Print Email Facebook Twitter Grain size fractionation by process-driven sorting in sandy to muddy deltas Title Grain size fractionation by process-driven sorting in sandy to muddy deltas Author van der Vegt, H. (TU Delft Applied Geology; Deltares) Storms, J.E.A. (TU Delft Applied Geology) Walstra, Dirk Jan R. (Deltares) Nordahl, Kjetil (Equinor ASA) Howes, Nick C. (MathWorks, Natick) Martinius, A.W. (TU Delft Applied Geology; Equinor ASA) Date 2020 Abstract Modern and ancient analogues are often consulted by geologists to help understand subsurface systems. While modern analogues provide information on the areal relationship between facies, ancient systems provide detailed data on the vertical facies variations, typically along a two-dimensional outcrop. Combining data from modern and ancient systems effectively requires translating areal morphology, which is often still evolving, to the related sediments preserved in three dimensions. Process-based models simulate both depositional processes while preserving stratigraphy. These models can be employed to unravel the relationship between sediment supply and preserved deposits in natural systems and to help integrate field data. Four synthetic deltas were modelled using different sediment supply compositions, from coarse to very fine sand systems. The resultant sedimentary deposits are classified into architectural elements, and the grain size composition of each architectural element is studied over time. Facies that are extensive in their horizontal dimensions are often less abundant in three-dimensional preserved deposits. Between deltas, grain size compositions of a specific architectural element type (e.g. mouth bars) are more similar than their corresponding sediment supply compositions. This is due to selective deposition of grain size classes across each architectural element type. This selective deposition causes overrepresentation of the same range of grain sizes, even for systems with different sediment supply compositions. When a particular supply composition does not contain enough of the overrepresented grain size class for a particular architectural element, that element will be under-supplied and constitute a smaller proportion of the overall delta deposits. It is imperative to account for over-representation of grain size classes in particular architectural elements when estimating palaeo-sediment supply, delta architecture and morphology from field data. Even when data availability/accessibility does not allow the inclusion of distal deposits in field studies, process-based simulations can contribute valuable information on sediment sorting patterns in three dimensions. Subject Grain sizemouth barriver delta architecturesorting To reference this document use: http://resolver.tudelft.nl/uuid:6a1a0967-e2f8-4d74-92cb-bddcc066d892 DOI https://doi.org/10.1002/dep2.85 ISSN 2055-4877 Source The Depositional Record, 6 (1), 217-235 Part of collection Institutional Repository Document type journal article Rights © 2020 H. van der Vegt, J.E.A. Storms, Dirk Jan R. Walstra, Kjetil Nordahl, Nick C. Howes, A.W. Martinius Files PDF dep2.85.pdf 2.27 MB Close viewer /islandora/object/uuid:6a1a0967-e2f8-4d74-92cb-bddcc066d892/datastream/OBJ/view