The Towaliga-Goat Rock and Bartletts Ferry deformation zones are major tectonic boundaries of the southeastern Piedmont. The Towaliga zone separates the Pine Mountain Belt and the Inner Piedmont and the Goat Rock and Bartletts Ferry Zones separate the Pine Mountain and Uchee Belt. / The Uchee Belt is composed of granitic gneisses and amphibolites modified by at least five deformational phases, each represented by distinctive mesoscopic folding patterns. The earliest (F(,1)) is a poorly developed folding of obscure compositional layering (S(,0)). Later leucocratic banding (S(,1)) is folded by recumbent isoclines with subhorizontal axial plane cleavage (S(,2)). Intensification of S(,2) to the northwest produces the southeast dipping mylonitic foliation of the Goat Rock and Bartletts Ferry Zone. A third phase (F(,3)) produces overturned similar to concentric folds rotated about subhorizontal axes with northwest transport indicated by northwest vergence. Cross folding (F(,4)) is followed by displacement on the fault at the base of the Uchee Belt, which is interpreted as a thrust emplacing Uchee rocks over the south limb of the Pine Mountain antiform. Quartz fabrics are not rotated by F(,3) and are interpreted as syn- or post- F(,3) recrystallization and recovery fabrics. A pre- S(,2) major regional metamorphic event (M(,1)) to at least sillimanite grade is recognized followed by a weak post- F(,4) retrogressive event (M(,2)). / Only the north limb of the Pine Mountain antiform and a portion of the ancient core are exposed in the study area. The Pine Mountain rocks are overprinted by at least five deformational phases. The earliest phase (F(,1)) is characterized by isoclinal folding about subhorizontal axes of the original compositional layering (S(,0)) with southeast transport indicated by southeast vergence. Intensification of the axial plane cleavage (S(,1)) produces the northwest dipping Towaliga mylonitic foliation which is modified by continued isoclinal and assymetrical folding (F(,2)) about subhorizontal axes with southeast vergence. A third phase (F(,3)) involving the adjacent Inner Piedmont, Towaliga Zone and north limb of the Pine Mountain antiform, is characterized by right lateral transport. Isoclinal and monoclinal folding (F(,3)) with axes plunging northwest downdip and axial plane cleavage (S(,3)) coplanar to S(,1) exhibits dextral vergence. Broad folds and undulations (F(,4)) of S(,1) - S(,3) are tentatively correlated with F(,4) of the Uchee Belt. A regional metamorphic event to sillimanite grade (M(,1)) followed by a retrogressive event (M(,2)) is recognized. The Towaliga quartz fabrics are interpreted as syn- or post- F(,3) recrystallization and recovery overprinted by later deformation fabrics, possibly F(,4). / The movement picture outlined by mesoscopic structural patterns poses considerable difficulty for a "meganappe" model. The patterns can be accounted for by regional compressive folding accompanied by ductile drag folding and mylonitization on the limbs of a major anticlinal structure. / Source: Dissertation Abstracts International, Volume: 42-06, Section: B, page: 2272. / Thesis (Ph.D.)--The Florida State University, 1981.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74577 |
| Contributors | HOLLAND, WILLIS ALGEON, JR., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 116 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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