Helderberg Group (geology)

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.

Helderberg Group
Stratigraphic range: Lochkovian-Emsian
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TypeGroup
Sub-units
Port Ewen Shale
Minisink Limestone
New Scotland Formation
Maskenozha Member
Flatbrookville Member
Coeymans Formation
Kalkberg / Stormsville Members
Shawnee / Revanna Members
Depue Limestone Member
Peters Valley Member
Manlius Limestone
Thacher Member
Underlies
Onondaga Limestone
Oriskany Formation
Overlies
  • Salina Group
  • Tonoloway
Lithology
PrimaryLimestone
OtherDolomite, Chert
Location
Region
  •  New York (state)
  •  Pennsylvania
  •  West Virginia
  •  Maryland
  •  Ohio
CountryUnited States
Type section
Named forHelderberg Escarpment
Named byConrad, 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.

The Helderberg is composed chiefly of limestone and dolomite.

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