Based on one-year wave field data measured at the south part of the radial sand ridges of the Southern Yellow Sea, the wave statistical characteristics, wave spectrum and wave group properties are analyzed. The result...Based on one-year wave field data measured at the south part of the radial sand ridges of the Southern Yellow Sea, the wave statistical characteristics, wave spectrum and wave group properties are analyzed. The results show that the significant wave height （H1/3） varies from 0.15 to 2.22 m with the average of 0.59 m and the mean wave period （Tmean） varies from 2.06 to 6.82 s with the average of 3.71 s. The percentage of single peak in the wave spectra is 88.6 during the measurement period, in which 36.3% of the waves are pure wind waves and the rest are young swells. The percentage with the significant wave height larger than 1 m is 12.4. The dominant wave directions in the study area are WNW, W, ESE, E and NW. The relationships among the characteristic wave heights, the characteristic wave periods, and the wave spectral parameters are identified. It is found that the tentative spectral model is suitable for the quantitative description of the wave spectrum in the study area, while the run lengths of the wave group estimated from the measured data are generally larger than those in other sea areas.展开更多
According to a deformed mild-slope equation derived by Guang-wen Hong and an enhanced numerical method, a wave refraction-diffraction nonlinear mathematical model that takes tidal level change and the high-order bathy...According to a deformed mild-slope equation derived by Guang-wen Hong and an enhanced numerical method, a wave refraction-diffraction nonlinear mathematical model that takes tidal level change and the high-order bathymetry factor into account has been developed. The deformed mild-slope equation is used to eliminate the restriction of wave length on calculation steps. Using the hard disk to record data during the calculation process, the enhanced numerical method can save computer memory space to a certain extent, so that a large-scale sea area can be calculated with high-resolution grids. This model was applied to wave field integral calculation over a radial sand ridge field in the South Yellow Sea. The results demonstrate some features of the wave field： （1） the wave-height contour lines are arc-shaped near the shore; （2） waves break many times when they propagate toward the shore; （3） wave field characteristics on the northern and southern sides of Huangshayang are different; and （4） the characteristics of wave distribution match the terrain features. The application of this model in the region of the radial sand ridge field suggests that it is a feasible way to analyze wave refraction-diffraction effects under natural sea conditions.展开更多
The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncer...The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments.展开更多
The results of simulated tidal current field, wave field and storm-induced current field are employed to interpret the depositional dynamic mechanism of formation and evolution of the radial sand ridges on the Yellow ...The results of simulated tidal current field, wave field and storm-induced current field are employed to interpret the depositional dynamic mechanism of formation and evolution of the radial sand ridges on the Yellow Sea seafloor. The anticlockwise rotary tidal wave to the south of Shandong Peninsula meets the following progressive tidal wave from the South Yellow Sea, forming a radial current field outside Jianggang. This current field provides a necessary dynamic condition for the formation and existence of the radial sand ridges on the Yellow Sea seafloor. The results of simulated 'old current field (holocene)' show that there existed a convergent-divergent tidal zone just outside the palaeo-Yangtze River estuary where a palaeo-underwater accumulation was developed. The calculated results from wave models indicate that the wave impact on the topography, under the condition of high water level and strong winds, is significant. The storm current induced by typhoons landing in the Yangtze River estuary and turning away to the sea can have an obvious influence, too, on the sand ridges. The depositional dynamic mechanism of formation andevolution of the radial sand ridges on the Yellow Sea seafloor is ' tidal current-induced formation-storm-inducedchange-tidal current-induced recovery' .展开更多
A sand ridge field of 22 470 km2 consists of fine sands and silts originally from the old Changjiang River sediment during the late Pleistocene period. Late Holocene sand stratum with its well-preserved larmnary beddi...A sand ridge field of 22 470 km2 consists of fine sands and silts originally from the old Changjiang River sediment during the late Pleistocene period. Late Holocene sand stratum with its well-preserved larmnary bedding of more clay particles reflects the influence from the Yellow River. There are three genetic types of morphology of sand ridge field as follows: (i) reformed alluvial sandy bodies and old river valleys, located in the central and southern parts, formed from the end of Pleistocene to the present. (ii) Radiative current ridges and patrimonal valley type, located in the northeastern part, formed during the early or middle Holocene time. (iii) Eroded-depositional sandy bodies in the north and outer parts, and erosional trough in the north formed since the middle Holocene transgression.The sand ridge field has a periodic nature of developing processes: the period of sediment accumulation by rivers during cold epoch with low sea level and the period of erosional formation by tidal currents during warm epoch of transgression. The river-sea interactive process in the area is closely related to the climate change; the rising and falling of the sea level is the detonating agent of the coast zone land-sea dynamic interactive processes. They can be summarized as “transgression-dynamic-sedimentation” processes.展开更多
