Sequence stratigraphy; seeking its possibility. Resolution potential of high-frequency depositional sequences in siliciclastic successions.

Abstract

Temporal variation in the timing and duration of high-frequency depositional sequences in the Late Pliocene and Pleistocene siliciclastic successions of the Kazusa Group in the Kazusa forearc basin of Japan and the Mississippi Fan sediments in the Gulf of Mexico is discussed, in terms of the interaction between glacio-eustatic sea-level changes and sedimentation rates. Although these two sedimentary basins are characterized by different tectonic and climatic settings, several common geological controls are evident on the development of high-frequency depositional sequences.A high sedimentation rate provides potential for developing high-frequency depositional sequences with duration, in general, less than 0.1m.y. under the influence of short-term glacio-eustatic sea-level changes. In particular, short-term glacio-eustatic sea-level falls are exaggerated in response to lowstands of the longer-term glacio-eustatic sea-level cycles. Duration of high-freqency depositional sequences during lowstands of the longer-term glacio-eustatic sea-level cycles is shorter than that in highstand stages. This shorter duration is influenced by a higher sedimentation rate and is sometimes less than 0.05m.y. In contrast, a low sedimentation rate and/or highstands of the longer-term glacio-eustatic sea-level cycles have given rise to high-frequency depositional sequences with duration up to about 0.5m.y., even though short-term glacio-eustatic sea-level changes with periodicity about 0.05 to 0.04m.y. were pervasive. This is interpreted to indicate that timing and duration of high-frequency depositional sequences is controlloed not only by interaction of superimposed short-and long-term glacio-eustatic sea-level changes but also by temporal variation in a sedimentation rate at an active plate margin as well as at a passive plate margin.