Gm |
Massive or stratified conglomerates and sandy conglomerates, clast supported or with medium- to coarse-grained sandstone matrix; intraformational clasts of mudstone (up to 25 cm in size); 0.2 to 1.5 m thick beds. Normal gradation and erosional base surface. |
Bedload deposition as diffuse gravel sheets (Hein & Walker 1977Hein F.J., & Walker R.G. 1977. Bar evolution and development of stratification in thegravelly, braided, Kicking Horse River, British Columbia. Canadian Journal ofEarth Science, 14(4):562-570.) or lags deposits by high-magnitude flood flows (Miall 1977Miall A.D. 1977. A review of the braided-river depositional environment. Earth-Science Reviews, 13(1):1-62., Nemec & Postma 1993Nemec W., & Postma G. 1993. Quaternary alluvial fans in southwestern Crete: Sedimentation processes and geomorphic evolution. In: Marzo M., & Puigdefrabegas C. (eds.) Alluvial Sedimentation, International Association of Sedimentologists, Special Publication, 17, Oxford, Blackwell Scientific Publications, p. 235-276.). |
Gt |
Sandy conglomerate, clast supported, granule to pebble quartz clasts; trough cross-stratified sets, 10 to 20 cm thick; normal gradation and erosional base surface. |
3-D gravel dunes (Rust 1978Rust B.R. 1978. A classification of alluvial channel systems. In: Miall A.D. (ed.)Fluvial Sedimentology. Canadian Society Petroleum Geologists Memoir, 5, Calgary, p. 187-198., Todd1996Todd S.P. (1996). Process deduction from fluvial sedimentary structures. In: Carling P.A., & Dawson M.R. (eds.)Advances in Fluvial Dynamics and Stratigraphy. John Wiley, Chichester, p.299-350.). |
Sh |
Medium- to coarse-grained sandstone, moderated- to poorly-sorted; horizontal lamination, granules and pebbles quartz clasts dispersed, at the base of sets or along lamination. 30 cm to 4 m thick bed; rare burrows on top and normal gradation, common fluidizations and erosional base surface. |
Planar-bedded deposits originated via upper flow regime (Miall 1977Miall A.D. 1977. A review of the braided-river depositional environment. Earth-Science Reviews, 13(1):1-62., Best & Bridge 1992Best J., & Bridge J.1992. The morphology and dynamics of low amplitude bedwaves upon stage plane beds and the preservation of planar laminae. Sedimentology, 39(5):737-752.) later modified by bioturbation (Allen 1963Allen J.R.L. 1963. The classification of cross-stratified units.With notes on their origin. Sedimentology, 2(2):93-114.). |
Sl |
Medium- to coarse-grained sandstone, poorly-sorted; low angle cross-lamination. Common intraformational mudstones clasts (up to 7 cm in size) and quartz clasts. |
Washed-out dunes and humbpack dunes (transition between subcritical and supercritical flows) (Harms et al. 1982Harms J.C., Southard J.B., Spearing D.R., Walker R.G. 1982. Structures and sequences in Clastic Rocks. SEPM Short Course9, 161p., Bridge & Best 1988Bridge J.S., & Best J.L. 1988. Flow, sediment transport and bed form dynamics over the transition from dunes to upper-stage plane beds: Implications for the formation of planar laminae. Sedimentology, 35(5):753-763.). |
Ssg |
Medium-grained sandstone; moderately-sorted; sigmoidal cross-bedding; 20 cm to 1.2, thick sets. |
Lower- to upper-flow regime transitional bedform (Wizevich 1992Wizevich M.C. 1992. Sedimentology of Pennsylvanian quartzose sandstones of the Lee Formation, central Appalachian Basin: Fluvial interpretation based on lateral profile analysis. Sedimentary Geology, 78(1-2):1-47.). |
St |
Medium- to very coarse-grained sandstone, badly-sorted, granule and pebble quartz clasts, dispersed or at the base of sets; trough cross-stratification; 10 cm to 3.7 m thick sets; common intraformational mudstones clasts (up to 20 cm in size); normal gradation. |
