Structure of an active foreland fold and thrust belt,Papua New Guinea |
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| Authors: | M S Craig K Warvakai ? |
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| Institution: | 1. Department of Earth and Environmental Sciences, 25800 Carlos Bee Boulevard , California State University , East Bay, Hayward, CA, 94542, USA mitchell.craig@csueastbay.edu;3. Department of Geosciences , University of Papua New Guinea , Port Moresby, Papua New Guinea |
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| Abstract: | Geological structure of the active foreland fold and thrust belt of Papua New Guinea has been interpreted using high-quality seismic-reflection data. Three en échelon anticlines, the Strickland, Cecilia and Wai Asi, are located along the frontal margin of the Papuan Fold Belt. All three are foreland-vergent and cut by hinterland-dipping thrust faults that sole into a common detachment beneath the Oligocene to Miocene Darai Limestone. Two of the anticlines are linked by a right-lateral transfer zone. Folding occurs primarily in the upper 2000 m of strata, which consist of Darai Limestone overlain by Miocene to Quaternary siliciclastic sedimentary rocks. Beneath the Darai Limestone lies the less-competent shaly Ieru Formation, which exhibits disharmonic folding and variable bed thickness. Seismic-reflection data clearly show that the Plio-Pleistocene upper Era Beds are deformed to the same extent as the underlying Darai Limestone, demonstrating that most of the observed deformation has occurred during the Late Pliocene and Pleistocene. |
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| Keywords: | compression fold and thrust belt foreland basin Papua New Guinea seismic reflection stratigraphy structure thrust faulting |
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