Strata sequence and paleochannel response to tectonic, sea-level, and Asian monsoon variability since the late Pleistocene in the South Yellow Sea

2019 ◽  
Vol 92 (2) ◽  
pp. 450-468 ◽  
Author(s):  
Liyan Wang ◽  
Guangxue Li ◽  
Jishang Xu ◽  
Yong Liu ◽  
Lulu Qiao ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Yellow Sea ◽  
Yellow River ◽  
Seismic Profile ◽  
Sediment Supply ◽  
The Yellow Sea ◽  
South Yellow Sea ◽  
Sea Level Changes ◽  
Quaternary Period

AbstractThe continental shelf strata provide information regarding sea-level fluctuation and climate changes in the Quaternary period. A 5831.47-km-long high-resolution seismic profile and borehole core (YS01) were acquired to reconstruct the evolutionary history of the strata in South Yellow Sea (SYS) during the late Pleistocene. The strata recorded three transgression events (HI, HII, and HIII) and three stages of paleochannel development (LI, LII, and LIII). Based on the distribution, thickness, and volume of the strata formed in the three transgressions, we concluded that the scale of the three transgressions during the late Pleistocene was HIII, HI, and HII, in descending order. In addition, our data show that the Yellow River extended to the Yellow Sea Trough during the last glacial maximum. The influence of the tectonic framework on sedimentation in the SYS was completely concealed by sea-level changes and sediment supply in the late Pleistocene (~Marine Isotope Stage 5). Since then, the accommodation space, a crucial prerequisite for sedimentation, has been controlled solely by sea-level changes in the SYS. Furthermore, two “source to sink” models of the neritic shelf in the marine and terrestrial environments were established, including high sea-level and shelf-exposure models.

The Mudflat System of China

1983 ◽  
Vol 40 (S1) ◽  
pp. s160-s171 ◽  
Author(s):  
Ying Wang
Keyword(s):  
Yellow Sea ◽  
Yellow River ◽  
Sediment Supply ◽  
The Yellow Sea ◽  
The Yellow River ◽  
Intertidal Mudflat ◽  
Bohai Bay ◽  
Intertidal Flat ◽  
Coastal System ◽  
Sparse Vegetation

Most of the 2000 km of intertidal mudflat on the Chinese coastline is developed in the mesotidal Bohai Sea, where the Yellow River now discharges, and on its pre-1855 delta 600 km to the south on the Yellow Sea coast. The Yellow River has the largest sediment suspended load of any river in the world, with an average of 24.7 kg of sediment per cubic metre of water at its mouth. Four hundred million tons of sediment are deposited annually in the lower reaches of the river, and 1200 million tons are transported to sea in the surface mud plume. This accumulates either in the deeper waters of Bohai Bay or on the intertidal mudflats. These mudflats are typically 3 km wide, but are up to 18 km wide at the delta. They are divided into four zones: the polygonal zone with mud cracks and sparse vegetation above normal HTL; the inner depositional zone of mud on the higher part of the flat; a central erosional zone; and an outer depositional zone of silt on the lower intertidal flat. Landwards a salt marsh is developed. Seawards the sediment passes from sandy silt at LTL to fine mud (silt and clay) in water depths of 10 m. The historical changes in the course of the Yellow River are well known, and the formation of cheniers on the Bohai Bay coast can be correlated with times when there was little or no fluvial sediment supply. For almost 700 yr prior to 1855, the Yellow River discharged to the Yellow Sea in North Jiangsu. Submarine sand bars reworked by tidal currents from the submerging former delta mouth protect about 200 km of coastline from erosion, and intertidal flats are prograding. Elsewhere in North Jiangsu, coastal retreat is rapid, and in places a modern chenier-like shell beach is developing. The history of development of this entire coastal system is dominated by the Yellow River and anthropogenic modifications of its basin.Key words: sediment, mudflats, Yellow River, Bohai Bay, China

Identification of Yangtze River and Yellow River Paleochannels in South Yellow Sea Shelf

