Cenozoic sediments, mainly carbonates, of the passive margin of Western Australia have been deposited during four cycles of sedimentation: late Paleocene to early Eocene, middle to late Eocene, late Oligocene to middle Miocene, and late Miocene and younger.
The Western Australian margin is suitable for a study of the cycles as it has not been deformed except for postrift downwarp, and the low relief of the hinterland has resulted in little deposition of terrigenous sediments during most of the Cenozoic.
The cycles may reflect large sea-level fluctuations probably caused by events of global significance. The inferred sea-level variation is greater than that caused by Quaternary glacial eustasy. Present-day sea level is close to the maximum sea level attained during the Cenozoic.