Session 3. Sequence Stratigraphy: Clastics (Continued)
"Session 3. Sequence Stratigraphy: Clastics (Continued)", Sequence Stratigraphy: The Future Defined, Bruce Hart, Norman C. Rosen, Dorene West, Anthony D’Agostino, Carlo Messina, Michael Hoffman, Richard Wild
Download citation file:
Sequence stratigraphy arose as a paradigm in stratigraphy following the introduction of the seismic method and its integration with genetic concepts linking seismic attributes to sedimentary dynamics. In its early shape, the sequence stratigraphy model was essentially rooted on the assumption that sea level cycles, in the form of basin-scale events, controlled the origin of depositional sequences. This founding assumption was vital for any revised version of sequence stratigraphy willing to maintain the status of “paradigm” and required evidence for “sequential” arrangement of progradational–aggradational–retrogradational patterns primarily governed by relative sea level.
Marine Quaternary stratigraphy provides plain evidence of such basin-scale sea-level control, albeit resulting in sequence shape and overall architecture substantially different from those of the basic sequence stratigraphy model. These differences have been settled by conceiving Quaternary sequences as atypical cases, commonly estranged from the debate on model refining. A reversal of this approach may be insightful, since Quaternary successions can be referred to sea-level curves of known periodicity and amplitude, in contrast with the older stratigraphy from which the basic model was derived.
Quaternary sequences indicate that the predominance of sea level (over other environmental factors) in shaping sequences depends on the duration of the full cycle and composing phases, scaled to its amplitude. Therefore, different sequence architectures may not represent fundamentally different models but rather a different balance between the main parameters of cycle duration, sea-level amplitude, and sedimentation rates. Changes in this balance may shift between end-member scenarios, ranging from greatly sea level-dominated (as in the Quaternary) to supply-dominated (as in large delta environments of pre-Quaternary greenhouse periods). This interpretative key allows us to explore different contexts all within a comprehensive model in which the control of sea level can vary significantly yet still coherently with the prediction potential of the model.