Grain size characteristics of surface sediment and its response to the dynamic sedimentary environment in Qiantang Estuary, China

2022 ◽  
Author(s):  
Shanshan Wang ◽  
Cunhong Pan ◽  
Dongfeng Xie ◽  
Mingwei Xu ◽  
Yuhan Yan ◽  
...  
Keyword(s):  
Grain Size ◽  
Surface Sediment ◽  
Sedimentary Environment

scholarly journals Geochemistry of Surface Sediments From the Emperor Seamount Chain, North Pacific

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Chen ◽  
Jianjun Zou ◽  
Aimei Zhu ◽  
Xuefa Shi ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Depth ◽  
Surface Sediment ◽  
North Pacific ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific ◽  
Emperor Seamount Chain

Investigating the composition and distribution of pelagic marine sediments is fundamental in the field of marine sedimentology. The spatial distributions of surface sediment are unclear due to limited investigation along the Emperor Seamount Chain of the North Pacific. In this study, a suite of sedimentological and geochemical proxies were analyzed, including the sediment grain size, organic carbon, CaCO3, major and rare earth elements of 50 surface sediment samples from the Emperor Seamount Chain, spanning from ∼33°N to ∼52°N. On the basis of sedimentary components, we divide them into three Zones (I, II, and III) spatially with distinct features. Sediments in Zone I (∼33°N–44°N) and Zone III (49.8°N–53°N) are dominated by clayey silt, and mainly consist of sand and silty sand in Zone II. The mean grain size of the sortable silt shows that the hydrodynamic condition in the study area is significantly stronger than that of the abyssal plain, especially at the water depth of 1,000–2,500 m. The CaCO3 contents in sediments above 4,000 m range from 20 to 84% but decrease sharply to less than 1.5% below 4,000 m, confirming that the water depth of 4,000 m is the carbonate compensation depth of the study area. Strong positive correlations between Al2O3 and Fe2O3, TiO2, MgO, and K2O (R > 0.9) in the bulk sediments indicate pronounced contributions of terrigenous materials from surrounding continent mass to the study area. Furthermore, the eolian dust makes contributions to the composition of bulk sediments as confirmed by rare earth elements. There is no significant correlation between grain size and major and minor elements, which indicates that the sedimentary grain size does not exert important effects on terrigenous components. There is significant negative δCe and positive δEu anomalies at all stations. The negative Ce anomaly mainly exists in carbonate-rich sediments, inheriting the signal of seawater. The positive Eu anomaly indicates widespread volcanism contributions to the study area from active volcanic islands arcs around the North Pacific. The relative contributions of terrestrial, volcanic, and biogenic materials vary with latitude and water depth in the study area.

scholarly journals Sediment Sources and Dispersion on the Western Sunda Shelf, Malay Peninsula, Southern South China Sea

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2823
Author(s):  
Yanguang Liu ◽  
Chuanshun Li ◽  
Ramlan Bin Omar ◽  
Xuefa Shi ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Surface Sediment ◽  
Surface Sediments ◽  
The Other ◽  
Coarse Grained ◽  
Malay Peninsula ◽  
Sediment Sources ◽  
Southern South China Sea ◽  
Sunda Shelf ◽  
Sediment Samples

Thirty-nine surface sediment samples collected from the western Sunda Shelf off the Malay Peninsula (WSSMP) in the southern South China Sea (SCS) were analysed for grain size, major and trace elemental compositions, and light/heavy mineral contents to trace the sediment sources and their transport mechanisms in the study area. In the WSSMP, the surface sediments are relatively poorly sorted but transportable. A principal component analysis of 37 elements and grain size fractions indicates that the surface sediments can be grouped into four major assemblages in the study area. Integrating with the light/heavy minerals data in the 63–125 μm fractions of the surface sediment samples, to better trace the sediment sources of the coarse-grained components in the marine environment, the study area can be further divided into four sediment provinces. Province I is located in the northwestern part of the study area. The concentrations of TiO2, Na2O, garnet, siderite, and glauconite in Province I were higher than in the other provinces. The main sediment source for this province originated from the Kelantan River and the Gulf of Thailand transported by the northeastern monsoon current. Province II is located offshore of the Pahang and Endau Rivers. The percentages of TiO2, rare earth elements, Al2O3, quartz, plagioclase, hypersthene, and magnetite in the surface sediments were typically higher in this province than in the other provinces. The Pahang and Endau rivers provide most of the sediments to this province, which are transported by southward coastal currents. Province III is located in the northeastern and eastern parts of the study area, where the coarse-grained sediment fraction had relatively high hornblende and biotite contents. Sediments in this province are mostly transported from the Mekong River during the northeastern monsoon. The other parts of the study area belong to Province IV, where the surface sediment elemental and mineral concentrations were mostly between those of the other three provinces. Therefore, we suggest that Province IV has a mixed source due to inputs from the surrounding rivers.

