Abstract:

The classic“Gilbert”delta is not a sole type of lake basin deltas,because the lake basin deltas though differ from those of marine basin in properties, they still have many common properties.Especially in particular situation,the deposition of deltas in marine basin is also an innegligible factor for lake basin deltas.The density of the water body of lake basins is close to that of rivers,but it may differs greatly from the river's or even exceeds that of marine basin.The effects of river of course played a decisive role in the formation of the lake basin deltas,but the effects of wave are very important.The transgression and regression of lake water even surpassed those of marine basin.Those deltasin special,such as steep slope deltas,transgres sive deltas of normal cycle andwave controlled deltas which are discovered in paleo-sediments and present sediments in succesion have provided material base for the classification in thispaper.In accordance with the combinations of the steepness or gentleness of slopes,transgression or regression of lakes and the controlling of waves or rivers,lake basin deltas can be divided into 8 end types so as to reveal their origin.