| 我国南北方三角洲体系沉积特征的对比 |
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| 引用本文： | 李从先,陈刚,孙和平.我国南北方三角洲体系沉积特征的对比[J].沉积学报,1988,6(1):58-69. |
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| 作者姓名： | 李从先 陈刚 孙和平 |
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| 作者单位： | 同济大学海洋地质系 |
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| 摘 要： | 根据我国南北方三角洲沉积的特点,提出三角洲沉积体系的共性和特殊性。三角洲的共性包括基本相带的分布,垂直层序和海进河床充填层序;特殊性则是指三角洲砂体的组合、某些相指标,三角洲发育速度和改造程度。海进时溯源堆积在古河谷内形成了海进河床充填层序,而涨潮流和溯源堆积使该层序含某些海陆过渡相特征。南北方河流对已形成的三角洲层序改造程度有明显差异,这是由于南北方构造和气候条件不同所致。
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| 关 键 词： | 三角洲沉积体系 破体分布模式 海进河床充填层序 三角洲层序改造程度 |
| 收稿时间： | 1985-11-20 |
CORRELATION OF MODERN DELTAIC SEDIMENTARY SYSTEMS IN NORTH AND SOUTH CHINA |
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| Institution: | Department of Marine Geology, Tongji University |
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| Abstract: | The mid-seventies is the period of full bloom in delta sedimentation researches on large rivers abroad, but the papers on delta sedimentation were published in the late seventies and the early-eighties in China. Recently delta studies are concentrating on fan-deltas and transgressive channel-filling sequence. The deltaic sedimentation studies contribute a favourable condition for comparison between deltaic sedim-etary systems in North and South China, which includes their general and distinct charactereristics. The pattern of main facies, the vertical sequence and the transgressive channel-filling sequence belong to the former, and the distribution model of deltaic sand bodies, the vertical superimposition, the facies criteria, the development and the reworking belong to the later (Table 1). This paper deals with the transgressive channel-filling sequence, the progradational rate and the reworking of Table 1 Correlation of the delta systems in Soth and North China deltaic systems. The transgressive channel-filling sequence overlain by deltaic sequence is a fining-upward one with an erasional base surface and gravelly sand or sand in its lower part. It usually contains foraminifera with an upward increase in marineness and also contains marine authigenic minerals such as glauconite in subtropic zone of South China. The transgressive channel-filling sequences in delta areas of the Yangtse, Luanhe, Nanliujiang Rivers can be put in order of marineness. The marineness of transgressive channel-filling sequence in the coastal area is higher than that in the apical area of the Yangtse delta. That in the coastal area of the Luanhe delta is similar to the later, but the transgressive channel-filling sequence in its apical area absents marine microfossil. According to simulating tests, field observations and our recent measurements in the Yangtse, Nanliujiang and Qiantangjiang Rivers, there are the intrusion of sea water, flood tidal current, the backwater caused by datum rising and the retrogressive aggradation in lower reaches of river. Data from modern tidal estuaries show that the distances of retrogressive aggradation, backwater, flood tidal current and intrusion of sea water decrease in proper order. The retrogressive aggradation caused by postglacial sea-level rising formed the transgressive channel-filling sequence, whose characteristics were controlled by flood tidal current and intrusion of sea water. During the maximum transgression, transgressive channel-filling sequence without marine criteria could develop where retrogressive aggradation occured but no flood tidal current, such as the Luanhe fandelta area. This would also develop in the subtropic Nanliujiang delta area, but it was rewoked into a single normal river sequence by the river. |
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