Chunky Gal Melange and its tectonic significance

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6455949

Lacazette, A Jr; Rast, N

Detailed mapping of the Chunky Gal Mafic/Ultramafic Complex of SW North Carolina indicates that the complex is involved in a set of ductile shear zones separating pods of less deformed material. The product is a tectonic mixture of fragments of amphibolites, granites, calc-silicates and ultramafic rocks in the Tallulah Falls Fm. Some inclusions are in different states of metamorphism. Foliation within the amphibolite, migmatite and granite lumps is truncated at their edges. The metasediments show a transposed pervasive late foliation (S/sub 2/.) although the sense of intersection of earlier fabrics is locally determinable. Linear fabric elements plunge east. In the amphibolites, the foliation is folded but not transposed. The zone, therefore, is termed the Chunky Gal Melange. Although syntectonic porphyroblasts suggest that the movement began during the metamorphism, the melange postdates the peak of the main regional metamorphism and separates superposed granulite facies rocks from those of amphibolite facies. A weaker lower amphibolite metamorphism postdates the melange. In the vicinity of Chunky Gal Mountain the melange coincides with the premetamorphic Hayesville Thrust of R. Hatcher. A tectonic model suggested here is that the eastern Blue Ridge represents a poorly to fully developed accretionary prism that was built above an east dipping subduction zone during the closure of a marginal sea. Mafic and ultramafic rocks were incorporated with the metasediments at this time. The Hayesville Thrust itself reflects an early stage of suturing of this terrane with North America.

• Research Organization: Pennsylvania State Univ., University Park (USA)
• OSTI ID: 6455949
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
AMPHIBOLITES
CRYSTAL STRUCTURE
DEFORMATION
FEDERAL REGION IV
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOLOGY
GRANITES
IGNEOUS ROCKS
INCLUSIONS
METAMORPHIC ROCKS
METAMORPHISM
MICROSTRUCTURE
NORTH AMERICA
NORTH CAROLINA
PETROGENESIS
PETROLOGY
PLATE TECTONICS
PLUTONIC ROCKS
ROCKS
SUBDUCTION ZONES
TECTONICS
USA