Vịnh Hạ Long cao hơn [7]. Ở quần đảo Cát Bà và Vịnh Hạ Long sinh vật có tổng số 4622 loài cả ở trên cạn và dưới nước.…”

Section: Mở đầUunclassified

“…pH trầm tích chịu ảnh hưởng của cả môi trường biển và lục địa và giá trị pH nằm trong ngưỡng của môi trường tự nhiên (6,(5)(6)(7)(8)5), giá trị pH dao động từ 6,96 đến 8,09, trung bình 7,25 (Bảng 2).…”

Section: Ph Và Eh Trầm Tíchunclassified

Major Characteristics of Surface Sediments Within the Shallow Water of the Cat Ba Island, North Vietnam

Hoàng¹,

Vuong²,

Egidarev³

et al. 2020

EES

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The Cat Ba is one of the largest Islands offshore North Vietnam, which is characterized by an abundance of coral reefs in the East and Southeast of the island. The surface sediments are considered the basic elements for the coral ecosystem development. In this study, the authors present some new results studying pH, Eh, mineral composition, and grain size as the basic information for environmental assessment of this area. The results show that the pH value of the surface sediment varies from 6.90 to 8.09, with an average of 7.24 while the Eh value of the sediment ranges from -121.10 to -48.20mV, an average of -68.39mV, demonstrating a reducing environment. The surface sediments have been classified into 8 size classes: the coarse silt > very coarse silt > medium sand, very fine sand > very coarse sand, fine sand > coarse sand, very fine gravel. Most of the sediments are poorly sorted - very poorly sorted, only a few sedimentary samples are well sorted, moderately sorted, and moderately well sorted. The average mineral composition of the surface sediments consists of: 25% quartz, 17% illite, 16% aragonite, 13% kaolinite, 10% calcite, 5% chlorite, 4% gothite, 3% halite, 2% feldspar and less montmorillonite, and dolomite. These results allowed the researcher to interpret that the sediments have been deposited in a relatively calm environment and the terrigenous sediment sources are dominant over the marine sources. Source marine sediment groups are characterized by coarse grains, high pH, and are rich in carbonate minerals, which have been produced by biological materials. In contrast, the terrigenous sediment group is dominated by fine-grained sediments, rich clay minerals, quartz, and gothite. These fine-grained sediments are commonly distributed in the area and are favorable places for pollutant accumulation.

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KẾT QUẢ BƯỚC ĐẦU NGHIÊN CỨU TỐC ĐỘ LẮNG ĐỌNG, NGUỒN TRẦM TÍCH ĐÁY VỊNH HẠ LONG: DẤU HIỆU TỪ KHOÁNG VẬT SÉT, ĐỒNG VỊ 210Pb VÀ 137Cs

Cited by 8 publications

References 22 publications

Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Estuarine Turbidity Maxima and Variations of Aggregate Parameters in the Cam-Nam Trieu Estuary, North Vietnam, in Early Wet Season

Sedimentation Rate Estimation and Tracing Organic Carbon and Nutrients Sources in Sediment of Ha Long Bay (Vietnam)

Major Characteristics of Surface Sediments Within the Shallow Water of the Cat Ba Island, North Vietnam

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