Geology Commons^™

Paleoecological Successions From Shallow-Marine Depositional Environments In Upper Silurian Carbonate Rocks Of Blair County, Pennsylvania, Shadya El-Ashkar

Graduate Theses, Dissertations, and Problem Reports

Studies of paleoenvironment and paleoecology are important for investigating relationships between the different environmental and biological variables that influenced biodiversification patterns during the Silurian Period. The mixed carbonate and siliciclastic rocks of the Bloomsburg and Mifflintown Formations in central Pennsylvania represent transitions between carbonate ramp and deltaic settings. The goal of this study was to assess changes in depositional environment and paleoecology of an undescribed Bloomsburg/Mifflintown locality in Bellwood, Pennsylvania. In central Pennsylvania, the interfingered relationship of mixed carbonate and siliciclastic mudstones of the Mifflintown Formation with red fine-grained sandstones and shales of the Bloomsburg Formation presented challenges for deciphering …

Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson

Graduate Theses, Dissertations, and Problem Reports

The Arctic Alaska–Chukotka microplate is a large Mesozoic–Cenozoic composite terrane that resides at the northern limit of the North American Cordillera. Although its Mesozoic origins are assuredly linked to the opening of the Amerasian Basin of the Arctic Ocean, its Paleozoic origins can be linked to at least three separate paleocontinents, including northern Laurentia, Baltica, and Siberia. Across the Arctic Alaska portion of the microplate, an internal, mid-Paleozoic suture zone presumably separates rocks of the North Slope subterrane (Laurentian affinity) from a collection of smaller subterranes in the southern Brooks Range and Seward Peninsula (Baltic affinity).

The mountains of the …