The Uluguru Mountains of eastern Tanzania represent a key area to unravel the tectonic history of Gondwana assembly along the Neoproterozoic East African Orogen. On the basis of combined structural and 40Ar/39Ar geochronological investigations, we have re-interpreted the structural architecture of the region. Texturally-late, ductile to cataclastic low-angle tectonic contacts are recognised, which delimit the contacts between the main lithological units that form a post-metamorphic, NW-verging nappe stack. 40Ar/39Ar geochronology places this nappe-forming event at about 550 Ma, post-dating tonalitic dyke emplacement at about 580 Ma. Results from this study (i) demonstrate that a distinct and later episode of convergence occurred in the region at about 550 Ma, when previous structural elements of the East African Orogen were finally juxtaposed; and (ii) allow to extend models involving the polyphase assembly of Gondwana to East Africa
Rossetti, F., Cozzupoli, D., Phillips, D. (2008). Compressional reworking of the East African Orogen in the Uluguru Mountains of eastern Tanzania at ~550 Ma: implications for the final assembly of Gondwana. TERRA NOVA, 20, 59-67.
Compressional reworking of the East African Orogen in the Uluguru Mountains of eastern Tanzania at ~550 Ma: implications for the final assembly of Gondwana
ROSSETTI, FEDERICO;COZZUPOLI D;
2008-01-01
Abstract
The Uluguru Mountains of eastern Tanzania represent a key area to unravel the tectonic history of Gondwana assembly along the Neoproterozoic East African Orogen. On the basis of combined structural and 40Ar/39Ar geochronological investigations, we have re-interpreted the structural architecture of the region. Texturally-late, ductile to cataclastic low-angle tectonic contacts are recognised, which delimit the contacts between the main lithological units that form a post-metamorphic, NW-verging nappe stack. 40Ar/39Ar geochronology places this nappe-forming event at about 550 Ma, post-dating tonalitic dyke emplacement at about 580 Ma. Results from this study (i) demonstrate that a distinct and later episode of convergence occurred in the region at about 550 Ma, when previous structural elements of the East African Orogen were finally juxtaposed; and (ii) allow to extend models involving the polyphase assembly of Gondwana to East AfricaI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