An evolutionary model of sedimentary environments since late Marine Isotope Stage 3 （late MIS 3, i.e., ca. 39 cal ka BP） along the middle Jiangsu coast is presented based upon a reinterpretation of core 07SR01, new ...An evolutionary model of sedimentary environments since late Marine Isotope Stage 3 （late MIS 3, i.e., ca. 39 cal ka BP） along the middle Jiangsu coast is presented based upon a reinterpretation of core 07SR01, new correlations between adjacent published cores, and shallow seismic profiles recovered in the Xiyang tidal channel and adjacent northern sea areas. Geomorphology, sedimentology, radiocarbon dating and seismic and sequence stratigraphy are combined to confirm that environmental changes since late MIS 3 in the study area were controlled primarily by sea-level fluctuations, sediment discharge of paleo-rivers into the South Yellow Sea （SYS）, and minor tectonic subsidence, all of which impacted the progression of regional geomorphic and sedimentary environments （Le., coastal barrier island freshwater lacustrine swamp, river floodplain, coastal marsh, tidal sand ridge, and tidal channel）. This resulted in the formation of a fifth-order sequence stratigraphy, comprised of the parasequence of the late stage of the last interstadial （Para-Sq2）, including the highstand and forced regressive wedge system tracts （HST and FRWST）, and the parasequence of the postglacial period （Para-Sql）, including the transgressive and highstand system tracts （TST and HST）. The tidal sand ridges likely began to develop during the postglacial transgression as sea-level rise covered the middle Jiangsu coast at ca. 9.0 cal ka BP. These initially submerged tidal sand ridges were constantly migrating until the southward migration of the Yellow River mouth to the northern Jiangsu coast during AD 1128 to 1855. The paleo-Xiyang tidal channel that was determined by the paleo-tidal current field and significantly different from the modern one, was in existence during the Holocene transgressive maxima and lasted until AD 1128. Following the capture of the Huaihe River in AD 1128 by the Yellow River, the paleo-Xiyang tidal channel was infilled with a large amount of river-derived sediments from AD 1128 to 1855, causing the emergence of some of the previously submerged tidal sand ridges. From AD 1855 to the present, the infilled paleo-Xiyang tidal channel has undergone scouring, resulting in its modern form. The modern Xiyang tidal channel continues to widen and deepen, due both to strong tidal current scouring and anthropogenic activities.展开更多
Very limited modeling studies were available of the wave-induced current under the complex hydrodynamic conditions in the South Yellow Sea Radial Sand Ridge area（SYSRSR）. Partly it is due to the difficulties in esti...Very limited modeling studies were available of the wave-induced current under the complex hydrodynamic conditions in the South Yellow Sea Radial Sand Ridge area（SYSRSR）. Partly it is due to the difficulties in estimating the influence of the waveinduced current in this area. In this study, a coupled 3-D storm-surge-wave model is built. In this model, the time-dependent varying Collins coefficient with the water level method（TCL） are used. The wave-flow environment in the Lanshayang Channel（LSYC） during the ＂Winnie＂ typhoon is successfully represented by this model. According to the modelling results, at a high water level（HWL）, the wave-induced current similar to the long-shore current will emerge in the shallow area of the ridges, and has two different motion trends correlated with the morphological characteristics of the ridges. The wave-induced current velocity could be as strong as 1 m/s, which is at the same magnitude as the tidal current. This result is verified by the bathymetric changes in the LSYC during the ＂Matsa＂ typhoon. Thus, the wave-induced current may be one of the driven force of the ridge erosion and channel deposition in the SYSRSR. These conclusions will help to further study the mechanism of the ridge erosion and channel deposition in the SYSRSR.展开更多
