Ichnology of fine-grained mixed carbonate-siliciclastic turbidites, Wood River Formation, Pennsylvanian-Permian south-central Idaho

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Palaois; (United States)

DOI:https://doi.org/10.2307/3514909· OSTI ID:6140488

Burton, B R ^[1]; Link, P K ^[2]

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1. Norcen Energy Resources Ltd., Calgary, Alberta (Canada)
2. Idaho State Univ., Pocatello (United States)

In south-central Idaho, the Wood River Formation (Pennsylvanian-Permian) contains a stratigraphic megacycle over 2,000 m thick that is composed of fine-grained mixed carbonate-siliciclastic turbidites. Complete and partial (Bouma) turbidite structural sequences in these rocks are arranged in upward thinning cycles 15 to 30 m thick in which top-cut-out (Ta-c) turbidite facies in the lower part grade vertically into base-cut-out (Td-f) turbidites in the upper part. These cycles are interpreted to represent the autocyclic lateral migration of turbidite lobes. A mixed trace fossil assemblage of pascichnia and fordinichnia are present in these rocks and can be separated into pre-depositional and post-turbidite ichnocoenoses. Quiet-water, pre-turbidite deposits are dark-colored, laminated, and carbonaceous, and represent anoxic to dysoxic inter-turbidite basinal conditions; they contain only Chondrites traces. Turbidity currents introduced oxygenated bottom water which fostered the temporary development of a post-turbidite ichnocoenose of pascichnia which is best developed in the medial portion of turbidite beds and lobes. Trace fossil tiering shows that a post-turbidite ichnocoenose of fodinichnia also developed, and persisted after the disappearance of pascichnia. Animals that produced the fodinichnial traces probably were part of an autochthonous benthic fauna rather than a short-lived allochthonous fauna. They may have migrated with the slowly avulsing turbidite lobes and exploited allochthonous oxygen and the carbonaceous food supply.

• OSTI ID: 6140488
• Journal Information: Palaois; (United States), Journal Name: Palaois; (United States) Vol. 6:3; ISSN PALAE
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CARBONATE ROCKS
CARBONIFEROUS PERIOD
DEVELOPED COUNTRIES
DIMENSIONS
FEDERAL REGION X
FOSSILS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
IDAHO
NORTH AMERICA
PALEONTOLOGY
PALEOZOIC ERA
PERMIAN PERIOD
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STRATIGRAPHY
THICKNESS
USA