GEOLEX databaseGeologic Unit: Laffingal
Publication: Crawford, T.J., Higgins, M.W., Crawford, R.F., Atkins, R.L., Medlin, J.H., and Stern, T.W., 1999, Revision of stratigraphic nomenclature in the Atlanta, Athens, and Cartersville 30- x 60-minute quadrangles, Georgia: Georgia Geological Survey Bulletin, no. 130, 45 p.Usage in Publication:
Laffingal Member*
| Modifications: | Geologic Province: | Dominant Lithology: |
|---|---|---|
| Named |
Appalachian basin |
Schist Phyllite |
Summary:
Named as a member of Nantahala Formation. Named for crossroads of Laffingal, Allatoona Dam 7.5-min quad, Bartow Co., northwestern GA. Consists of very dark-gray to black, graphitic to very graphitic phyllite/schist locally containing small garnets and commonly containing pyrite cubes. Contains lenses of blue-quartz and microcline granule, pebble, and locally cobble and boulder conglomerate identical to that of undivided Nantahala. Where not highly sheared, is interbedded or interlaminated with thin, fine-grained, iron-rich quartzose beds or laminae like those of Nantahala to the north and northeast. In most outcrops, Laffingal is sheared to button schist or buttony phyllite and quartzose laminae have been mobilized into folded quartz lenses or stringers. Directly overlies Corbin Metagranite in many places in Corbin massif; structurally both underlies and overlies pods of Corbin Metagranite in Mulberry Rock structure; structurally and probably stratigraphically underlies Bill Arp Formation. Age is Late Proterozoic to Middle Ordovician based on same reasoning for age of Nantahala Formation: must be younger than Middle(?) to Late Proterozoic Corbin Metagranite because Nantahala contains detritus from Corbin, and is probably older than Middle Ordovician Rockmart Slate because Nantahala is thrust upon Rockmart. Report includes geologic map and correlation chart.
Source: GNU records (USGS DDS-6; Reston GNULEX).