The radial sand ridge system （RSRS） located at Jiangsu coast of China attracts much attention on its origin and mechanic of formation for its special structure and potential land resource. Due to complicated hydrody...The radial sand ridge system （RSRS） located at Jiangsu coast of China attracts much attention on its origin and mechanic of formation for its special structure and potential land resource. Due to complicated hydrodynamic condition, the Jiangsu RSRS is a hot debated on its potential sources, Yangtze River or Yellow River？ We collected ten sand samples from surface sediments along the west coast of Bohai Sea and Yellow Sea from the modern Yellow River estuary to Yangtze River estuary in summer, 2013. The samples are analyzed by method of detrital zircon age for source identification of the RSRS sediments. The U-Pb age spectra of detrital zircon grains of the samples show a wide range from Cenozoic to Late Archean with several age peaks. Comparing the age spectra between the Yangtze River and the Yellow River, the detrital zircons have younger age （〈100 Ma） group in the Yangtze River. These age distribution of the Jiangsu coastal RSRS sediments are similar to that of the Yangtze River, but different from the Yellow River. The samples located adjacent to the old Yellow River Delta show more wide-range age distribution, implying a compounded origination from the both rivers. Based on these findings it is proposed that, contrary to common opinion, the main sediment source of the Jiangsu RSRS is the Yangtze River, rather than the Yellow River. By implication, there should be evidence of hydrodynamic mechanics of oceanic currents and tidal motion. This aspect awaits confirmation in future research.展开更多
文摘Based on one-year wave field data measured at the south part of the radial sand ridges of the Southern Yellow Sea, the wave statistical characteristics, wave spectrum and wave group properties are analyzed. The results show that the significant wave height （H1/3） varies from 0.15 to 2.22 m with the average of 0.59 m and the mean wave period （Tmean） varies from 2.06 to 6.82 s with the average of 3.71 s. The percentage of single peak in the wave spectra is 88.6 during the measurement period, in which 36.3% of the waves are pure wind waves and the rest are young swells. The percentage with the significant wave height larger than 1 m is 12.4. The dominant wave directions in the study area are WNW, W, ESE, E and NW. The relationships among the characteristic wave heights, the characteristic wave periods, and the wave spectral parameters are identified. It is found that the tentative spectral model is suitable for the quantitative description of the wave spectrum in the study area, while the run lengths of the wave group estimated from the measured data are generally larger than those in other sea areas.
基金supported by the Ph.D. Programs Foundation of the Ministry of Education of China (Grant No.20070294026)
文摘According to a deformed mild-slope equation derived by Guang-wen Hong and an enhanced numerical method, a wave refraction-diffraction nonlinear mathematical model that takes tidal level change and the high-order bathymetry factor into account has been developed. The deformed mild-slope equation is used to eliminate the restriction of wave length on calculation steps. Using the hard disk to record data during the calculation process, the enhanced numerical method can save computer memory space to a certain extent, so that a large-scale sea area can be calculated with high-resolution grids. This model was applied to wave field integral calculation over a radial sand ridge field in the South Yellow Sea. The results demonstrate some features of the wave field： （1） the wave-height contour lines are arc-shaped near the shore; （2） waves break many times when they propagate toward the shore; （3） wave field characteristics on the northern and southern sides of Huangshayang are different; and （4） the characteristics of wave distribution match the terrain features. The application of this model in the region of the radial sand ridge field suggests that it is a feasible way to analyze wave refraction-diffraction effects under natural sea conditions.
基金Under the auspices of National Key Technology Research and Development Program(No.2012BAB03B01)National Natural Science Foundation of China(No.41273015,51278172,51478167)
文摘The Jianggang Harbour-centered radial sand ridge(RSR) is the largest sand body in the Yellow Sea. Its formation and evolution are of interest for scientists of various fields; however, the sediment provenance is uncertain. In this study, rare earth element(REE) geochemical compositions of the RSR sediments together with their potential sources are investigated to identify the provenance of the RSR sediments. The typical parameters((La/Yb)_N,(La/Sm)_N and(Gd/Yb)_N) as well as the upper continental crust-normalized patterns of REEs can only be associated with source rocks, and thus can be used as effective tracers for the origin and sources of sediments. However, the REE contents of sediments are affected by many factors, such as particle sorting and chemical weathering. Onshore RSR sediments are different in REE geochemical composition from offshore RSR sediments to some extent, suggesting that not all of the offshore RSR sediments have the same sources as the onshore RSR sediments. Meanwhile, the sediments adjacent to the northeast of Cheju Island and at Lian Island near the Lianyun Harbour were not the source of the RSR sediments due to their distinctive REE patterns, dEu,(La/Yb)_N,(Gd/Yb)_N and(La/Sm)_N. The Korean river sediments could be dispersed to the Jiangsu Coast slightly impacting the fine fractions of the RSR sediments, particularly the offshore RSR sediments. Additionally, geochemical comparisons show that the modern Yellow River was responsible for the onshore RSR sediments, whereas the sediment loads from the Yangtze River could serve as a major contributor to the RSR, particularly the offshore RSR. In addition, the offshore RSR could also be partly fed by an unknown source due to some high values of(La/Yb)_N,(La/Sm)_N and La contents differing from those of the Chinese and Korean river sediments.
