Sedimentation of the Late Triassic Higham Grit in a south Saskatchewan/Platte River-type braided stream complex, southeastern Idaho and western Wyoming

Journal Article · Thu Jan 01 00:00:00 EST 1987 · Mt. Geol.; (United States)

OSTI ID:5516244

Schmitt, J G; Hazen, D R

The Late Triassic Higham Grit in southeastern Idaho and western Wyoming is comprised predominantly of coarse to medium-grained sandstone and pebble conglomerate with minor mudstone. Lithofacies present include: massive to crudely horizontally bedded pebbly conglomerate (Gm), trough crossbedded sandstone (St), planar crossbedded sandstone (Sp), horizontally stratified sandstone (Sh), ripple crosslaminated sandstone (Sr), and finely laminated sandstone and mudstone (Fl). Deposition occurred in a South Saskatchewan/Platte River-type braided fluvial complex with the development of longitudinal bars and gravel lags (Gm), straight-crested transverse bars (Sp), and sinuous-crested transverse bars and dunes (St). Periodic, high-velocity flow resulted in development of upper flow regime plane beds (Sh). Minor episodes of flood plain inundation produced overbank deposits (Fl). Application of the South Saskatchewan and Platte River braided stream models to the Higham Grit is in good agreement with provenance studies (Schmitt and Hazen, in preparation) which postulate a sediment source area in the Ancestral Rocky Mountains uplift, a distance of 500-700 km to the southeast. Sediment transport distances in both the South Saskatchewan and Platte braided fluvial systems closely approximate this distance.

• Research Organization: Montana State Univ., Bozeman
• OSTI ID: 5516244
• Journal Information: Mt. Geol.; (United States), Vol. 24:1
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC DEPOSITS
DEPOSITION
IDAHO
WYOMING
CONGLOMERATES
FLOODS
GEOLOGIC HISTORY
GEOLOGIC MODELS
RIVERS
ROCKY MOUNTAINS
SANDSTONES
SEDIMENTATION
SEDIMENTS
TRANSPORT
WESTERN US OVERTHRUST BELT
DISASTERS
FEDERAL REGION VIII
FEDERAL REGION X
MOUNTAINS
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
STREAMS
SURFACE WATERS
USA
580100* - Geology & Hydrology- (-1989)