Cyclic Sedimentation Patterns in the Middle and Upper Ordovician Trenton Group of Central Pennsylvania
Mary Anne Gardiner-Kuserk, 1988. "Cyclic Sedimentation Patterns in the Middle and Upper Ordovician Trenton Group of Central Pennsylvania", The Trenton Group (Upper Ordovician Series) of Eastern North America: Deposition, Diagenesis, and Petroleum, Brain D. Keith
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The carbonate facies of the Middle and Upper Ordovician of Central Pennsylvania show repetitive sequences of micrite, bioclastic limestone and siliciclastic shale. Five repetitive patterns based on sedimentologic and paleontologic data are present. These sequences are a result of storm deposition, as indicated by shell and intraclastic lags, fining upward trends, abrupt contacts between the beds, and the multidirectional sole marks. The series of sequences is a result of the decreasing effects of these storms on the deepening carbonate platform-ramp during the Middle and Late Ordovician.
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The Trenton Group (Upper Ordovician Series) of Eastern North America: Deposition, Diagenesis, and Petroleum
Regional facies for the Upper Ordovician Series (global classification) of eastern North America consist of clean (pure) carbonates, mixed carbonates and terrigenous clastics, shale, terrigenous clastics coarser than shale, and terrigenous clastics prograding over carbonates. The last facies is characteristic of the Upper Ordovician. Maps and cross sections for stages of the Upper Ordovician demonstrate the influence of regional tectonic events on the sedimentation pattern of these facies.