Modern and ancient sedimentary basins: Comparative accumulation rates

Abstract

The rate at which sedimentary fill accumulates in both modern and ancient depositional basins is related to plate tectonic setting, among other factors. The tectonic setting of any basin can be specified in terms of type of substratum (oceanic, continental, or transitional), proximity to plate margins (mid-plate versus interplate), and the nature of the nearby plate margins (constructive, destructive, and conservative). Midplate basins generally accumulate sedimentary fill at much slower rates than basins located along or proximal to plate margins. Midplate basins situated entirely above a single substratum type (that is, cratonic basins) ordinarily accumulate sediment cover very slowly (usually less than 0.006 m/1,000 yr), although more rapidly subsiding negative areas within continental blocks and near their margins adjacent to orogenic areas exhibit higher rates. Midplate basins that straddle both continental and oceanic crust (modern continental terraces and rises, ancient miogeoclines and the nonorogenic portion of ancient eugeosynclines) accumulate sediment several times as rapidly as cratonic basins (generally 0.01 to 0.04 m/1,000 yr). Accumulation rates for sediment deposited in basins along or adjacent to plate margins almost invariably exceed 0.04 m/1,000 yr and are commonly much higher than the accumulation rates for midplate basins. However, the accumulation rates for basins along convergent, divergent, and conservative plate margins are not sufficiently different from one another to be distinctive. Sediment filling the successor basins that commonly develop over the site of sutured plate margins has accumulation rates comparable to those of interplate basins.