Facies Relationships and Stratigraphic Architecture of Distal, Mixed Tide- and Wave-Influenced Deltaic Deposits: Lower Sego Sandstone, Western Colorado, U.S.A

Abstract

29The facies characteristics and stratigraphic architectures of ancient mixed, wave-and tide-influenced 30 deltas are poorly documented, despite the abundance of analogous modern shorelines. This paper 31 presents the first facies analysis and stratigraphic-architectural characterization of the distal part of 32 the Cretaceous lower Sego Sandstone (Book Cliffs, Colorado, USA), whose correlative proximal part 33 is arguably the most comprehensively documented example of ancient deltaic strata that exhibit 34 evidence for the activity of tides and waves. 36The distal lower Sego Sandstone consists of tide-dominated and wave-dominated deposits arranged 55These facies components and their architectural arrangement suggest that tides and waves operated 56 together throughout deposition of the "lower Sego Delta", but that tide-dominated and wave-57 dominated deposits were spatially partitioned into the proximal and distal parts of each regressive-

Depositional evolution of a progradational to aggradational, mixed-influenced deltaic succession: Jurassic Tofte and Ile formations, southern Halten Terrace, offshore Norway

“…The occurrence of offshore (FA1) and shoreface (FA8) deposits to the south can be explained by three possible scenarios: (1) a change in depositional process from tide-dominated to wave-dominated, due to progradation along the rift-axis, which widened to the south (Fig. 1A) (Legler et al, 2014;Olariu, 2014); (2) wave-dominated deposition was contemporaneous with the tide-dominated deposition along the depositional strike of the shoreline outside of the embayment; and (3) sedimentation could have been locally sourced from a neighbouring horst block or uplifted footwall (Ravnås and Steel, 1998).…”

Oblique closure of the northeastern Paleo-Tethys in central China

“…The entire succession contains bivalve fossils and trace fossils. We interpret these lithofacies as originating from a coastal plain and shallow marine delta [ Legler et al , ]. Here the deposition was differentiated from the lower part of the Jiuligang Formation in a previously published section of the Dangyang Basin (Figure d) [ Liu et al , ].…”

“…The mudstone contains trace fossils, such as Teichichnus and Chondrites , and bivalve fossils, such as Yunnanophorus boulei , Myophoriopis nuculiformis , and Heminajas forulota . We interpret these beds as tidally influenced delta deposits [ Aschoff and Steel , ; Legler et al , ]. Minimum detrital zircon U‐Pb age dates of 216–229 Ma were obtained from the samples from the base of the Mianxian section, which further defined this succession as belonging to the Norian Stage of the Late Triassic (Table S2 in the supporting information and Figure b).…”

Paleoenvironmental Reconstruction of A Late Cretaceous, Muddy, River-Dominated Polar Deltaic System: Schrader Bluff–Prince Creek Formation Transition, Shivugak Bluffs, North Slope of Alaska, U.S.A.

“…They appear well sorted and contain relatively little mud, and rare Sch. These barforms are unlike hummocky cross-stratified and symmetrical-ripple cross-laminated sandbodies more typical of wave-or storm-dominated delta fronts (Hampson and Howell 2005;Bhattacharya 2010) and unlike mud-rich tidal bars found on the fronts of tide-dominated deltas (Willis and Gabel 2001;Legler et al 2014;Dalrymple et al 2012) that typically contain abundant mud drapes, mud rip-up clasts, and evidence of tidal influence (e.g., double mud drapes, herringbone cross-stratification). The fine-grained sandstones in these mouth bars are notably similar in composition and sorting to the very fine-grained sandstones interpreted as terminal distributary channels.…”