ABSTRACT The Fernow Experimental Forest (the “Fernow”) is an 1860-ha (4600-acre) research forested watershed in Parsons, West Virginia, USA. The Fernow has been in operation since 1934 and has historically been the site of timbering and silvicultural research programs. Beginning in the 1950s, a water quality research program was established in the Fernow to assess the effects of different forestry management techniques on water quantity and quality. As a result, most peer-reviewed research from the Fernow has focused on water quality data directly related to forestry efforts with little mention of the effects of geology, hydrogeology, or climate on water resources in the Fernow. Further, the Fernow is representative of Appalachian headwater mountain watersheds and is a protected and secure research site in the greater Monongahela National Forest. This, in combination with the long-term data records from the water research program, make the Fernow an ideal location for further geologic and hydrologic investigations in forested mountain watersheds. The geology of the Fernow is dominated by moderately dipping Paleozoic-aged strata with local karst features (e.g., springs) occurring in one unit. The hydrology of the Fernow consists of intermittent and perennial streams that are reactive to seasonal weather patterns. This field guide serves as an overview of the geology and hydrology of the Fernow and surrounding region to be used as a teaching and recruitment tool to advance the geologic understanding of Allegheny Mountain headwaters.

ABSTRACT This trip explores three different occurrences of a diamictite-bearing unit in the transition between Upper Devonian redbeds of the Hampshire Formation (alluvial and fluvial deposits) and Mississippian sandstones and mudstones of the Price/Pocono Formations (deltaic deposits). Palynology indicates that all the diamictites examined are in the LE and LN miospore biozones, and are therefore of Late Devonian, but not latest Devonian, age. Their occurrence in these biozones indicates correlation with the Cleveland Member of the Ohio Shale, Oswayo Member of the Price Formation, and Finzel tongue of the Rockwell Formation in the central Appalachian Basin and with a large dropstone (the Robinson boulder) in the Cleveland Member of the Ohio Shale in northeastern Kentucky. Although several lines of evidence already support a glaciogenic origin for the diamictites, the coeval occurrence of the dropstone in open-marine strata provides even more convincing evidence of a glacial origin. The diamictites are all coeval and occur as parts of a shallow-marine incursion that ended Hampshire/Catskill alluvial-plain accumulation in most areas; however, at least locally, alluvial redbed accumulation continued after diamictite deposition ended. The diamictites are parts of nearshore, marginal-marine strata that accumulated during the Cleveland-Oswayo-Finzel transgression, which is related to global eustasy and to foreland deformational loading during the late Acadian orogeny. Detrital zircon data from clasts in a diamictite at Stop 3 (Bismarck, West Virginia) indicate likely Inner Piedmont, Ordovician plutonic sources and suggest major Acadian uplift of Inner Piedmont sources during convergence of the exotic Carolina terrane with the New York and Virginia promontories. Hence, the Acadian orogeny not only generated high mountain source areas capable of supporting glaciation in a subtropical setting, but also through deformational foreland loading, abetted regional subsidence and the incursion of shallow seas that allowed mountain glaciers access to the open sea.

Recognition of the timing of peak metamorphism in the eastern Blue Ridge (ca. 460 Ma), Inner Piedmont (ca. 360 Ma), and Carolina terrane (ca. 540 Ma) has been critical in discerning the history of the collage of terranes in the hinterland of the southern Appalachian orogen. The Inner Piedmont consists of two terranes: the Tugaloo terrane, which is an Ordovician plutonic arc intruding thinned Laurentian crust and Iapetus, and the Cat Square paragneiss terrane, which is interpreted here as a Silurian basin that formed as the recently accreted (ca. 455 Ma) Carolina terrane rifted from Laurentia and was transferred to an oceanic plate. The recognition of an internal Salinic basin and associated magmatism in the southern Appalachian hinterland agrees with observations in the New England and Maritime Appalachians. Structural analysis in the Tugaloo terrane requires the Inner Piedmont to be restored to its pre-Carboniferous location, near the New York promontory. At this location, the Catskill and Pocono clastic wedges were deposited in the Devonian and Mississippian, respectively. Between the two wedges, an enigmatic formation (Spechty Kopf and its correlative equivalent Rockwell Formation) was deposited. Polymictic diamictites within this unit contain compositionally immature exotic clasts that may prove to have been derived from the Inner Piedmont. Following deposition of the Spechty Kopf and Rockwell Formations, the Laurentian margin became a right-lateral transform plate boundary. This continental-margin transform was subsequently modified and translated northwest above the Alleghanian Appalachian décollement. Thus, several critical recent observations presented here inspire a new model for the Silurian through Mississippian terrane dispersal and orogeny that defines southern Appalachian terrane geometry prior to emplacement of the Blue Ridge–Inner Piedmont–Carolina–other internal terranes as crystalline thrust sheets.

Abstract The thickest and most laterally continuous upper Carboniferous molasse in the central Appalachians is located in the Southern Anthracite Field of northeastern Pennsylvania. Substantial deposits extend throughout northeastern Pennsylvania where >90% of the total anthracite (original reserves) in the United States and the thickest coal beds of the eastern United States are located. The abundance of and demand for this resource allowed the region to prosper in the nineteenth and twentieth centuries. In Pottsville, Pennsylvania, the exposed Upper Mississippian to Middle Pennsylvanian molasse reveals a progressive evolution from a semiarid alluvial plain to a semihumid alluvial plain to a humid alluvial plain. The anthracite beds occur and thicken with increased humid conditions. The progression is also exposed in Tamaqua, Pennsylvania, where convenient access to the underlying Lower Mississippian strata is available, thus providing a section of all Carboniferous formations in the region. Finally, in Lansford, Pennsylvania, a renovated deep anthracite mine illustrates the historical methods and working conditions that existed to extract the valuable resource and allow the region to flourish and fuel the Industrial Revolution.

Study of slope movements triggered by the storm of November 3–5, 1985, in the central Appalachian Mountains, U.S.A., has helped to define the meteorologic conditions leading to slope movements and the relative importance of land cover, bedrock, surficial geology, and geomorphology in slope movement location. This long-duration rainfall at moderate intensities triggered more than 1,000 slope movements in a 1,040-km 2 study area. Most were shallow slips and slip-flows in thin colluvium and residuum on shale slopes. Locations of these failures were sensitive to land cover and slope aspect but were relatively insensitive to topographic setting. A few shallow slope movements were triggered by the same rainfall on interbedded limestone, shale, and sandstone. Several large debris slide-avalanches were triggered in sandstone regolith high on ridges in areas of the highest measured rainfall. Most of these sites were on slopes that dip 30 to 35° and lie parallel to bedding planes, presumably the sites of least stability.

Rock block slides as large as 20,000,000 m 3 occur in northeastern Pennsylvania where dip-slopes are undercut by rivers or by man. Slippage occurs along bedding in mudstone units where bedding dips out of the slope. The planar bedrock slabs are bounded by joints or the ground surface. The slab’s rectangular, arcuate, or triangular plan-view shape is controlled by joint and outcrop orientation on the slope. A 10 4 variation in slide-block volume is controlled primarily by differences in slope length and block surface area. Some blocks slide off the slope and onto the flood plain, while others only open up fissures and remain on the slope. Blocks move straight downslope or pivot toward an unbounded or more undercut side. The slides are part of an on-going process dating from post-late Wisconsinan glaciation (18,000 yr B.P.) to present. The region is seismically inactive; three historic slides are associated with high moisture conditions, so prehistoric slides were also probably triggered by high cleft-water pressure.