Provenance of Holocene sediments in the outer part of the Paleo-Qiantang River estuary, China

2015 ◽  
Vol 366 ◽  
pp. 1-15 ◽  
Author(s):  
Xia Zhang ◽  
Robert W. Dalrymple ◽  
Shou-Ye Yang ◽  
Chun-Ming Lin ◽  
Ping Wang
Keyword(s):  
Outer Part ◽  
River Estuary ◽  
Qiantang River ◽  
Holocene Sediments

scholarly journals Influence of inter-annual variability of river runoff on the bottom sediments of the Razdolnaya River estuary, Primorye, Russia

2020 ◽  
Author(s):  
В.М. ШУЛЬКИН
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
Bottom Sediments ◽  
River Runoff ◽  
Total Concentration ◽  
Outer Part ◽  
River Estuary ◽  
Size Composition ◽  
Amur Bay ◽  
The North

Изучены вариации гранулометрического и химического состава верхнего двухсантиметрового слоя донных отложений эстуария р. Раздольная, отобранных трижды в течение 2015–2019 гг., когда водный и твердый стоки реки выросли в 2–3 и 5–6 раз соответственно по сравнению с 2014 г. Показано, что значительный вынос осадочного материала сопровождается увеличением на 10–20 % доли пелитовых (<0,01мм) фракций в отложениях внешней части эстуария в северной части Амурского залива. Вариации гранулометрического состава являются главным контролирующим фактором и определяют 67 % общей изменчивости химического состава осадков эстуария. Еще 20 % изменчивости обусловлены примесью загрязненных отложений залива, содержащих повышенную концентрацию Сорг., Hg, Zn, Pb, Cd, Ag, Cu, Mo, V, а также восстановительным диагенезом, приводящим к обеднению осадков марганцем и кобальтом на разрезе река–море. Установить влияние коагуляционных процессов в зоне смешения на валовый состав донных отложений эстуария р. Раздольная не удалось. Grain size and chemical composition have been studied of the upper 2 cm layer of bottom sediments of the Razdolnaya River estuary sampled thrice in 2015–2019. It was a period when the river runoff increased by 2–3 and 5–6 times for the water and suspended solids, respectively, compared to 2014. It has been shown that significant subtraction of sedimentary material is accompanied by 10–20 % increase of pellite fractions (grain size <0.01 mm) in the deposits of the outer part of anestuary in the North part of the Amur Bay. Grain size composition is the main controlling factor determining 67 % of the total variability of the chemical composition of estuarine bottom sediments. Another 20 % of variability are due to the admix of polluted sediments of the Amur Bay, containing an increased concentration of Corg., Hg, Zn, Pb, Cd, Ag, Cu, Mo, V, as well as diagenesis, leading to depletion of sediments by the Mn and Co on a river-sea section. It is not possible to establish the influence of coagulation processes in the mixing zone on total concentration of trace elements in the bottom sediments of Razdolnaya River estuary.

Spatial structure, temporal variability, and dynamical features of small river plumes observed by aerial drones

2020 ◽  
Author(s):  
Alexander Osadchiev ◽  
Alexandra Barymova
Keyword(s):  
Spatial Structure ◽  
Internal Waves ◽  
Temporal Variability ◽  
Outer Part ◽  
River Estuary ◽  
River Plume ◽  
Small River ◽  
River Plumes ◽  
Dynamical Features

&lt;p&gt;We use optical imagery and video of ocean surface acquired from aerial drones (quadcopters) to study small river plumes formed in the northeastern part of the Black Sea. Quadcopters can continuously observe small river plumes with high spatial resolution from relatively low altitude. It provides unprecedented ability to study spatial structure of small river plumes, detect and measure their temporal variability, register various dynamical features of these plumes. In this work we describe and analyze strongly inhomogeneous structure of small river plumes manifested by complex and dynamically active internal frontal zones; undulate form of sharp front between small river plume and ambient sea and energetic lateral mixing across this front caused by frontal baroclinic instability; internal waves generated by river discharge near a river estuary and propagating within inner part of a plume; internal waves generated by vortex circulation of a river plume and propagating within outer part of a plume. The issues reported in this study remained mainly unaddressed before due to low spatial and/or temporal resolution of in situ measurements and satellite imagery used in previous related studies. We show that usage of aerial drones, first, strongly enhance in situ and satellite observations of structure and variability of small plumes, second, provides ability to perform accurate, continuous, and high-resolution measurements of their spatial characteristics and current velocity fields and, finally, significantly improves organization of operational field measurements. As a result, aerial drones are effective tools to obtain new qualitative insights and quantitative assessments of structure, variability, and dynamics of small river plumes.&lt;/p&gt;

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