中国的网状河流体系

网状河流是由低坡降、深且窄、重复分汊合并的多河道系统及大片的泛滥平原所组成的一种特殊的河流类型,研究尚待深入。中国的许多河流发育了网状河段,其中包括黑龙江、松花江和长江等一些大型河流以及许多中、小型河流。按照地理和构造背景的不同可以把它们分为平原地区网状河流、山谷网状河流、入湖三角洲平原网状河流和入海三角洲平原网状河流四大类。这四类网状河流在形成机理、地貌和沉积特征等方面有所不同。研究古代沉积,对于研究油气储集体来说,进一步地了解网状河流,特别是研究平原地区和三角洲平原上的网状河流具有重大的意义。

ANASTOMOSING FLUVIAL SYSTEMS IN CHINA

Anastomosing rivers consist of low-gradient, narrow and deep, multiple channels which branch and rejoin repeatedly, and floodplains lying between the channels. This special kind of rivers is not so well understood as meandering and braided rivers. Nevertheless, many Chinese rivers have anastomosing reaches, including some large rivers such as Heilong Jiang, Songhua - Jiang and Yantze River, and many of small scale river. According to their tectonic and geomorphic settings, these anastomosing fluvial systems can be grouped into four types: mountain valley anastomosing river, plain anastomosing river, lacustrine deltaplain anastomosing river, and marine deltaplain anastomosing rivers. Each of these four types is different in terms of genesis, morphology and sedimentology. Plain anastomosing rivers seem to form in the last stage of continental sedimentary basins while lacustrine delta-plain anastomosing river systems are likely related to sequence stratigraphical highstand systems tracts.