Abstract

Upper Triassic strata of the nonmarine Chinle Group, the marine/nonmarine Star Peak and Auld Lang Syne Groups (western United States) and the nonmarine Germanic Keuper and marine/nonmarine Alpine Triassic comprise third order sequences that can be divided into systems tracts. Nonmarine sequences of these strata begin with fluvial conglomerate and sandsheets that represent infilling of incised topography, overlain by fluvio-lacustrine clastics (TST), with HSTs of pedoturbated/paludal siltstone and/or sheet sands that display offlap geometry. Marine sequences of these regions contain more heterogeneous facies that define either unconformity bounded, upward deepening cycles, or more discrete transgressive-regressive cycles. The nonmarine and marine sequences of these regions can be correlated by tetrapod and ammonoid biochronologies. These correlations suggest that during the Late Triassic third order global eustatic cycles significantly influenced sedimentation in nonmarine basins far inland from strandline areas.