The hydrocarbon reservoirs,which formed with the sediment supply of Altun mountain,have overall poor physical properties and strong anisotropy in the western margin of Qaidam Basin.For the purpose of predicting favorable reservoir distribution,it is urgent to carry out detailed division of the source-sink system.Using field outcrop and drilling core samples,comprehensive methods such as detrital zircon U-Pb isotopic dating,heavy mineral assemblages and sand body distribution are employed to conduct source-sink system analysis of the Upper Member of Lower Ganchaigou Formation of Paleogene in western margin of Qaidam Basin.As a result,five source-sink systems named as Qigequan,Shibei,Ganchaigou,Xianshuiquan,and Xiandong,respectively,are identified.They are different in heavy mineral assemblages and symbolic heavy mineral contents,and present different peak ages,peak age combinations and age spectrum patterns from each other.The age of sediment sources is mainly from 200 to 520 Ma,and the parent rocks is mainly composed of magmatic and metamorphic rocks.Affected by the supply of these sources,fan delta-sublacustrine fan systems are developed with greatly-varied scales in the study area correspondingly.It is shown that a single analytical method may lead to uncertainty in the division of source-sink systems.To achieve a more accurate understanding,multiple analytical methods should be combined and mutually validated.