Abstract

Dissimilarity in relations between thickness, duration, and accumulation rate in Holocene sections, metre-scale Phanerozoic cycles, and epoch-interval Phanerozoic sequences reflects variation in the distribution of depositional and hiatal time at different scales of observation. Modern accumulation rates are strongly dependent on duration of deposition; lower rates correspond to longer durations. Phanerozoic cycle thicknesses are similar to those of Holocene sections, suggesting that both formed while filling similar amounts of accommodation space. However, accumulation rates of Phanerozoic cycles and sequences are about two orders of magnitude less than in modern settings, and they show neither strong dependence on duration of accumulation nor significant variation over Phanerozoic time. Hence, net accumulation is primarily controlled by regional subsidence rate. These relations also allow for determination of that fraction of cycle period recorded as rock and that corresponding to hiatal time at intercycle boundaries. Depending on subsidence rate and amount of compaction, most cratonic carbonate units accumulated over 3% to 30% of the time represented by sequences in which they occur.

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