2013 ◽  
Vol 664 ◽  
pp. 27-31
Author(s):  
Zhao Jun Song ◽  
Jin Zhou ◽  
Qiao Chen ◽  
Zhen Kui Gu
Keyword(s):  
Continental Shelf ◽  
Yellow Sea ◽  
Yangtze River ◽  
Yellow River ◽  
River Sediments ◽  
The Yangtze River ◽  
South Yellow Sea ◽  
The South ◽  
Research Results ◽  
The South Yellow Sea

research of submarine paleochannels has not only a great significance in exploring the evolution of palaeoenvironment of continental shelf but also a practical application value in solving problems on disaster geology and environmental geology in the continental shelf development. Yellow River and Yangtze River both were concentrated in the northern Jiangsu to enter the South Yellow Sea Basin in the Last Glacial, playing an important role in the palaeoenvironment evolution of the South Yellow Sea. On the basis of integrating previous research results and researching a large number of shallow stratigraphic sections of paleochannels in the South Yellow Sea Shelf in detail, identification and research of Yangtze River and Yellow River paleochannels in the South Yellow Sea Shelf are carried out in this paper. Research results show that: the Yangtze River and Yellow River paleochannels in the South Yellow Sea continental shelf are significantly different in the river section, river pattern, major elements, as well as trace elements, clay minerals, carbonate content and heavy mineral assemblages in the river sediments and other aspects. These differences can be used as the evidence for identification of the Yangtze River and Yellow River paleochannels.

scholarly journals Dynamics of a Tidal Current System in a Marginal Sea: A Case Study of the Yellow Sea, China

2020 ◽  
Vol 7 ◽  
Author(s):  
Qian Zhang ◽  
Min Su ◽  
Peng Yao ◽  
Yongping Chen ◽  
Marcel J. F. Stive ◽  
...  
Keyword(s):  
Yellow Sea ◽  
Tidal Current ◽  
Current System ◽  
Tidal Wave ◽  
The Yellow Sea ◽  
Open Boundary ◽  
Sand Ridge ◽  
South Yellow Sea ◽  
The South ◽  
The South Yellow Sea

Tidal currents belong to the main driving forces shaping the bathymetry of marginal seas. A globally unique radial sand ridge field exists in the South Yellow Sea off the central Jiangsu coast, China. Its formation is related to the distinctive “radial tidal current” pattern at that location. A generally accepted hypothesis is that the “radial tidal current” is a consequence of the interference between the northern amphidromic tidal wave system and the southern incoming tidal wave. In this study, a schematized numerical tidal model was designed to investigate the tidal current system and the factors of influence in the South Yellow Sea. Concepts of the tidal current amphidromic point (CAP) and the tidal current inclination angle are utilized to analyze the inherent structure of the tidal current system. By conducting a series of numerical experiments, it is found that the Poincaré modes are necessary for the existence of “radial tidal current,” and the e-folding decay length should be smaller than the basin length. In the Yellow Sea, cross-basin phase differences due to lateral depth differences as well as open boundary conditions favor the emergence of the “radial tidal current.” Further analyses indicate that the CAP system (i.e., the co-inclination lines, the CAPs, and the tidal ellipticity) deepens the understanding on the dynamic structure of a tidal current system, and therefore, it deserves more attention in future studies.

The arrival of the paleo–Orinoco Delta at Trinidad: The Cruse Formation delta lobes and delivery to deepwater Atlantic

2020 ◽  
Vol 90 (8) ◽  
pp. 938-968
Author(s):  
Ariana Osman ◽  
Ronald J. Steel ◽  
Ryan Ramsook ◽  
Cornel Olariu ◽  
Si Chen
Keyword(s):  
Sea Level ◽  
Late Miocene ◽  
Sediment Supply ◽  
Average Height ◽  
Shelf Edge ◽  
Sea Level Changes ◽  
Orinoco Delta ◽  
Basin Floor ◽  
Shelf Margin ◽  
High Sediment