3-D subaqueous sandy dunes (lower flow regime) (Miall 1996Miall A.D. 1996. The Geology of Fluvial Deposits: Sedimentary Facies, Basin Analysis and Petroleum Geology. New York, Springer-Verlag, 582 p.,Todd 1996Todd S.P. (1996). Process deduction from fluvial sedimentary structures. In: Carling P.A., & Dawson M.R. (eds.)Advances in Fluvial Dynamics and Stratigraphy. John Wiley, Chichester, p.299-350.). |
Sp |
Medium- to coarse-grained sandstone, poorly-sorted; planar cross-stratification. Dispersed granule and pebble clasts, well-rounded and subangular grains. 20 cm to 1.5 m thick sets; normal gradation. |
2-D subaqueous sandy dunes (lower flow regime) (Miall 1996Miall A.D. 1996. The Geology of Fluvial Deposits: Sedimentary Facies, Basin Analysis and Petroleum Geology. New York, Springer-Verlag, 582 p.) and folded because of fluid escape simultaneous with the flow (Todd 1996Todd S.P. (1996). Process deduction from fluvial sedimentary structures. In: Carling P.A., & Dawson M.R. (eds.)Advances in Fluvial Dynamics and Stratigraphy. John Wiley, Chichester, p.299-350.). |
Sr |
Very fine- to medium-grained sandstone; well-sorted; ripple cross-lamination, supercritical and rare subcritical climbing angle. 1 to 10 cm thick sets. |
2D- or 3D-ripples (lower flow regime) with variation of traction/suspension ratio (Allen 1963Allen J.R.L. 1963. The classification of cross-stratified units.With notes on their origin. Sedimentology, 2(2):93-114., Miall 1977Miall A.D. 1977. A review of the braided-river depositional environment. Earth-Science Reviews, 13(1):1-62.). |
Sm |
Fine-grained to conglomeratic sandstone; massive. 20 cm to 2.7 m thick beds; granules quartz clasts and intraformational mudstones clasts dispersed or at the base. |
Rapid deposition of hyperconcentrated flows, fluidization or intensive bioturbation (Miall 1978Miall A.D. 1978. Lithofacies types and vertical profile models in braided rivers deposits: a summary. In: Miall A.D. (ed.). Fluvial Sedimentology,Canadian Society of Petrology and Geology, Memoir, 5, p. 597-604., 1996Miall A.D. 1996. The Geology of Fluvial Deposits: Sedimentary Facies, Basin Analysis and Petroleum Geology. New York, Springer-Verlag, 582 p.). |
Fm |
Red mudstones and siltstones; massive; granular to blocky peds, root traces. 80 cm to 6.4 m thick beds |
Suspension settling from weak currents or standing water; lack of lamination due to (i) flocculation of clay suspension or (ii) loss of lamination associated intensive bioturbation; post-depositional redness under oxidant conditions (Miall 1977Miall A.D. 1977. A review of the braided-river depositional environment. Earth-Science Reviews, 13(1):1-62., Foix et al. 2013Foix N., Paredes J.M., Giacosa R.E. 2013. Fluvial architecture variations linked to changes in accommodation space: Río Chico Formation (Late Paleocene), Golfo San Jorge basin, Argentina. Sedimentary Geology, 294:342-355.). |
Fl |
Mudstones and siltstones gray and greenish gray; thin parallel lamination; with bivalve fossils; 20 cm to 8 m thick beds. |
Suspension settling dominantly from standing water; post-depositional graying under reducing conditions, post-depositional greenish under reducing conditions (Turner 1980Turner P. 1980. Continental Red Beds. Developments in Sedimentology. Amsterdam, Elsevier, 562p., Jo & Chough 2001Jo H.R., & Chough S.K. 2001. Architectural analysis of fluvial sequences in the northwestern part of Kyongsang Basin (Early Cretaceous), SE Korea. Sedimentary Geology, 144(3-4):307-334.). |
P |
Mudstone and muddy sandstone, white to gray; massive or with incipient lamination. |
Subaerial exposition of sediments and obliteration of primary structures (Todd 1996Todd S.P. (1996). Process deduction from fluvial sedimentary structures. In: Carling P.A., & Dawson M.R. (eds.)Advances in Fluvial Dynamics and Stratigraphy. John Wiley, Chichester, p.299-350.) |