Sandy conglomerates in steep slopes are characterized as various fan types

abundance of provenances

and high deposition rate

and the provenance supply capacity is one of the main factors controlling sandy conglomerate scale and its sedimentary system.However

the quantitative study of provenance supply is always a weak point which constrains the study of sedimentary system.In order to address the problem

we worked out the provenance supply index with weighted average of parameters which have positive and inverse relation with provenance supply rates.The calculation was based on the study of conglomerate content

ratio of sand and formation

lithologic index

development degree of interbed(frequency

thickness

percentage)

mineral content

granularity distribution.And the results show that (1) the areas with high provenance supply indexes are mainly distributed in the north

close to the downthrown side of Chengnan fault

along large faults in the form of apron; (2) the provenance supply capacity determines the development scale of sandy conglome-rates:the distribution patterns and scales of sandy conglomerates beside plate-

shovel-

ladder- and slope-shaped boundary faults vary with the varying provenance supply capacities.In addition

a combination of the provenance supply capacity and depth of water controls the types of sedimentary facies.With the change of these two factors

the studied area has developed such sedimentary facies as fluvial facies

alluvial fan

carbonate rock

delta

fan delta

turbidite fan

sublacustrine fan

coastal subsea apron and so on.