ABSTRACT Icehouse continental-shelf-margin accretion is typically driven by high-sediment-supply deltas and repeated glacio-eustatic, climate-driven sea-level changes on a ca. 100 ky time scale. The paleo–Orinoco margin is no exception to this, as the paleo–Orinoco River Delta with its high sediment load prograded across Venezuela, then into the Southern and Columbus basins of Trinidad since the late Miocene, depositing a continental-margin sedimentary prism that is > 12 km thick, 200 km wide, and 500 km along dip. The Cruse Formation (> 800 m thick; 3 My duration) records the first arrival of the paleo–Orinoco Delta into the Trinidad area. It then accreted eastwards, outwards onto the Atlantic margin, by shallow to deepwater clinoform increments since the late Miocene and is capped by a major, thick flooding interval (the Lower Forest Clay). Previous research has provided an understanding of the paleo–Orinoco Delta depositional system at seismic and outcrop scales, but a clinoform framework detailing proximal to distal reaches through the main fairway of the Southern Basin has never been built. We integrate data from 58 wells and outcrop observations to present a 3-D illustration of 15 mapped Cruse clinoforms, in order to understand the changing character of the first Orinoco clastic wedge on Trinidad. The clinoforms have an undecompacted average height of 550 m, estimated continental slope of 2.5° tapering to 1°, and a distance from shelf edge to near-base of slope of > 10 km. The clinoform framework shows trajectory changes from strong shelf-margin progradation (C10–C13) to aggradation (C14–C20) and to renewed progradation (C21–24). Cruse margin progradational phases illustrate oblique clinothem geometries that lack well-developed topsets but contain up to 70 m (200 ft) thick, deepwater slope channels. This suggests a high supply of sediment during periods of repeated icehouse rise and fall of eustatic sea level, with fall outpacing subsidence rates at times, and delivery of sand to the deepwater region of the embryonic Columbus channel region. Also, evidence of wholesale shelf-edge collapse and canyon features seen in outcrop strongly suggest that deepwater conduits for sediment dispersal and bypass surfaces for Cruse basin-floor fans do exist. The change to a topset aggradational pattern with a rising shelf trajectory may be linked to increased subsidence associated with eastward migration of the Caribbean plate. The Cruse-margin topsets were dominated by mixed fluvial–wave delta lobes that were effective in delivery of sands to the basin floor. The preservation of a fluvial regime of the delta may have been impacted by basin geometry which partly sheltered the area from the open Atlantic wave energy at the shelf edge. Ultimately, understanding shelf-edge migration style as well as process-regime changes during cross-shelf transits of the delta will help to predict the location of bypassed sands and their delivery to deepwater areas.

Nutrient sources in the Bohai Sea and Yellow Sea: results from seasonal sampling in 2018

2020 ◽  
Author(s):  
Shichao Tian ◽  
Birgit Gaye ◽  
Jianhui Tang ◽  
Yongming Luo ◽  
Tina Sanders ◽  
...  
Keyword(s):  
Yellow Sea ◽  
Bohai Sea ◽  
Yellow River ◽  
The Yellow Sea ◽  
Reactive Nitrogen ◽  
Nutrient Concentrations ◽  
The Yellow River ◽  
Isotopic Ratios ◽  
Nutrient Sources ◽  
The Bohai Sea

<p>The Bohai Sea and Yellow Sea are semi-enclosed basins strongly affected by human activities due to climate change and growing industries in China. Changes of hydrology, nutrient concentrations and sources and resulting ecosystem responses are therefore progressively intensifying during the last decades. In order to characterize nutrient sources and dynamics and to estimate the anthropogenic impact, we investigated nutrient concentrations and dual isotopes of nitrate in spring and summer 2018 in Bohai Sea and Yellow Sea. Furthermore, we sampled suspended matter and surface sediments and determined organic carbon, nitrogen and stable nitrogen isotopic ratios.</p><p>In spring, the water column was well mixed and the study area was mainly affected by the Yellow River diluted water and the Yellow Sea Warm Current water, which were the main nitrate sources. In summer, the water was stratified, and the Yellow River and Changjiang River diluted water supplied nutrients to an even larger region than in spring. During this season, the Yellow Sea Cold Water mass formed the bottom water of the Yellow Sea where nutrients became enriched. In contrast to other polluted marginal seas, the stable isotopic ratios of dissolved and particulate nitrogen are relatively low in the study area, which could be due to nutrient supply from the atmosphere or the open ocean. Using nitrogen isotopes, we developed a box model of reactive nitrogen for the Bohai Sea and quantified the input of atmospheric and riverine reactive nitrogen, submarine groundwater and water exchange with the Yellow Sea, constraining the budgets of reactive nitrogen combining mass fluxes with an isotopic balance. Including the isotopic balance improved the mass balance based only on nutrient concentrations.</p>

Late Pleistocene and Holocene Sea Level Changes in the Hisarönü Gulf, Southeast Aegean Sea

2012 ◽  
Vol 27 (3) ◽  
pp. 220-236 ◽  
Author(s):  
Nilhan Kızıldağ ◽  
A. Harun Özdas ◽  
Atilla Uluğ
Keyword(s):  
Sea Level ◽  
Late Pleistocene ◽  
Aegean Sea ◽  
Sea Level Changes ◽  
Holocene Sea Level
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