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Alleghanian development of the Goat Rock fault zone, southernmost Appalachians: Temporal compatibility with the master decollement

Journal Article · · Geology; (United States)
 [1];  [2];  [3];  [4]
  1. Auburn Univ., AL (United States)
  2. Univ. of North Carolina, Chapel Hill (United States)
  3. Columbus College, GA (United States)
  4. Geological Survey, Reston, VA (United States)
The Goat Rock and associated Bartletts Ferry fault zones, which mark the eastern margin of the Pine Mountain Grenville basement massif, are controversial due to the suggestion that they are rare exposed segments of the late Paleozoic southern Appalachian master decollement. The controversy in part stems from reported middle Paleozoic (Acadian) radiometric dates postulated as the time of movement along these fault zones. Ultramylonite samples from the type area at Goat Rock Dam yield a 287 [plus minus] 15 Ma Rb-Sr isochron interpreted as the time of Sr isotopic rehomgenization during mylonitization. This date is corroborated by Late Pennsylvanian-Early Permian [sup 40]Ar/[sup 39]Ar mineral ages on hornblende (297-288 Ma) and muscovite (285-278 Ma) from neomineralized and dynamically recrystallized rocks within and straddling the fault zone. These Late Pennsylvanian-Early Permian dates indicate the time of right-slip movement (Alleghenian) along the Goat Rock fault zone, which is compatible with the timing suggested by COCORP for thrusting along the southern Appalachian master decollement.
OSTI ID:
6937700
Journal Information:
Geology; (United States), Journal Name: Geology; (United States) Vol. 20:9; ISSN 0091-7613; ISSN GLGYBA
Country of Publication:
United States
Language:
English