- Usage in publication:
-
- Hellam conglomerate member*
- Modifications:
-
- Named
- Dominant lithology:
-
- Conglomerate
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Hellam conglomerate member of the Chickies quartzite named and accepted for USGS usage in PA. Is basal member of Chickies quartzite [and is also basal member of the "Hellam" quartzite, a name used by Frazer (1886) for the Chickies. Lesley (1892) says that Chiques sandstone is not only the oldest name for this formation but is the locality of its finest exposure.] Rests unconformably on Precambrian schist or greenstone and aporhyolite. Age is Early Cambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Hellam Member*
- Modifications:
-
- Revised
- Age modified
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Redefined Hellam Member of Chickies Formation. Age changed to latest Precambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Hellam Member*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Hellam Member of the Chickies Quartzite is in lower part of the Chickies. Consists of coarse-grained, gray, tourmaline-bearing quartzite, arkose-pebble conglomerate, and interbeds of black slate and biotite schist. Rests unconformably and abruptly on a wide variety of Proterozoic gneisses. Age is Early Cambrian.
Source: GNU records (USGS DDS-6; Reston GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).