ABSTRACT With waterfalls and the deepest gorge in Pennsylvania, Ohiopyle State Park provides opportunities to observe a variety of habitats and three-dimensional (3-D) exposures of the Pennsylvanian sandstone most responsible for shaping Laurel Highlands landscapes. Evidence for the relationship between bedrock, ancient climates, and the landscape can be observed at some of the most scenic natural features of the park: Baughman Rock Overlook, Cucumber Falls, Ohiopyle Falls, Meadow Run Waterslide and Cascades, and Youghiogheny River Entrance Rapid. Channel azimuths and lateral variations in thickness of upper Pottsville fluvial/deltaic sandstone suggest that deposition was influenced by deformation of this part of the Allegheny Plateau during the Alleghanian orogeny. Geologic features of Pottsville sandstone outcrops include a 10-m- (~33-ft-) long Lepidodendron fossil and a 3-D exposure of a meter-high Pennsylvanian subaqueous sand dune and scour pit. Cosmogenic age dating has indicated very slow erosion of hard sandstone in an upland location at Turtlehead Rock and informed estimation of Pleistocene/Holocene waterfall retreat rates of Ohiopyle and Cucumber Falls. Bedrock exposures supporting scour habitats along the Youghiogheny River occur only in a limited area of Youghiogheny Gorge where knickpoint migration and bedrock erosion were relatively recent. Geologic factors, including locations of major tributaries, development of bars that constrict river flow, and proximity of Homewood sandstone outcrops as sources of boulder obstacles in the river, contributed to the class, location, and nature of whitewater rapids in the lower Youghiogheny River.

Abstract Western Pennsylvania is rich in oil history, and many of the fledgling petroleum industry’s “firsts” happened right here between the late nineteenth and early tentieth centuries. First and foremost, it is home to the Drake well, the first-ever economic well intentionally drilled to produce oil. In addition, western Pennsylvania has bragging rights to various industry advancements, from the way geologic samples were collected and interpreted, to how wells were drilled and stimulated for production, to early oil refining techniques, marketing, and production. In this field guide, we discuss the petroleum geology and history of estern Pennsylvania in general and three important oil-producing sites in particular: (1) the McClintock #1 well, Rouseville; (2) the Drake well, Titusville; and (3) Muddy Creek oil field, Prospect. Each of these sites produced oil from Upper Devonian reservoirs and spurred additional petroleum exploration and development in the central Appalachian basin.

Abstract Western Pennsylvania is rich in oil history, and many of the fledgling petroleum industry’s “firsts” happened right here between the late nineteenth and early tentieth centuries. First and foremost, it is home to the Drake well, the first-ever economic well intentionally drilled to produce oil. In addition, western Pennsylvania has bragging rights to various industry advancements, from the way geologic samples were collected and interpreted, to how wells were drilled and stimulated for production, to early oil refining techniques, marketing, and production. In this field guide, we discuss the petroleum geology and history of estern Pennsylvania in general and three important oil-producing sites in particular: (1) the McClintock #1 well, Rouseville; (2) the Drake well, Titusville; and (3) Muddy Creek oil field, Prospect. Each of these sites produced oil from Upper Devonian reservoirs and spurred additional petroleum exploration and development in the central Appalachian basin.

Abstract The latest Devonian (Famennian) is characterized by an extensive Southern Hemisphere glaciation. Deposits resulting from this glaciation are present in several formations in the mid-Atlantic region, including the Hampshire, Catskill, Rockwell, and Spechty Kopf. The Hampshire (= Catskill) Formation exhibits a noticeable stratigraphic change upsection from the middle to the top. The middle part consists of thick intervals of red, channel-phase sandstones with thin overbank siltstone and mudstone. These mudstones contain poorly developed, calcareous paleosols. The top of the Hampshire Formation consists of greenish-gray sandstones containing abundant coaly plant fragments, coalified logs, and pyrite, interbedded with thick paleo-Vertisols. The upsection increase in preserved terrestrial organic matter suggests the onset of environmental conditions that became increasingly wet. The Late Devonian escalation in climate wetness culminated in the development of a stratigraphically and spatially restricted succession of diamictite-mudstone-sandstone interpreted as having formed in glacial and proglacial environments. These glacial environments are recorded in the lower Rockwell Formation of western Maryland and contemporaneously deposited intervals of the Spechty Kopf Formation of northeastern Pennsylvania. Sheared and massive diamictite facies are interpreted as lodgement and meltout deposits, respectively; whereas, bedded diamictites are interpreted as resedimented deposits. The diamictite facies is locally overlain by a mudstone facies with variable characteristics. Both the massive and deformed mudstone lithofacies are interpreted as a clast-poor, subaqueous glaciolacustrine deposit. Laminated mudstones are interpreted as forming in quiet glaciolacustrine environments. The pebbly sandstone facies is interpreted as proglacial braided outwash deposits that both preceded glacial advance and followed glacial retreat.