Environmental magnetism study of Lake Cadagno, Switzerland

2021 ◽  
Author(s):  
Artin Ali ◽  
Andrea Biedermann ◽  
Jasmine Berg ◽  
Mark Lever ◽  
Hendrik Vogel
Keyword(s):  
Grain Size ◽  
Sedimentary Environment ◽  
Environmental Magnetism ◽  
Late Glacial ◽  
Magnetic Minerals ◽  
Climate Conditions ◽  
Glacial Sediments ◽  
Depth Profiles ◽  
Magnetic Carriers ◽  
Lake Bottom

<p>Climate affects the mineralogy and grain size of sediments deposited in lakes. These properties are reflected in the sediment magnetic properties and can be characterized using magnetic methods. As part of the Cadagno-Project, which recovered several gravity and piston cores spanning the entire lake history from the deglacial to the present from the deepest part of permanently stratified Lake Cadagno, which is due to its peculiar water column chemistry considered an early Earth ocean analogue, our study aims to define changes in climate conditions during sedimentation. Here, we present a rock magnetic dataset (low-field magnetic susceptibility and its temperature dependence, anhysteretic and isothermal remanent magnetization (ARM, IRM), acquired in various fields, AF demagnetization, and hysteresis loops) that helps characterize the concentration, mineralogy, and grain size of magnetic carriers, and their variability with depth. Susceptibility, ARM, and IRM were measured on core sediments down to a depth of 886 cm below the lake bottom, providing a high-resolution record of the sedimentary environment of Lake Cadagno over the last 11,000 years. In addition to these depth profiles, detailed rock magnetic experiments were conducted at specific depths. The cores consist of pelagic sediments, flood turbidites, and late glacial sediments. In order to determine the characteristics of the background sedimentation, only turbidite-free intervals were included in this study. The depth profiles of susceptibility, ARM and IRM have approximately similar variations with depth. They show distinct peaks at the upper parts of the pelagic sediments (156-158 cm below the lake bottom,   ̴1280-1320 cal. Yr Bp) and of the late glacial sediments (826-844 cm below the lake bottom), which can be interpreted as increased concentration of ferromagnetic minerals or as a change in the magnetic mineralogy, in addition to decreasing trend in the background. Several intervals within the pelagic sediments are dominated by low-coercivity minerals (<10 mT), while higher coercivity grains (10–100 mT) contribute significantly at (150-170, 418-448 and 719-735 cm below the lake bottom). Magnetic grain size was analyzed using a Day plot, and shows that single domain magnetite dominates at (844 cm) below the lake bottom, indicating the presence of magnetotactic bacteria, which are believed to dwell mainly in the oxic–anoxic interface where chemical gradients are high. These results provide important constraints on the environmental conditions and climate change recorded by the magnetic minerals in Lake Cadagno.</p>

Sedimentary environment prediction of grain-size data based on machine learning approach

2020 ◽  
Vol 8 (3) ◽  
pp. SL71-SL78
Author(s):  
Qiao Su ◽  
Yanhui Zhu ◽  
Fang Hu ◽  
Xingyong Xu
Keyword(s):  
Machine Learning ◽  
Grain Size ◽  
Prediction Model ◽  
Sedimentary Environment ◽  
Machine Learning Algorithms ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Data Set ◽  
Sedimentary Environments ◽  
Size Data

Grain size is one of the most important records for sedimentary environment, and researchers have made remarkable progress in the interpretation of sedimentary environments by grain size analysis in the past few decades. However, these advances often depend on the personal experience of the scholars and combination with other methods used together. Here, we constructed a prediction model using the K-nearest neighbors algorithm, one of the machine learning methods, which can predict the sedimentary environments of one core through a known core. Compared to the results of other studies based on the comprehensive data set of grain size and four other indicators, this model achieved a high precision value only using the grain size data. We have also compared our prediction model with other mainstream machine learning algorithms, and the experimental results of six evaluation metrics shed light on that this prediction model can achieve the higher precision. The main errors of the model reflect the length of the conversation area of sedimentary environment, which is controlled by the sedimentary dynamics. This model can provide a quick comparison method of the cores in a similar environment; thus, it may point out the preliminary guidance for further study.

scholarly journals Early to Mid-Holocene Palaeoenvironment Change and Sedimentary Evolution in the Xianghu Area, Zhejiang

2020 ◽  
Vol 17 (19) ◽  
pp. 7099
Author(s):  
Longbin Sha ◽  
Xianfu Li ◽  
Jiabing Tang ◽  
Junwu Shu ◽  
Weiming Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Organic Carbon ◽  
Hydrodynamic Force ◽  
Sedimentary Environment ◽  
Climatic Changes ◽  
Lake Area ◽  
Δ13c Values ◽  
Sedimentary Evolution ◽  
Organic Carbon Isotope ◽  
History Of

