Faculty Mentor
Chad Pritchard
Presentation Type
Poster
Primary Discipline of Presentation
Geosciences
Abstract
The Northwest corner of Virginia, within the Appalachian Mountains, formed during a collision of continents called the Alleghenian Orogeny roughly 250 million years ago(Ma). This event caused tectonic plates to collide, reforming the fractured continental crust back into a new supercontinent, Pangaea. This process took over 100 Ma and closed the Rheic Ocean. These large-scale compressional tectonics had several effects including formation of the Allegheny Plateau and Taconic Mountain range, which has gradually eroded exposing a series of plunging folds and imbricated thrust faults. This poster presents a structural analysis of the Rileyville quadrangle to help decipher regional geologic history and a possible origin for folds in Page County, Virginia.
Rocks mapped in the quadrangle range in age from Ordovician to late Devonian period. Analysis of rock attitude calculated the orientation and style of the main folds, alongside minor anticlines and synclines. The larger syncline structure is moderately inclined with an axial plane dipping 33 degrees NW and striking at 221. The fold axis was virtually horizontal with a plunge of 0.1, trending 041. The second order anticline and syncline pair were very similar orientations, but identified as open, upright, horizontal folds. This feature demonstrates the extensional tectonics that led to the development of a series of thrust faults along the edge of the fold paired with an approximate stress from 130 (SE) during the Alleghenian Orogeny. The unconformities found in the stratigraphy were associated with intervals of little to no deposition and instead indicate periods of erosion.
Recommended Citation
Fergen, Sydney, "Historical Structural Analysis of the Rileyville Quadrangle, Page County, Virginia" (2024). 2024 Symposium. 13.
https://dc.ewu.edu/srcw_2024/works_2024/works_2024/13
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Included in
Historical Structural Analysis of the Rileyville Quadrangle, Page County, Virginia
The Northwest corner of Virginia, within the Appalachian Mountains, formed during a collision of continents called the Alleghenian Orogeny roughly 250 million years ago(Ma). This event caused tectonic plates to collide, reforming the fractured continental crust back into a new supercontinent, Pangaea. This process took over 100 Ma and closed the Rheic Ocean. These large-scale compressional tectonics had several effects including formation of the Allegheny Plateau and Taconic Mountain range, which has gradually eroded exposing a series of plunging folds and imbricated thrust faults. This poster presents a structural analysis of the Rileyville quadrangle to help decipher regional geologic history and a possible origin for folds in Page County, Virginia.
Rocks mapped in the quadrangle range in age from Ordovician to late Devonian period. Analysis of rock attitude calculated the orientation and style of the main folds, alongside minor anticlines and synclines. The larger syncline structure is moderately inclined with an axial plane dipping 33 degrees NW and striking at 221. The fold axis was virtually horizontal with a plunge of 0.1, trending 041. The second order anticline and syncline pair were very similar orientations, but identified as open, upright, horizontal folds. This feature demonstrates the extensional tectonics that led to the development of a series of thrust faults along the edge of the fold paired with an approximate stress from 130 (SE) during the Alleghenian Orogeny. The unconformities found in the stratigraphy were associated with intervals of little to no deposition and instead indicate periods of erosion.
