Landforms in Carbonate Areas
Karst topography is a landscape form created by the dissolution of layers of soluble carbonate bedrock such as limestone or dolomite and results in unusual subsurface drainage. Many carbonate areas in PA display one or more of the following distinctive surface and subsurface features :
Groundwater in karst areas is as easily polluted as surface water. Overloaded or malfunctioning septic systems in these areas may allow sewage to flow directly into underground channels or caverns.
Dissolving limestone produces conditions that can lead to:
extremely high permeability rates
reduced opportunities for contaminants to be treated
As a result of waters bypassing naturally- filtering non-carbonate soil and rock, water supplies in carbonate regions may become unsafe.
Contamination also occurs when sinkholes are used as trash dumps.
Weathering and Erosion of Carbonate
Weathering in a carbonate area may result in a variety of large or small-scale features both on the surface and subsurface. Beneath the surface, complex underground drainage systems and extensive caves and cavern systems may form.
The need for care when dealing with carbonate soils and bedrock is clear. Sinkholes can develop gradually as surface openings enlarge, but often erosion is unseen until the roof of an underground cavern suddenly collapses. Such events have swallowed homes, cars, and even highways, as on PA Rte. 33 in Nazareth in 2004.
Penn's Trail Investigations
Penn’s Trail conducts a combination site inspection and subsurface investigation by a Professional Geologist who will:
correlate published mapping with current surface and subsurface indicators
use remote sensing techniques for parcels located within or adjacent to mapped carbonate bedrock
evaluate sites for indicators of carbonate weathering
provide verification of either the presence or absence of carbonate bedrock
issue a report of methodology
make recommendations for further testing if necessary.
Our investigations are performed to ensure your project will comply with all municipal or state land development requirements.
No method to accurately predict future carbonate feature development has been developed to date. Our work and subsequent reporting cannot guarantee future behavior of the carbonate bedrock or its overburden. Recommendations and opinions are based on information gathered at the time of the site evaluation and are subject to revision as new information becomes available.