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Temporal and spatial variations of the Huanghe River mouth bars

Acta Oceanologica Sinica 2005年第2期24卷 43-56页

作者： YANGZuosheng ZHANGYong LIUZhan WEIHelong HEShufeng InstituteofEstuarineandCoastalStudies OceanUniversityofChinaQingdao266003China UniversityofPetroleum（EastChina） Dongying257061China InstituteofEstuarineandCoastalStudies OceanUniversityofChinaQingdao266003China／／QingdaoInstituteofMarineGeologyChinaGeologicalSurveyQingdao266071China qingdaoinstituteofmarinegeology ChinaGeologicalSurveyQingdao266071China

On the basis of the bathymetric records of 371 survey sections in the present Huanghe mouth area from 1996 to 2001, the temporal and spatial variations of the Huanghe mouth bars were studied by using GIS technology. The variation of the mouth bars is closely related to the water and sediment discharges from the Huanghe River to the sea that has been decreasing drastically in recent years, and to coastal hydrodynamic regimes. The characteristics of the mouth bars are unique in contrast with those of other estuaries in the world. (1) The mouth bars of the Huanghe River consist of many small sandbars. Usually the sandbars are of ellipse-shape with the long axis of about 1~6 km, and short axis of about 1~4 km. The long axis is parallel to the principal direction of tidal current, and the short axis is variable, depending on the local dynamics. The crest of the sandbars is only about 0.4 m below the water surface at low tide. They are distributed within an area of 20 km2, not far from the river mouth area. The present mouth bars are in small-medium size, quite different from the large one formed during the 1970s and 1980s, when the river sediment discharge was several times larger than that after 1996. (2) The scale of a river mouth bar is related to the river discharge of that year. In 1997 sediment discharge from the Huanghe River was 42 Mt, and the mouth bar consisted of several small scattered sandbars. In 1998 the size of mouth bars was much larger than that in 1997, as the sediment discharge from the Huanghe River increased to 363 Mt. Variation of the mouth bars largely depends on the sediment discharge with a correlation coefficient of 0.78. The calculation of the volume of the mouth bar area shows that about 30%~40% of the river's into-sea sediment is deposited in the mouth bar area. (3) Compared with other large estuaries in the world, the Huanghe mouth bars have three unique features in responding to its high sediment concentration: small size, steep slope gra

关键词： Huanghe mouth bars temporal and spatial variations mechanism of formation

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A new ichnotaxon of fossil bird track from the Early Cretaceous Tianjialou Formation (Barremian- Albian), Shandong Province, China

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Chinese Science Bulletin 2005年第11期50卷 1149-1154页

作者： LIRihui MartinGLockley LIUMingwei qingdaoinstituteofmarinegeology ChinaGeologicalSurveyQingdao266071China UniversityofColoradoatDenver EO.Box173364DenverColoradoUSA FourthGeologicalandMineralResourcesSurveyofShandong Weifang261021China

A single set of 5 bird tracks was discovered in the Tianjialou Formation (Barremian-Albian) of Junan County, Shandong Province, China. After careful study we infer that it is a new type of bird tracks, and a new ichnoge- nus was erected and the name Shandongornipes was given. The characteristics of the new bird track are as follows: Moderately large tetradactyl footprints with well-developed hallux impression. Track width (about 5.8 cm) almost equal to track length (excluding hallux); total length of track (in- cluding hallux) 8.7 cm. The digit impressions are slender, with distal ends showing long sharp claw marks. Hallux pos- teriorly-directed, and hallux impressions well-developed. Digits II, III and IV point anteriorly, exhibiting mesaxonic asymmetry: divarication angle between II and III much lar- ger than that of III and IV, the former ranging from 91° to 118°, and the latter less than 30°. Divarication between digits II and IV ranging from 128° to 142°. Without web structures. Digital pads recognizable, usually at least three in digits III and IV, but sometimes only two due to preservation. The trackway shows slight positive (inward) rotation of feet. The bird tracks occur in association with abundant dinosaur tracks, and are believed to have formed in flood plain environments.

