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Structural Analysis of Catawissa Quadrangle, Columbia County, Pennsylvania
Full text linkCatawissa Mountain within Columbia County, Pennsylvania is a part of a much large system of mountains called the Appalachian Mountains. Though little more than hills today, the Appalachian Mountains are some of the oldest mountains in the Americas, dating back to after the separation of the supercontinent, Pangea. This presentation is about the structure interpretations of the Catawissa 7.5 Minute Quadrangle, located in Columbia County, Pennsylvania, including fold analysis of the SW trending Catawissa Syncline, formed from Appalachian fold-thrust belt. These analyses are to decipher how the mountain formed from the surrounding regional tectonics and the timeframe of when the folding occurred.
The main rock types in the formations include sandstone, shale, limestone, and a small amount of chert and conglomerates. The main feature of the landscape is a large syncline with parasitic folds in the landscape, which occurred after the Pennsylvanian period. The Catawissa Syncline has an axial plane of 075, 66S, a hinge line of 03, 076, and an interlimb angle of 179, making it gently inclined and a gentle fold. The syncline’s axial plane is near perpendicular to fold-thrust belt forces, which would place the fold being formed between 470 to 240 million years ago by the Alleghanian orogeny in the Permian (Sak et al, 2012)
Groundwater Age of the West Plains, Spokane County, Washington
No full textRadiocarbon dating of groundwater in the West Plains has focused on the basaltic aquifers, since these are the most commonly used for drinking water wells. These aquifers include the Grande Ronde and Wanapum flood basalts from the Columbia RIver Basalt Group (Miocene). However, looking at the West Plains holistically, there is a need for recharge for these, which may include water in basement rocks (Eocene to Cretaceous granite and Cambrian to Mesoproterozoic metasedimentary rocks). Additionally residents in the area have wells within the basement rock aquifers that tend to dry up during years with low precipitation. Groundwater interactions between basement and basaltic aquifers are examined using groundwater age, groundwater models, groundwater budgets and a meteoric water line
