Initiation and early evolution of a forearc basin: Georgia Basin, Canada

摘要: Abstract The lower Nanaimo Group was deposited in the (forearc) Georgia Basin, Canada and records basin's initiation early depositional evolution. strata are subdivided into 11 lithostratigraphic units, which identified based on lithology, paleontology, texture position relative to both basal nonconformity each other. Significant topography nonconformity, however, has resulted assignment of units that not time correlative, hence, cannot reliably be used accurately reconstruct basin Herein, we present a sequence stratigraphic framework for Comox Sub‐Basin (northern Basin) integrates facies analysis maximum ages (MDAs) derived from detrital zircon. This is define significant sub‐basin‐wide surfaces bound record evolution during its stages development. Seven distinct phases 700 m Group. Depositional separated by marine flooding surfaces, regressive or disconformities. overall stratigraphy reflects net transgression manifested as an upwards transition braided fluvial conglomerates mudstones. Transgression interrupted periods shoreline progradation, MDAs reveal disconformity lowermost part Sub‐Basin. Stratigraphic reconstruction reveals two dominant depocenters (along strike) coarse clastics (sandstones conglomerates) development Basin. these attributed subduction/tectonism driving subsidence north‐northwest uplift central Our work confirms earliest development, Basin evolved underfilled, ridged forearc experienced slow stepwise drowning shoal‐water rapid subsidence. We also propose reasonable analogue basins globally, many forearcs similar histories their