The Davie Fracture Zone: A recorder of continents drifts and kinematic changes
Roche, Vincent 1Ringenbach, Jean-Claude2
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作者信息
1. Sorbonne Univ
2. CSTJF
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Abstract
Transform continental margins play a major role in plate tectonics. In the last 10 years' petroleum exploration has moved to the hunt of stratigraphic traps in the passive margin sequence of continent-ocean transforms. The result has been a drastic increase in modern deep seismic data and more well calibrations. Considered as one of the longest continental transform plate boundaries, the Davie transform system (East of Africa) is one of the best places to investigate the evolution of a major transform linking two oceanic basins. Based on a new basement and structural maps and schematic cross-sections, our findings show that the Davie Fracture Zone (DFZ) is made of several transform segments with two main trending directions related to the plate scale kinematic reorganization occurring at ca. 155 Ma. The early proto-segments trend NW-SE in the oldest oceanic domain and are broadly in the same trend that onshore major faults and lineaments implying African structural inheritance. The second set of transform segments trends N-S and the most important corresponds to a plate boundary between the Mozambique Basin and the Madagascar margin. Results further show that the DFZ offers great variability of transpressional and transtensional structures and vertical displacements along its different segments from the onset of the transform activity until today. These main phases of inversion are also interpreted as a consequence of plate scale kinematic reorganizations. The DFZ is thus an excellent marker to follow the long-term evolution of plates tectonics, but also the short-term as attesting the presence of Neogene to present magmatic centers and active faults along the Mozambique coastline.
NSTL
Elsevier