基金Project supported by the National Natural Science Foundation of China (Grant No. 49236120).
文摘The results of simulated tidal current field, wave field and storm-induced current field are employed to interpret the depositional dynamic mechanism of formation and evolution of the radial sand ridges on the Yellow Sea seafloor. The anticlockwise rotary tidal wave to the south of Shandong Peninsula meets the following progressive tidal wave from the South Yellow Sea, forming a radial current field outside Jianggang. This current field provides a necessary dynamic condition for the formation and existence of the radial sand ridges on the Yellow Sea seafloor. The results of simulated 'old current field (holocene)' show that there existed a convergent-divergent tidal zone just outside the palaeo-Yangtze River estuary where a palaeo-underwater accumulation was developed. The calculated results from wave models indicate that the wave impact on the topography, under the condition of high water level and strong winds, is significant. The storm current induced by typhoons landing in the Yangtze River estuary and turning away to the sea can have an obvious influence, too, on the sand ridges. The depositional dynamic mechanism of formation andevolution of the radial sand ridges on the Yellow Sea seafloor is ' tidal current-induced formation-storm-inducedchange-tidal current-induced recovery' .
基金Project supported by the National Natural Science Foundation of China (Grant No. 49236120). Project coding: SCIEL 21198103.
文摘A sand ridge field of 22 470 km2 consists of fine sands and silts originally from the old Changjiang River sediment during the late Pleistocene period. Late Holocene sand stratum with its well-preserved larmnary bedding of more clay particles reflects the influence from the Yellow River. There are three genetic types of morphology of sand ridge field as follows: (i) reformed alluvial sandy bodies and old river valleys, located in the central and southern parts, formed from the end of Pleistocene to the present. (ii) Radiative current ridges and patrimonal valley type, located in the northeastern part, formed during the early or middle Holocene time. (iii) Eroded-depositional sandy bodies in the north and outer parts, and erosional trough in the north formed since the middle Holocene transgression.The sand ridge field has a periodic nature of developing processes: the period of sediment accumulation by rivers during cold epoch with low sea level and the period of erosional formation by tidal currents during warm epoch of transgression. The river-sea interactive process in the area is closely related to the climate change; the rising and falling of the sea level is the detonating agent of the coast zone land-sea dynamic interactive processes. They can be summarized as “transgression-dynamic-sedimentation” processes.
