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四川盆地中西部(图1)上三叠统(即原“香溪群”)几个主要砂层的沉积环境,经与许多古今沉积对比,发现它们与现代河口地区的水(海)进河床充填砂体(简称水进河床砂体或水进河床沉积,下同)颇为相似,于是将其定为此种微相类型。所谓水进河床充填砂体,是水进期间沉积物填充河湖(或海)交汇地带的河道所形成。这种沉积体,近年来先后在我国长江口、珠江口、滦河口的现代沉积中被发现。据报导,非洲的尼日尔,美国的密西西比与拉瓦卡等河的河口附近亦有此类砂体存在。从许多古代沉积的实际资料看,在河湖(海)交汇地带,水进期的河道充填砂体更常见。
Sedimentary environments of the Upper Triassic (ie, “Xiangxi Group”) sandstones in the central and western Sichuan Basin (Fig. 1), in contrast to many ancient and modern sediments, have been found to enter the river bed with modern estuaries Filling sand bodies (referred to as water into the bed sand body or water into the riverbed deposition, the same below) is quite similar, so set it as this type of microfacies. The so-called water into the river bed filled sand body, is formed during the water into the sediment fill rivers and lakes (or sea) intersection zone of the river. In recent years, this sedimentary body has been found in the modern sediments of China’s Yangtze Estuary, Pearl River Estuary and Luanhe Estuary. It is reported that such sand bodies also exist near the estuaries of the Niger in Africa and the Mississippi and Lavaca in the United States. From the actual data of many ancient sediments, it is more common to see water-filled channel fill sand bodies in the confluence of rivers and lakes (sea).