Showing papers on "Sea-level curve published in 1985"

A sea-level curve for the Canadian Beaufort Shelf

Abstract: Radiocarbon-dated peat and peaty clay samples from geotechnical boreholes in the Canadian Beaufort continental shelf have been used to reconstruct a late Quaternary relative sea-level (RSL) curve. The samples were carefully selected and evaluated using palynological techniques, to ensure that reasonable age error limits could be given to each sample. The dated samples were then related to the local geological setting, using seismic profiles to determine the environment of deposition. The resulting data show a rise of 140 m in RSL since 27 000 years BP. A minor lowering of RSL at some time between 20 000 and 10 000 years BP is inferred from acoustic data. Contributions from basin subsidence, sediment loading, and consolidation account for 35 m of the total RSL rise. The RSL curve is interpreted in the light of recent models of the isostatic and eustatic responses of the Earth's crust at the Laurentide ice-sheet margin. Ice may have been more extensive during the middle Wisconsinan than previously thought a...

Synchronous Global Sequence Boundaries

Abstract: Sedimentary sequences in marine basins develop in response to relative changes in sea level. Sequence development in individual basins may be satisfactorily explained by a combination of tectonic subsidence and long-period changes in global sea level. It has been argued, however, that apparently synchronous shoreline shifts in widely separated basins require actual fluctuations in the global sea level curve with a period of 1-10 m.y. We suggest a mechanism for producing synchronous relative sea level changes in widely separated and geologically independent basins without producing changes in all basins, and without requiring short-period fluctuations in the global sea level curve. The same mechanism can produce nonsynchronous, but related, shoreline shifts in separate bas ns while the rate of global sea level change remains constant.