Quasi-planer-laminated sandstone beds of the Lower Cretaceous Bootlegger Member, north-central Montana: Evidence of combined-flow sedimentation

Journal Article · Sat May 01 00:00:00 EDT 1993 · Journal of Sedimentary Petrology; (United States)

OSTI ID:6523222

Arnott, R W.C. ^[1]

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1. Univ. of Ottawa, Ontario (Canada)

Lower-shoreface to shallow-shelf strata of the Bootlegger Member of the Lower Cretaceous Blackleaf Formation are characterized by interbedded sandstone and mudstone. Sandstone beds are characterized by a peculiar planar lamination showing a subtle although perceptible undulation; spacing-to-height ratios of the undulation are generally 100 or more. Typically the undulation shows no evidence of lateral accretion but only vertical aggradation, and as a result most beds consist of a single laminaset. Aspects of quasi-planar-laminated beds indicate single-event storm sedimentation, and paleocurrent data indicate offshore sediment transport. By its sedimentary characteristics and its similarity with a bed configuration generated in an experimental wave duct, quasi-planar lamination is produced by high-energy combined flows. This style of stratification should be common in the shallow-marine stratigraphic record, and its recognition should aid in interpreting high-energy, combined-flow depositional events.

• OSTI ID: 6523222
• Journal Information: Journal of Sedimentary Petrology; (United States), Vol. 63:3; ISSN 0022-4472
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
MONTANA
GEOLOGIC FORMATIONS
SANDSTONES
PETROLOGY
STRATIFICATION
CRETACEOUS PERIOD
DEPOSITION
ENVIRONMENTAL TRANSPORT
FLUID FLOW
GEOLOGIC HISTORY
GEOLOGIC MODELS
SEDIMENTS
STRATIGRAPHY
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGY
MASS TRANSFER
MESOZOIC ERA
NORTH AMERICA
ROCKS
SEDIMENTARY ROCKS
USA
580000* - Geosciences