ABSTRACT
Estuaries are most abundant and extensive during highstands of sea level in warm interglacial periods and rare or absent during lowstands of sea level in cold glacial periods. Rivervalley systems become inundated by seawater as sea level rises during interglacial episodes, creating coastal plain estuaries. The most recent rise in sea level due to progressive melting of ice commenced about 15,000 years ago when estuaries were small and rare, and from 15,000 to 6000 years ago, the rise in sea level exceeded 10 mm/year. The rapid landward advance of the sea at this time probably prevented the formation of extensive estuaries on the continental shelf. Estuaries are abundant and extensive during lowstands of sea level on epeirogenic coasts; they are rare and small during lowstands and on orogenic coasts. Estuaries are dynamic in space and time, their longevity being controlled primarily by sea-level changes and sedimentation.
