滹沱河平原段现代沉积物的成分与沉积环境

Composition and Sedimentary Environment of Recent Sediments of the Futou River on Plain Reach

Three fluvial reaches, upper, middle and lower, in the plain, within 180km in length, have been chosen for the study here. we had analysed light and heavy mineral composition and grain size distribution of sediments in the main channel, longitudinal bar, point bar and natural levee respectively. There are various material compositions, such as quartz, feldspar, litho-clast, heavy mineral, mica and matrix, in sediments of all sub-environments, but their percentage and grain-size distribution are changeable orderly with different sub-environments. From upper to lower reaches, longitudinally, the grain-size of sediments changed from coarser to finer; the content of quartz, feldspar and lithoclast from more to less; and the mineral maturity increased due to the increasing of transport distance and the weakening of hydrodyna-mic conditions. On the other hand, the cross changes from the main channel to longitudinal bar, point bar and natural levee are similar to longitudinal ones as mentioned above due to the increasing of depositional altitude and the weakening of hydrodynamic conditions.