Basic Research for the Dynamics of Stratigraphic Sequence Formation

点击翻译按钮获取中文摘要

Temporal changes of depositional (i.e., accumulation) rate can be obtained for the Holocene when numerous and highly dense ^<14>C ages are determined for a given core. A smoothed curve on the diagram of age versus elevation is called a "depositional curve". Such "depositional curves" characterize temporal patterns of depositional rates in a wide range of depositional systems such as beach-shoreface, bay, delta, barrier, fluvial, and lake. These patterns are controlled by the following four factors: (1) a transgressive and regressive cycle for beach-shoreface and barriers systems; (2) a period of emergence for delta and bay systems; (3) depositional environments for fluvial systems; and (4) an absence of such variations for lake systems. Variations in coarsening-upward and/or fining-upward successions throughout a depositional sequence shows no relationship to depositional rate, even though they are characteristic of each environment in the depositional system. The "depositional curves" for different types of depositional systems appear to be important new data for the sequence-stratigraphic analysis of older deposits.