| Sequence stratigraphy is a widely used model for organizing stratigraphic successions. Extending this model quantitatively must involve constraining the time dynamics of stratal formation and better recognition of autogenic effects in stratal architecture. This dissertation is an initial evaluation of these two issues using experimental subsiding basins, which allows close study of stratal accumulation in a controlled depositional environment.; Evaluation of experimental stratigraphy shows that the stacking arrangement of the preserved bounded strata is a good time-averaged representation of the known mass-balance history, supporting a core sequence stratigraphic tenet. Depositionally based sequence stratigraphic surfaces closely parallel topographic surfaces (time lines) and are robust stratigraphic recorders of external forcing. Experimental observations of erosionally based stratal surfaces diverge from the conceptual sequence stratigraphic model in that these surfaces do not have geomorphic equivalence: channel processes continually modify the stratigraphic surface, producing a highly composite, time-transgressive structure.; Incised valleys are the primary erosional element in sequence stratigraphy and produce prominent erosional disconformities. Experimental measurements combined with a new numerical model show a strong tendency for valleys to widen downstream due to increases in sediment flux. Further, valley degradation and widening are enhanced by increasing either relative sea-level fall or initial offshore water depth. The latter is set by initial topography.; Autogenic controls on deposition are not formally included in sequence stratigraphy, but act as a noisy filter on stratigraphic recording, and govern stratigraphic architecture at small scales. We study autogenic depositional mechanics in two experiments. In the first, shoreline regression persistency is quantitatively linked to channel network migration. Migration and persistence time scales are reduced (by factors of 3 and 2, respectively) by base-level rise. Variable autogenic process rates are not statistically reflected in the shoreline structure; rather they demonstrate a form of decoupling between delta kinematics and geometry.; In the second study, hydraulically subcritical flow leads to relatively greater flow mobility by introducing bedforms (high-frequency bed roughness elements). Frequent scouring of the active layer creates a strong scour-fill bias in the deposit that obscures the surface flow organization. Otherwise, subcritical flow does not fundamentally change the process of stratal generation. |
