Map showing Parks Township Geology
1980 PA Geology Formation Map

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.

Local named geology layers and corresponding ages. Modified from S. N. Perera, A. L. Stigall 2018.

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 Syncline and Anticline lines.
Parks Township, showing syncline and anticline lines.

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.

Generalized Formation Geology of Parks Township
by John A. Harper 2019

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.

Water in Parks Township
Carnahan and Guffy Run can be seen flowing South towards the Kiskiminetas River. Parks Township is represented by the tan shape.

Published Articles about Local Geology Formations

Pennsylvania 310 million years ago

General Geology Report 59
Copyright 1970 Pennsylvania Geological Survey

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.

Parks Township Pennsylvania Mine Subsidence Risks

More Parks Township Geology Information

More Reading About Paleogeography

References

  • 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