关键词：四趾鸟类足迹鸟类化石白垩纪时代中国山东

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Features of Clay Minerals in the YSDP102 Core on the Continental Shelf of the Southeast Yellow Sea

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Journal of Ocean University of China 2004年第2期3卷 201-207页

作者： JIANGXuejun QUGaosheng LIShaoquan qingdaoinstituteofmarinegeology Qingdao266071P.R.China

Ninety-eight clay mineral samples from the YSDP102 core were analyzed by x-ray diffractometer to study the four clay minerals: illite, chlorite, kaolinite and smectite. Twenty-eight samples had been analyzed on the laser particle-size analyzer to reveal the particle features of the sediments. Distribution of the clay minerals and the particle characteristics in the YSDP102 core show that the core experienced three different depositional periods and formed three different sedimentary intervals due to different sediment sources and different depositional environments. Features of the clay minerals and the heavy minerals in the YSDP102 core indicate that coarse-grained sediments and fine-grained sediments result from different sources. The Yellow Sea Warm Current has greatly influenced the sedimentary framework of this region since the current’s formation.

关键词： clay minerals sediment sources Yellow Sea Warm Current depositional environment

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Causes of Land Loss in Tuvalu,a Small Island Nation in the Pacific

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Journal of Ocean University of China 2005年第2期4卷 115-123页

作者： XUEChunting qingdaoinstituteofmarinegeology Qingdao266071P.R.China

Studies on land loss in Tuvalu reveal the following findings. Although both sea level rise and coastal erosion can cause land loss in the tropic Pacific oceanic islands, their mechanisms are different. When sea level rises, the low elevation coastal zone submerges and the erosion datum plane rises, the beach process progresses normally as always, resulting in no beach sediment coarsening. When the sea level is stable, coastal erosion removes finer sediment from reef flat, beach and land, resulting in beach sediment coarsening. The human-induced coastal erosion in the tropic Pacific oceanic islands has the following features. 1) Erosion occurs or intensifies immediately after inappropriate human activities. 2) It occurs near the places having human activities and places related to the above places in sediment supply. 3) It often occurs on original prograding or stable coasts (on lagoon coasts for atolls) because there are more coastal engineering projects and other human activities on such coasts. 4) It is chronic, covering a long period of time. The coastal geological events in Tuvalu islands do not accord with the features resulted from sea level rise but do accord with the features resulted from coastal erosion, particularly from human-induced erosion. The land loss in Tuvalu is mainly caused by inappropriate human activities including coastal engineering and aggregate mining, and partly caused by cyclones. Moreover, all recent measurements (satellite altimetry,thermosteric sea level data and tide observations) so far have not been able to verify any sea level rise around Tuvalu islands.

关键词： sea level rise land loss coastal erosion artificial channel aggregatemining

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Natural and Artificial Connections between Atoll Islets in the Pacific,Their Process and Environmental Impact

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Journal of Ocean University of Qingdao 2003年第2期2卷 195-200页

作者： XUEChunting RussellHoworth qingdaoinstituteofmarinegeology Qingdao266071P.R.China SouthPacificAppliedGeoscienceCommission（SOPAC） SuvaFiji

Three types of natural connection between atoll islets are described. Causeway, as an artificial way of connecting islets, makes a connection to be completed in a few months. In this case shore adjustment becomes more vigorous than that in natural conditions, resulting in lagoon shore erosion. A causeway without short bridges or culverts should be built close to the lagoon shore to reduce lagoon shore erosion. A causeway-crossing channel assemblage is the worst type among all of the connection engineering constructions because the crossing channel traps sediment and further transports it out of the channel, resulting in long period coastal erosion. Reforming Nippon Causeway in Tarawa Atoll, Kiribati by simple means will stop sand loss, reduce shore erosion and greatly upgrade its stability.

关键词： atoll environment impact causeway coastal erosion

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Environmental Impact of Artificial Harbors in Tropic Pacific Oceanic Islands

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Journal of Ocean University of China 2004年第1期3卷 99-105页

作者： XUEChunting RussellHoworth HEChaoxiong qingdaoinstituteofmarinegeology Qingdao266071P.R.China SouthPacificAppliedGeoscienceCommission（SOPAC） SuvaFiji GuangzhouMarineGeologicalSurvey Guangzhou510000P.R.China

For loading and unloading of boats or ships round the clock, the access channel and its expanded part-a port are excavated on the lagoon and ocean reef flats in the tropic Pacific oceanic islands. Without moles, the access channel port traps sediment and further transports it to the ocean or lagoon, resulting in coastal erosion. The wide uneven reef flat with a large catchment area tends to cause the formation of tide currents in the channel port, while strong waves on the narrow even reef flat can give rise to rip currents. An access channel port with a mole on one side or two moles on both sides results in less erosion. A model is recommended as an artificial harbor on the ocean coast, which is an excavated port surrounded by a mole, connected with the ocean by an access channel and with the shore by a bridge shaped pier.

关键词： artificial channel port sediment trap longshore current coastal erosion

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