A 2.5 m long sediment core (XH-2) obtained from Xianghu area, near the Kuahuqiao site, were analyzed for grain size, diatom index, and geochemistry of organic carbon. The results of the total organic carbon (TOC) and stable organic carbon isotope (δ13C) in sediment samples from core XH-2 in the Xianghu area in Zhejiang Province have revealed the evolution history of sedimentary environmental and climatic changes during the breeding–prosperity–decline period of the Kuahuqiao culture. During 9300–8200 cal a BP, TOC contents were relatively high and stable, whereas δ13C values tended to be negative. This condition indicated that the climate was humid, and the sedimentary environment in the Xianghu area was stable. During 8200–7500 cal a BP, TOC contents presented a fluctuating declining trend, and δ13C values were significantly high, implying that the climate was arid, and the Xianghu area was gradually reduced to land. Thus, conducive conditions were provided for the development of the Kuohuqiao culture (7700–7400 cal a BP). From 7500 cal a BP, TOC contents obviously declined, and δ13C values were partially low, suggesting strengthened hydrodynamic force and wet conditions in the Xianghu area. This condition was related to the rise in sea level at approximately 7400 cal a BP, and the Kuahuqiao site became obsolete due to the transgression event. The TOC contents in core XH-2 were remarkably influenced by grain size, whereas no significant correlation existed between the δ13C variability and grain size. Sedimentary environment changes in the Xianghu area from 9300 to 6600 cal a BP, which was reflected by the TOC and δ13C records in core XH-2, accorded with the diatom results in this core and those in the Baima Lake area.

Spatial heterogeneity of surface sediment grain size and aeolian activity in the gobi desert region of northwest China

CATENA ◽  
2020 ◽  
Vol 188 ◽  
pp. 104469 ◽  
Author(s):  
Yaping Shen ◽  
Chunlai Zhang ◽  
Rende Wang ◽  
Xuesong Wang ◽  
Songbo Cen ◽  
...  
Keyword(s):  
Grain Size ◽  
Spatial Heterogeneity ◽  
Surface Sediment ◽  
Northwest China ◽  
Gobi Desert ◽  
Sediment Grain Size ◽  
Desert Region ◽  
Aeolian Activity

Analysis on Grain-Size Characteristics and Sedimentary Environment of Conglomerate Reservoirs in Ying-4 Section of Xingcheng Gas Field of Songliao Basin

2013 ◽  
Vol 734-737 ◽  
pp. 286-289
Author(s):  
Yu Sun ◽  
Xiu Li Zhang ◽  
Jin Yan Zhang ◽  
Chen Chen
Keyword(s):  
Grain Size ◽  
Sedimentary Environment ◽  
Songliao Basin ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Gas Field ◽  
Environment Analysis ◽  
Two Dimension ◽  
Sedimentary Characteristics ◽  
Fan Deltas

Aimed at difficulty of conglomerate in Ying-4 Section of Xingcheng Gas Field, Songliao Basin, which it is impossible to be carried out, using routine granularity analysis methods, and the iconic grain-size analysis is carried out. According to iconic two-dimension grain-size analysis, and contacting to fundamental sedimentary characteristics of conglomerate, sedimentary environment analysis is carried out. It is thought that this area is Shallow gravel-bed braided fluvial fan deltas, to braided fluvial delta transition, which supported an important geological foundation for the next disposition of exploration in Xingcheng Gas Field.

scholarly journals A synthetic map of the northwest European Shelf sedimentary environment for applications in marine science

2017 ◽  
Author(s):  
Robert J. Wilson ◽  
Douglas C. Speirs ◽  
Alessandro Sabatino ◽  
Michael R. Heath
Keyword(s):  
Grain Size ◽  
North Sea ◽  
Sedimentary Environment ◽  
International Investment ◽  
Marine Policy ◽  
Continuous Variables ◽  
Seabed Sediment ◽  
The North ◽  
Wide Range ◽  
The North Sea

Abstract. Seabed sediment mapping is important for a wide range of marine policy, planning and scientific issues, and there has been considerable national and international investment around the world in the collation and synthesis of sediment data sets. However, in Europe at least, much of this effort has been directed towards seabed classification and mapping of discrete habitats. Scientific users often have to resort to reverse-engineering these classifications to recover continuous variables such as mud content and median grain size that are required for many ecological and biophysical studies. Here we present a new set of 0.125 by 0.125° resolution synthetic maps of continuous properties of the northwest European sedimentary environment, extending from the Bay of Biscay to the northern limits of the North Sea and the Faroe Islands. The maps are a blend of gridded survey data, and statistically modelled values based on distributions of bed shear stress due to tidal currents and waves, and bathymetric properties. Recent work has shown that statistical models can predict sediment composition in British waters and the North Sea with high accuracy, and here we extend this to the entire shelf and to the mapping of other key seabed parameters. The maps include percentage compositions of mud, sand and gravel; porosity and permeability; median grain size of the whole-sediment and of the sand and the gravel fractions; carbon and nitrogen content of sediments; percentage of seabed area covered by rock; mean and maximum depth-averaged tidal velocity and wave-orbital velocity at the seabed; and mean monthly natural disturbance rates. A number of applications for these maps exist, including species distribution modelling and the more accurate representation of seafloor biogeochemistry in ecosystem models. The data products are available from doi:10.15129/07bc686e-a354-40de-8c08-372ced7aad64.

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