摘要
在浙北奥陶系文昌组和长江三角洲开敞型淤泥质海岸非潮道潮汐纹层研究的基础上，得出与国外同类研究相近的沉积率。现代海岸进积速度和潮坪沉积的观察及测试证明，上述沉积率是难以置信的。现代潮坪观测表明，潮汐纹层在形成过程中即包含着改造，所保留的纹层占应形成数的不到１０％，其余９０％以上被侵蚀。小型层序是风暴和平静天气的产物，为风暴层序，与大小潮周期无关。其地层中保留的数量不到应生成数的１０％，其余９０％被改造。小型层序被侵蚀，其中的纹层随之消失。致使潮坪层序中保存的纹层数仅为应形成数的０．２％。被改造的纹层和单层留下的仅是侵蚀面，即小间断。
Based on the study of tidal laminae of non tidal inlet in the Wenchang Formation of northern Zhejiang Province and at the muddy coast facing open sea in the Yangtze Delta region,the sedimentation rates have been calculated,which are close to that of similar study abroad.Field observation and research of coast pragradation rate and tidal flat sedimentation show that the calculated sedimentation rates are unreasonable.The investigation of present tidal flat in the Yangtze Delta reveals that tidal laminae are formed and reworked during a simidiurnal tidal cycle,and laminae preserved in the layer of sixteen days observation cover only 10% of that could be formed,other 90% have been eroded.The small sequence composed of sandy and muddy layers is a storm sequence,which is formed in the condition of alternation of storm and calm weather.Preservation of the small sequence covers about 10% of that could be formed,and other 90% are reworked.The laminae in the small sequence disappeared when the sandy and muddy layers eroded,so that the laminae preserved in tidal flat sequence are only 0 2% of that could be created.Reworked laminae and layer only have erosion surfaces,i.e.diastems.The attention should be paid to the sedimentary breaks,when we are doing high resolution study of the tidal deposits.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
1999年第2期11-18,共8页
Marine Geology & Quaternary Geology
基金
国家自然科学基金
关键词
潮汐沉积
沉积间断
长江三角洲
海洋沉积
tidal deposits sedimentary break Ordovician in northern Zhejiang the Yangtze Delta