基金National Basic Research Program of China(973 Program),No.2013CB956500National Natural Science Foundation of China,Nos.40776023 & 40872107+3 种基金Comprehensive Investigation and Assessment in Jiangsu Offshore Area,Nos.JS-908-01-05&JS-908-01-101Special Fund for Marine Scientific Research in the Public Interest,No.201005006Special Fund for Land and Resources Research in the Public Interest,No.201011019China State-Sponsored Postgraduate Study Aboard Program,No.2011619035
文摘An evolutionary model of sedimentary environments since late Marine Isotope Stage 3 （late MIS 3, i.e., ca. 39 cal ka BP） along the middle Jiangsu coast is presented based upon a reinterpretation of core 07SR01, new correlations between adjacent published cores, and shallow seismic profiles recovered in the Xiyang tidal channel and adjacent northern sea areas. Geomorphology, sedimentology, radiocarbon dating and seismic and sequence stratigraphy are combined to confirm that environmental changes since late MIS 3 in the study area were controlled primarily by sea-level fluctuations, sediment discharge of paleo-rivers into the South Yellow Sea （SYS）, and minor tectonic subsidence, all of which impacted the progression of regional geomorphic and sedimentary environments （Le., coastal barrier island freshwater lacustrine swamp, river floodplain, coastal marsh, tidal sand ridge, and tidal channel）. This resulted in the formation of a fifth-order sequence stratigraphy, comprised of the parasequence of the late stage of the last interstadial （Para-Sq2）, including the highstand and forced regressive wedge system tracts （HST and FRWST）, and the parasequence of the postglacial period （Para-Sql）, including the transgressive and highstand system tracts （TST and HST）. The tidal sand ridges likely began to develop during the postglacial transgression as sea-level rise covered the middle Jiangsu coast at ca. 9.0 cal ka BP. These initially submerged tidal sand ridges were constantly migrating until the southward migration of the Yellow River mouth to the northern Jiangsu coast during AD 1128 to 1855. The paleo-Xiyang tidal channel that was determined by the paleo-tidal current field and significantly different from the modern one, was in existence during the Holocene transgressive maxima and lasted until AD 1128. Following the capture of the Huaihe River in AD 1128 by the Yellow River, the paleo-Xiyang tidal channel was infilled with a large amount of river-derived sediments from AD 1128 to 1855, causing the emergence of some of the previously submerged tidal sand ridges. From AD 1855 to the present, the infilled paleo-Xiyang tidal channel has undergone scouring, resulting in its modern form. The modern Xiyang tidal channel continues to widen and deepen, due both to strong tidal current scouring and anthropogenic activities.
基金Project supported by the National High Technology Research and Development Program of China(863 Program,Grant No.2012AA112509)the National Natural Science Fundation of China(Grant No.41373112)
文摘Very limited modeling studies were available of the wave-induced current under the complex hydrodynamic conditions in the South Yellow Sea Radial Sand Ridge area（SYSRSR）. Partly it is due to the difficulties in estimating the influence of the waveinduced current in this area. In this study, a coupled 3-D storm-surge-wave model is built. In this model, the time-dependent varying Collins coefficient with the water level method（TCL） are used. The wave-flow environment in the Lanshayang Channel（LSYC） during the ＂Winnie＂ typhoon is successfully represented by this model. According to the modelling results, at a high water level（HWL）, the wave-induced current similar to the long-shore current will emerge in the shallow area of the ridges, and has two different motion trends correlated with the morphological characteristics of the ridges. The wave-induced current velocity could be as strong as 1 m/s, which is at the same magnitude as the tidal current. This result is verified by the bathymetric changes in the LSYC during the ＂Matsa＂ typhoon. Thus, the wave-induced current may be one of the driven force of the ridge erosion and channel deposition in the SYSRSR. These conclusions will help to further study the mechanism of the ridge erosion and channel deposition in the SYSRSR.
基金supported by the National Natural Science Foundation of China (Nos. 41202154, 41273015)the National Key Technology Research and Development Program (No. 2012BAB03B01)the Fundamental Research Funds for the Central Universities (No. 2015B16914)
文摘The radial sand ridge system （RSRS） located at Jiangsu coast of China attracts much attention on its origin and mechanic of formation for its special structure and potential land resource. Due to complicated hydrodynamic condition, the Jiangsu RSRS is a hot debated on its potential sources, Yangtze River or Yellow River？ We collected ten sand samples from surface sediments along the west coast of Bohai Sea and Yellow Sea from the modern Yellow River estuary to Yangtze River estuary in summer, 2013. The samples are analyzed by method of detrital zircon age for source identification of the RSRS sediments. The U-Pb age spectra of detrital zircon grains of the samples show a wide range from Cenozoic to Late Archean with several age peaks. Comparing the age spectra between the Yangtze River and the Yellow River, the detrital zircons have younger age （〈100 Ma） group in the Yangtze River. These age distribution of the Jiangsu coastal RSRS sediments are similar to that of the Yangtze River, but different from the Yellow River. The samples located adjacent to the old Yellow River Delta show more wide-range age distribution, implying a compounded origination from the both rivers. Based on these findings it is proposed that, contrary to common opinion, the main sediment source of the Jiangsu RSRS is the Yangtze River, rather than the Yellow River. By implication, there should be evidence of hydrodynamic mechanics of oceanic currents and tidal motion. This aspect awaits confirmation in future research.
