Early Permian silt-bed fluvial sedimentation in the Orogrande basin of the Ancestral Rocky Mountains, New Mexico, USA

Greg H. Mack, Mike Leeder, Marta Perez-Arlucea, Brendan D. J. Bailey

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The Lower Permian (Wolfcampian) Abo Formation of south-central New Mexico was deposited by a silt-dominated fluvial system along the western half of the Orogrande basin a few degrees north of the equator in western Pangaea. Fluvial channel deposits consist primarily of: (1) inclined siltstone stratasets up to 4.5 m thick and 25 m wide interpreted as point bar deposits, and (2) symmetrically infilled siltstone stratasets up to 2.4 m thick and 14 m long that may represent avulsion crevasse channels. Both types of channels are dominated by climbing ripple cross-laminae and plane bed laminae, but trough cross-beds are also present, as are several types of soft-sediment deformation structures and desiccation cracks. Red silty mudstones interpreted as floodplain deposits comprise up to 70% of the formation and are interbedded with thin (
Original languageEnglish
Pages (from-to)159-178
Number of pages20
JournalSedimentary Geology
Issue number1-3
Publication statusPublished - 2003

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