The Davie Fracture Zone: A recorder of continents drifts and kinematic changes
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.
Origin | Files produced by the author(s) |
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