Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis ...Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis identifies two major factors that account for the total variability in most common minerals: 1) based on the relationship of quartz, hornblende, actinolite, micas, and authigenic pyrite, 41.55% of the variability is related to sediment sources; 2) based on the relationship of epidote, garnet, sphere, and ilmenite, 23.21% can be related to strong hydrodynamic conditions that control transport and sedimentation. By comparing mineral compositions of river waters in the study area, the following four mineral provenances can be identified. The Qingdao-Laoshan nearshore area has a quartz-feldspar-epidote-hornblende-limenite-limonite-sphene assemblage, which is largely attributed to relict sediment and coastal erosion. The Jimo-Haiyang nearshore area has a quartz-feldspar-hornblende-epidote-limonite-mica-actinolite assemblage, derived largely from the Wulong River and Rushan River, and is also affected by the Huanghe River, while the Qianliyan Island area in the deeper offshore area separated by a mud belt has a similar assemblage. The Haiyang-Rushan nearshore area has a quartz-feldspar-hornblende-epidote-micas-limonite assemblage, indicating multiple sources from the Rushan River, the Wulong River, the Huanghe River, and coastal erosion. The central area, located in an eddy center, has a mica-authigenic pyrite-hornblende-quartz-feldspar assemblage, indicating multiple sources dominated by Huanghe River distal sediments.展开更多
With the combination of historical data, field observations and satellite remotely sensed images (Landsat TM/ ETM+ and CBERS), changes in Huanghe (Yellow) River estuary since 1996 when artificial Chahe distributary wa...With the combination of historical data, field observations and satellite remotely sensed images (Landsat TM/ ETM+ and CBERS), changes in Huanghe (Yellow) River estuary since 1996 when artificial Chahe distributary was built up were studied, mainly including water and sediment discharge from the river, tides, tidal currents, suspended sediment diffusion, coastline changes and seabed development. During following six and half years (up to the end of 2002), runoff and sediment loads into the river mouth declined dramatically. At the beginning of the re-routing, abundant sediment loads from the river filled up nearshore shallow water areas so that the newborn delta prograded quickly. With rapid decrease of sediment loads transported to the estuary, the delta retrograded. In 1997, subaerial tip of the abandoned delta receded 1.5km; its annual mean recession rate was about 150 m in following years. In addition, marine dynamic condition near the artificial outlet had also changed. Under the interaction of ocean and river flow, most of incoming sediment loads deposited in the vicin- ity of the outlet. Seabed erosion occurred at the subaqueous delta front. Between 1999 and 2002, erosion thick- ness averaged at 0.3 m in the subaqueous delta of 585.5 km2.展开更多
基金the National Natural Science Foundation of China (Nos. 41376079, 41406081 and 41506107)Marine Geology Survey Project (Nos. GZH200900501 and GZH201100203)the Basic Fund of Ministry of Science Foundation of China (No. 2013FY112200)
文摘Detrital minerals of 137 offshore and 22 river sediment samples collected from Qingdao coastal areas have been analyzed. Four mineral assemblage provinces can be classified by Q-mode cluster analysis. Factor analysis identifies two major factors that account for the total variability in most common minerals: 1) based on the relationship of quartz, hornblende, actinolite, micas, and authigenic pyrite, 41.55% of the variability is related to sediment sources; 2) based on the relationship of epidote, garnet, sphere, and ilmenite, 23.21% can be related to strong hydrodynamic conditions that control transport and sedimentation. By comparing mineral compositions of river waters in the study area, the following four mineral provenances can be identified. The Qingdao-Laoshan nearshore area has a quartz-feldspar-epidote-hornblende-limenite-limonite-sphene assemblage, which is largely attributed to relict sediment and coastal erosion. The Jimo-Haiyang nearshore area has a quartz-feldspar-hornblende-epidote-limonite-mica-actinolite assemblage, derived largely from the Wulong River and Rushan River, and is also affected by the Huanghe River, while the Qianliyan Island area in the deeper offshore area separated by a mud belt has a similar assemblage. The Haiyang-Rushan nearshore area has a quartz-feldspar-hornblende-epidote-micas-limonite assemblage, indicating multiple sources from the Rushan River, the Wulong River, the Huanghe River, and coastal erosion. The central area, located in an eddy center, has a mica-authigenic pyrite-hornblende-quartz-feldspar assemblage, indicating multiple sources dominated by Huanghe River distal sediments.
基金The work was supported by the National High-tech Research and Development Program of China (863 Program, No. AA633010-05) and key project of Natural Science Foundation of China (No. 50339050)
文摘With the combination of historical data, field observations and satellite remotely sensed images (Landsat TM/ ETM+ and CBERS), changes in Huanghe (Yellow) River estuary since 1996 when artificial Chahe distributary was built up were studied, mainly including water and sediment discharge from the river, tides, tidal currents, suspended sediment diffusion, coastline changes and seabed development. During following six and half years (up to the end of 2002), runoff and sediment loads into the river mouth declined dramatically. At the beginning of the re-routing, abundant sediment loads from the river filled up nearshore shallow water areas so that the newborn delta prograded quickly. With rapid decrease of sediment loads transported to the estuary, the delta retrograded. In 1997, subaerial tip of the abandoned delta receded 1.5km; its annual mean recession rate was about 150 m in following years. In addition, marine dynamic condition near the artificial outlet had also changed. Under the interaction of ocean and river flow, most of incoming sediment loads deposited in the vicin- ity of the outlet. Seabed erosion occurred at the subaqueous delta front. Between 1999 and 2002, erosion thick- ness averaged at 0.3 m in the subaqueous delta of 585.5 km2.
