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The Cenozoic structural evolution of a fold-and-thrust belt, northeastern Brooks Range, Alaska

Journal Article · · Geological Society of America, Bulletin; (United States)
 [1]
  1. Univ. of Alaska, Fairbanks (United States)
A Cenozoic fold-and-thrust belt in the eastern structural province of the northeastern Brooks Range exposes polydeformed low-grade metasedimentary and metavolcanic rocks of the pre-Mississippian basement and its sedimentary cover immediately adjacent to much younger foredeep deposits. Analysis of mesoscopic and map-scale structures in the range-front region suggests that at least one pre-Mississippian deformational event was recorded into the basement sequence by north-vergent fold-and-thrust structures and associated penetrative structures. Most of later Cenozoic shortening of the pre-Mississippian rocks was accommodated by thrust duplication, with little development of penetrative mesoscopic structures. Although separated from the underlying basement rocks by a major regional decollement horizon, Cenozoic deformation in the overlying Mississippian through Lower Cretaceous cover sequence also was primarily by thrust duplication. Although local and regional structural trends within the cover sequence suggest that Cenozoic deformation was north-northwest directed, east-west Cenozoic structural trends within the pre-Mississippian rocks may reflect an inherited pre-Mississippian structural grain and/or pre-Mississippian-age structures reactivated during Cenozoic deformation. A regional balanced cross section of the eastern structural province was constructed. 29 refs., 14 figs.
OSTI ID:
5587581
Journal Information:
Geological Society of America, Bulletin; (United States), Journal Name: Geological Society of America, Bulletin; (United States) Vol. 105:3; ISSN 0016-7606; ISSN BUGMAF
Country of Publication:
United States
Language:
English