Modern to Ancient Barrier Island Dimensional Comparisons: Implications for Analog Selection and Paleomorphodynamics

摘要: Ancient barrier islands are poorly understood relative to other clastic depositional environments, despite being prominent features along modern coastlines and important for understanding transgressive shoreline deposits. A new dataset of ancient island dimensions (n=83 examples) addresses this knowledge gap with a quantitative analysis sand body including thickness (vertical), length (shore-parallel direction), width (shore-perpendicular direction). This deposits was compared planform measurements made (n=274), investigate possible scaling relationships aspects linkages. These nuanced challenging perform, first-pass comparisons show that should not be used as direct analogs systems. Nevertheless, results emphasize key preservation processes, the dimensional differences between formed over geologic versus time scales. Using methods outlined herein, appear 2-5x longer (p50 = 10.7 km; p50 20.0 km), 6-15x wider 1.2 7.3 km) than islands. We interpret indicate time-transgressive recording vertical amalgamation, growth by lateral accretion, progradation. When comparing single islands, do vary systemically examples, suggesting local accommodation dictates control. Gross length, width, too coarse robust paleomorphodynamic calculations, therefore more detailed sub-environment (e.g., upper shoreface delineation), improved facies models, is required before rigorous quantifications can generated. However, these initial trends which could leveraged, caution, in interim. As sea levels continue rise, motion will central predicting coastal change. Keywords: paleomorphodynamics, island, relationships, accommodation, shallow marine, dimension prediction, analog, reservoir,