Main Strike-slip Fault Research Articles

O SISTEMA DE DOBRAMENTO APIAÍ, ESTADO DO PARANÁ

Folds belonging to this system are younger than the thrusting episodes that affected the Açungui Group, as indicated by the fact that they are outlined by S, foliation (which, in turn, is paralell to S,), as well as by the thrust faults, both strutures develloped through the first deformative event. The folds show different styles, including some with conical geometry. Axial plane foliation is a noticeable develloped feature but it is not penetrative all over the area; fold axis have a remarkable NE-S W direction and the axial planes are generally subvertical. These features are easily recognized in S, pole stereograms because they draw partial or full guirlands. Major folds were mapped and discussed in more detail. It is postulated here that this fold system could be an answer to second order compressive stress, oriented from NW to SE, associated to clockwise displacement along the main strike-slip faults in this area, with exception of the Setuva Antiform which cautiousness may be associated to a anti-clockwise (left-lateral) reactivation of the Lancinha strike-slip fault

A Natural Model of Active Transpressional Tectonics the en Échelon Structures of the Oriente Deep, Along the Northern Caribbean Transcurrent Plate Boundary (Southern Cuban Margin)

A seabearn and seismic reflection structural study of the Oriente Deep, located along the northern Caribbean transcurrent plate boundary, allows us to image in three dimensions active transpressional structures (cruise SEA-CARIB II, R/V Jean Charcot). These structures are folds and reverse faults. The folds display an en echelon arrangement and are set within three E-W trending alignments. The folds appear with an axis trending 30° to 40° to the shear direction. Their axes have undergone a rotation which gives them in plan a sigmoidal Zshape. The reverse faults formed after the folds and are located at the bases of the anticlines. The folding occurs outside the main strike-slip fault, above inactive burried faults affecting the basement of the Oriente Deep. The Oriente Deep is a exceptional natural model for the study of active transpressional deformation along a major strike-slip fault.

Phases tectoniques superposées dans les métasédiments Précambriens du domaine côtier occidental de la Cote d'Ivoire

Microstructural analysis of the coastal high-grade metasediments of the South Western Ivory Coast show at least four folding phases. The oldest phase does not seem to affect the lower Birrimian mesometamorphic series and it is concluded that this phase affected a pre-Eburnean crystalline and granitic basement. The name Liberian has been applied in the Ivory Coast to this basement. The Birrimian mesometamorphic rocks record the three youngest folding phases: two of them may correspond to two major north north east to south south west synmetamorphic phases of the Eburnean orogeny. The last phase is clearly post-Eburnean and may be synchronous with the north west south east trending chevron-folds (with crenulated schistosity) and the main north north east strike slip faults of the West African shield in the Ivory Coast.