Contrasting textures, provenances and structures of sediment in the inner shelf south of Shandong Peninsula, western South Yellow Sea
Contrasting textures, provenances and structures of sediment in the inner shelf south of Shandong Peninsula, western South Yellow Sea
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南黄海西部山东半岛南部内陆架沉积物结构、物源和结构对比
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通讯作者：
Gang Xu
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作者：
Gang Hu;Peter D. Clift;Kehui Xu;Yong Zhang;Shipu Bi;Gang Xu
虽然对黄河水下三角洲远缘泥楔的研究较多，但对南黄海内陆架黄河泥楔西南端的研究较少。利用3,000 km的高分辨率浅地层地震剖面和137个表层沉积物样品，对南黄海西部山东半岛以南内陆架沉积物的结构、物源和构造进行了研究。研究结果表明，山东半岛南部内陆架沉积物可分为砂、粉砂、桑迪粉砂、泥砂、泥及其它10种类型。约60%的研究区被粉土和桑迪粉土覆盖，形成一个“U”形带。假设黄河水下三角洲沉积物质地较细，而当地小河流沉积物质地较粗，则表明存在两种不同的沉积物来源。位于半岛南岸的老山头岬以东，沉积物主要来自黄河，全新世沉积物在水深约10 m处达~15 m，其均匀的表层沉积物格局受黄海沿岸流（YSCC）、黄海暖流（YSWC）和沿岸流控制。而崂山头以西则主要为流经山东半岛的当地小河流沉积物，沉积厚度不超过5 m，其混合沉积物受到强潮汐和沿岸流的改造。崂山头岬向海延伸的部分是沿岸流携带泥沙聚集的有效场所。研究还揭示了黄河细颗粒泥沙和当地小河流粗颗粒泥沙长距离输移的相对贡献。
Although many studies have been performed on the mud wedge of distal part of Yellow River subaqueous delta, little is known about southwestern terminus of Yellow River mud wedge in inner shelf of South Yellow Sea. We use ~3,000 km of high-resolution subbottom seismic profiles and 137 surficial sediment samples to study sediment textures, provenances and structures in the inner shelf south of Shandong Peninsula in western South Yellow Sea. Our results show that sediment in the inner shelf south of Shandong Peninsula can be categorized into ten types, including sand, silt, sandy silt, muddy sand, mud and others. About 60% of our study area is covered by silt and sandy silt, which forms a “U” shaped zone. Assuming a fine texture of sediment of Yellow River subaqueous delta and a relatively coarse texture of sediment from local small rivers, our results indicate two contrasting sediment sources. East of Laoshantou headland which is on the southern coast of Peninsula, the sediment is mainly from the Yellow River, Holocene deposition reaches ~15 m thick in about 10 m deep water, and the its homogeneous surficial sediment pattern is controlled by the Yellow Sea Coastal Current (YSCC), the Yellow Sea Warm Current (YSWC), and the longshore current. West of Laoshantou, however, sediment from local small rivers draining the Shandong Peninsula plays an important role, depositional thickness is no more than 5m thick, and its mixed sediment is re-worked by strong tides and longshore currents. The seaward extension of Laoshantou headland seems to act as an effective sediment trap to accumulate sediment carried by longshore currents. Out study also reveals relative contributions of long-distance transport of fine-grained sediment from Yellow River and coarse-grained sediment from line-sourced local small rivers.