海底沙脊地貌的研究现状及进展

综述了国内外海底沙脊地貌的研究成果、技术方法以及东中国海沙脊研究中存在的问题。弓京港辐射沙脊群成因的研究依然是国内沙脊研究的焦点;东海中北部陆架沙脊地貌形成时期(海进与海退期)、沉积类型(现代、残留及潮流沉积)、沉积动力及沉积模式等研究尚存在较多争议;古潮流场的研究尚未得到足够重视。最新多波束探测数据显示,东海中南部外陆架60 m以深海域广泛分布线状沙脊群,其规模较前人预测的更大、范围更广,与长江口外喇叭状地形区中的沙脊地貌在空间分布特征和发展趋势上均存在差异。未来若能在利用多波束探测数据的基础上,对单道地震剖面、柱状样品以及钻孔等获取的多种资料进行综合分析,将更有利于对沙脊地貌的精细结构、时空展布规律以及成因机制和演化模式的研究。

The present research situation and trend of submarine sand ridges geomorphology

Some study results and technologies of submarine sand ridges geomorphology are summarized,and several unfathomed issues of sand ridges on the eastern China seas are discussed in this paper.Currently,the search results from international famous periodicals(for example,Marine Geology and Sedimentary Geology) show that studies on the characteristics and causes of sand ridges are still the hot-topics of marine geology,and studies on the causes of radiate sand ridges off Jianggang,Jiangsu are the domestic focus.However,many topics of sand ridges on the north-central shelf of the ECS(East China Sea) are still in debate,such as the formation period(transgression or regression),deposit type(modern deposit,relict deposit or tidal deposit),deposition dynamics and deposition model.Although tidal currents play a key role on the development of sand ridges,ancient tidal currents are still not well studied and used quantificationally to analyze the causes of sand ridges in China.The latest multi-beam sounding data show that linear sand ridges are widely distributed on the outer shelf of the ECS,which are landward to the isobath of 60m and seaward to the water depth of 120m in the northeast and 150m in the southwest.The distributed scale of linear sand ridges on the shelf of the ECS is far wider than those from previous studies,and the three-dimensional structures and developing trends of linear sand ridges are different from that in the horn-shape area of Yangtze paleo-estuary,however,these sand ridges still have not been noticed fully and studied systematically.Finally,some advices for sand ridges study are put forward.The later studies on the elaborate structures and space-time distribution of sand ridges should be based on multi-kind data,such as the multi-beam sounding data,high-resolution single-channel seismic profile and the analyzing result of core and borehole etc.,studies on the evolution model and formation mechanism of sand ridges should be based on the results of ancient tidal currents and sea-level variations.