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ABSTRACT The southwestern part of the western Mediterranean
Alboran Basin, including part of the Alboran ridge (Xaouen Bank), was investigated
through the analysis of 28 intersecting multichannel seismic lines. The
seismic stratigraphy is tied to the Amoco well El-Jebha 1. Five seismic
units or subunits are described from the Quaternary to the middle (and
lower?) Miocene. The acoustic basement is interpreted to be mainly Paleozoic
and Triassic metamorphic rocks of the Alboran Domain nappes, and, in places,
middle Miocene-Messinian calc-alkalic volcanics. In the depocenters, the
thickness of the sedimentary infill (mostly clays and turbidites) exceeds
9 km. Normal faults of middle Miocene-Tortonian age are broadly parallel
to the coast, and dip either
seaward or landward. They were mostly inverted
during pre- and post-Messinian episodes of compression, which formed a
set of en echelon, north-verging faulted folds in the Alboran ridge area,
in relation with sinistral movement along the offshore projection of the
Jebha fault. After Pliocene subsidence, a final episode of compression
reactivated the earlier folds and pushed the Alboran ridge onto the Moroccan
slope. The complex structural history suggests many structural and stratigraphic
potential hydrocarbon traps. A high-resolution seismic survey could lead
to the definition of new exploration plays. |
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