冰消期海侵进程中南黄海潮流沙脊的演化模式  

EVOLUTION MODEL FOR SOUTH YELLOW SEA TIDAL SAND RIDGES DURING TRANSGRESSIONS IN DEGLACIATION

作　　者：杨子赓[1] 王圣洁[1] 张光威[1] 李绍全[1] 刘健[1] 

机构地区：[1]青岛海洋地质研究所,青岛266071

出　　处：《海洋地质与第四纪地质》2001年第3期1-10,共10页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金重点资助项目 (4973 62 10 )

摘　　要：南黄海东侧底形资料、浅地层剖面和 YSDP- 10 2钻孔揭示了冰消期海侵初期的古潮流沙脊群 ;南黄海QC2孔上部岩心又揭示了全新世中期的埋藏古潮流沙脊群 ;842 2柱状岩心补充了若干现代南黄海沙脊群——苏北岸外辐射状沙脊群的特征。根据 1 4 C测年、ESR测年及突变事件的分析 ,获得了不同时期沙脊形成的年代标尺 ,并获得以下结论 :(1)沙脊沉积在层序地层中属上海侵体系域 (U TST) ,其发育与海平面密切相关 ,最佳发育深度在- 2 0～ - 30 m水深范围内 ,很少有超过 - 40 m者。南黄海沙脊群随着陆架海侵进程自东向西跃迁 ,沙脊群广泛发育预示海平面的相对稳定或小幅度波动期 ;海平面急剧上升期实现了沙脊群的跃迁。南黄海沙脊演化可划分为 3期 :早期 (约 12～ 9ka)是据新仙女木期 (YD)的海平面波动 ,以南黄海东侧古潮流沙脊群为代表 ;中期 (约 6 .3～4ka)包括了中全新世高温期气候突然衰退事件 (MHCR)的海平面波动 ,南黄海中部 QC2孔揭露的埋藏潮流沙脊是这一期的代表 ;晚期为 2 ka至今的海平面缓慢波动期 ,以现代苏北岸外辐射沙脊群为代表。 (2 )潮流沙脊沉积物特征反映了水动力条件的变化。早期沙脊处于强动力作用下 ,随着海侵范围扩大 ,形成沙脊的动力条件愈来愈弱。(3)南黄海、东海与北黄海沙脊发育与演化?Ancient tidal sand ridges during the early stage of transgressions in deglaciation are known from bed form data got from the east side of the South Yellow Sea,shallow stratigraphic profile and drill YSDP 102.The upper part of drill QC2 in the sea also reveals buried tidal sand ridges in the middle time of Holocene.And column core 8422 has complemented many characteristics of modern South Yellow Sea sand ridges-radiant sand ridges off North Jiangsu Province.According to 14 C and ESR dating as well as analysis of abrupt events,we get time scales for different periods of sand ridges and come to the following conclusions:(1)Sand ridge deposits belong to upper transgression system terrain(UTST) in sequence strata,and their development is closely related to sea level with the optimum development depth between 20～ 30 m below sea level and there is very few to develop at a depth over 40 m.The dune ridges moved from east to west with the process of continental shelf transgressions and the evolution can be divided into 3 stages:early stage(about 12～9 ka)saw the formation of tidal sand ridges in the east side of the South Yellow Sea due to the sea level fluctuations in Younger Dryas;the middle stage(about 6.3～4 ka)was represented by sea level changes caused by middle Holocene Hypsithermal periods sudden climatic retrogression events(MHCR),which gave birth to buried sand ridges revealed by drill QC2 in the middle of the South Yellow Sea;and the late stage was a period of slow sea level fluctuation from 2 ka to present when the radiant ridges were formed off North Jiangsu Province coast.(2)Tidal sand ridges deposits have reflected hydrodynamic conditions.Sand ridges in the early time of formation are under strong dynamic conditions,but the dynamic conditions for the formation of dune become weaker and weaker with the expansion of transgressions.(3)Sand ridges in the South Yellow Sea,East China Sea and North Yellow Sea have similar histories of development and therefore the relation model between the So

关 键 词：冰消期 海侵进程 海平面变化 潮流沙脊 演化模式 黄海 

分 类 号：P736.21[天文地球—海洋地质]