Helderberg Group
The Helderberg Group is a geologic group that outcrops in the State New York, Pennsylvania, Maryland New Jersey and West Virginia. It also is present subsurface in Ohio and the Canadian Providence of Ontario It preserves fossils dating back to the Early Devonian and Late Silurian period. The name was coined by T.A Conrad, 1839 in the New York State Geological Survey Annual Report. Named for the Helderberg Escarpment or Helderberg Mountains.[1]
| Helderberg Group | |
|---|---|
| Stratigraphic range: Silurian-Early Devonian | |
| Type | Group |
| Sub-units | Shriver Chert, Becraft Formation, New Scotland Formation, Licking Creek Limestone, Kalkberg Formantion, New Creek or Corriganville Limestone, Coeymans Limestone. Upper Keyser Limestone, Bass Islands, Lower Keyser Limestone, Manlius Limestone |
| Underlies | Onondaga Limestone and Oriskany Formation |
| Overlies | Salina Group, Tonoloway |
| Location | |
| Region | New York Pennsylvania, West Virginia, Maryland and Ohio |
| Country | United States |
| Type section | |
| Named for | Helderberg Escarpment |
| Named by | Conrad, T.A. 1839 |
The Upper portion of the Helderberg, or the Kalkberg Formation is host to the Bald Hill ash bed, dated to 417.6 million years ago.[2]
The Helderberg is composed chiefly of Limestone and Dolomite.[3]
References
- Berdan, Jean. "The Helderberg Group and the Position of the Silurian-Devonian Boundary in North America" (PDF). United States Geological Survey.
- Ver Straeten, Charles; Ebert, James R.; Bartholomew, Alex; Benedict, Lucas; Matteson, Lucas; Shaw, George. "DEVONIAN STRATIGRAPHY AND K-BENTONITES IN THE CHERRY VALLEY – SCHOHARIE VALLEY REGION". Research Gate.
- Demicco, Robet V.; Smith, Jason. "COMPARATIVE SEDIMENTOLOGY OF THE HELDERBERG GROUP IN CENTRAL NEW YORK" (PDF). New York State Geological Association.
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