The Geology of Parks Township includes three named geologic formations inside the boundaries of the township. The majority of the township is located within a geologic group named the Conemaugh. The Conemaugh Group consists of two unique formations. The Glenshaw, which is lower and older. and the Casselman, which is younger and higher. Parks Township rocks are all Pennsylvanian in age, being mostly older than 300 million years of age. I am still performing further research to determine more accurate ages for locales.
My particular dig sites appear to be somewhere between 304 – 306 million years of age. The rocks within Parks Township as a whole appear to be between 303 – 309 million years of age. The marine limestone where a majority of our specimens come from is the Brush Creek Limestone. While elevation can be a good indicator of what rock formations are where, you still need to consider synclines and anticlines locally.
Synclines and Anticlines
The Duquesne-Fairmount Syncline runs through Parks Township starting at Kepple Hill in the South and generally follows north through Guffy Run. The Greensale-Sabinsville Anticline has a termination point in the center of the township boundries.
While you can see a hill or valley over terrain, the formation geology below also rolls independently of what can be seen above the ground. A syncline is a fold that has dropped in elevation while an anticline is a fold that has risen. These broad dips and rises in the formations makes using straight elevation difficult for figuring out formation later locations.
Parks Township Formation Geology
There are several articles below that talk about local formations. These formations are groups of rock layers that make up the local bedrock. There are several correlations you can find with layers over great distances. The Ames Limestone as shown on the map below can also be found all the way over in the state of Ohio. It is made up of the same material and is there due to the same geologic process, in that case being the Ames Sea.
Water in Parks Township
There are two prominent water runs within the Township. The main run is Carnahan Run, which drains the Northern and Eastern portions of the township and empties out at the Southern border, into the Kiskiminetas River. Guffy Run borders the West.
Published Articles about Local Geology Formations
- Glenshaw Formation
- Ames Limestone
- Casselman Formation
- Allegheny Formation
- Parks Township Geology Formations
Pennsylvania 310 million years ago
Mine Subsidence Risks
Since the Allegheny Formation sits at the base in Parks, the Upper Freeport Coal seam is readily mine-able from the exposed hillsides. The 1800’s, particularly after the Civil War, and early 1900’s saw heavy local mining activity to extract this valuable resource. Most if not all local mining has ceased operation in the present day. The map below shows risks of coal mine subsidence within the township.
More Parks Township Geology Information
- Penn State University Libraries Digital Collections – Generalized geologic map of Armstrong County and locations of selected wells (1974)
More Reading About Paleogeography
- Paleomap Paleoatlas – EarthByte Group
- 250 Ma until present, tectonic reconstruction – EarthByte on YouTube
- Ancient Earth Globe – Dinosaur Database
- T.M. Berg, M.K. McInerney, J.H. Way, D.B. MacLachlan (1983) – Stratigraphic Correlation Chart of Pennsylvania
- Wagner, W. R.; Heyman, L.; Gray, R. E.; Belz, D. J.; Lund, R.; Cate, A. S.; and Edgerton, C. D. (1970) – Geology of the Pittsburgh Area, General Geology Report G 59, Pennsylvania Geological Survey, Fourth Series, Harrisburg, PA, 1970
- Perera, S. N.; Stigall, A.L. (2018) – Identifying hierarchical spatial patterns within paleocommunities: An example from the Upper Pennsylvanian Ames Limestone of the Appalachian Basin
- Mine Subsidence Insurance – PA DEP
- Mine Subsidence Risk Map – PA DEP