CHRONOLOGY OF MAJOR METAMORPHIC EVENTS IN THE SOUTHEASTERN UNITED STATES
Journal Article
·
· American Journal of Science (U.S.)
Potassium-argon and rubidium-strontium age measurements have been made on a variety of granites, pegmatites, gneiases and schists which comprise the plutonicmetamorphic complex of the Piedmont and Blue Ridge of the southeastern United States. Large portions of the area appear to have been metamorphosed initially approximately at the same time as the Grenville Province, i.e., about 900 to 1100 m.y. ago. Superimposed on this older metamorphic province was a major orogenic event culminating at about 350 m.y. with widespread recrystallization of existing rocks and intrusion of pegmatites in the Spruce Pine, Franklin-Sylva and Bryson City Districts, and granites in the Virginia and North Carolina Piedmont. There is strong evidence of an additional metamorphic epoch between 350 and 1000 m.y., but its effects have been largely obliterated by the 350 m.y. event. In western North Carolina a transition of apparent ages from 355 to 890 m.y. occurs in the same rock unit. (Cranberry gneiss) over a distance of about 10 miles across the strike of the border- of the 350 m.y. event. In the southeastern Piedmont of Georgia and South Carolina a younger metamorphic event or events can be detected producing rocks of apparent age ranging from 230 to 310 m.y. The time of these orogenies is compared with those in the Central and Northern Appalachians. Evidence is accumulating that the Holmes' time scale will have to be considerably lengthened. (auth)
- Research Organization:
- Columbia Univ., Palisades, N.Y.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-013923
- OSTI ID:
- 4141985
- Journal Information:
- American Journal of Science (U.S.), Journal Name: American Journal of Science (U.S.) Vol. Vol: 257; ISSN AJSCA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Rubidium-strontium age determinations of muscovites and biotites from pegmatites of the Blue Ridge and Piedmont
Review of potential host rocks for radioactive waste disposal in the southeast United States-Southern Piedmont subregion
Uranium-lead method of age determination. Part II. North American localities
Journal Article
·
Tue May 01 00:00:00 EDT 1962
· Journal of Geophysical Research
·
OSTI ID:4830317
Review of potential host rocks for radioactive waste disposal in the southeast United States-Southern Piedmont subregion
Technical Report
·
Wed Oct 01 00:00:00 EDT 1980
·
OSTI ID:6682267
Uranium-lead method of age determination. Part II. North American localities
Journal Article
·
Mon Dec 31 23:00:00 EST 1956
· Geological Society of America, Bulletin
·
OSTI ID:4793264