![]() Only minor normal faults can be identified in this upper sedimentary package. In particular, the M-reflector is slightly folded in the northern part of the basin, above two major faults, and sediments above the M-reflector are subhorizontal and thicken southward. However, not all faults seen beneath the M-reflector deform the upper Pliocene to Holocene sedimentary sequence. The structure of the Eastern Alboran Basin includes both extensional and compressional faults that converge downward on both sides of Al-Mansour Seamount, and the M-reflector is slightly folded above some of the faults ( Fig. The M-reflector can be traced across the whole section of the Eastern Alboran Basin and is considered to represent the base of the Pliocene-Pleistocene sedimentary sequences, a reference boundary for the interpretation of the structure of the Eastern Alboran Basin. The M-reflector is a very prominent feature in the Conrad 823 profile, because it separates two sedimentary sequences above (post-M) and below (pre-M) that exhibit a markedly different reflection character ( Fig. 2).īoth Sites 977 and 978 reached an upper Miocene unconformity correlated with the M-reflector. A southwest-northwest elongate, prominent volcanic high, the Al-Mansour Seamount, occupies the central part of the Eastern Alboran Basin, and Sites 977 and 978 were drilled to the south and north of this ridge, respectively ( Fig. The change in the trend coincides with the appearance of the narrow Yusuf Ridge. In the south, the Eastern Alboran Basin is flanked by the steep slope of the Habibas Escarpment, that trends west-northwest-east-southeast until 2 °W where it changes to a more east-west orientation. The northern flank is comprised of the rough, 1000-m-high Iberian slope where the Maimonides Ridge, a prominent volcanic high, forms the northern escarpment of the basin. The Eastern Alboran Basin is a 2000-m-deep, triangular-shaped, flat-bottomed basin that widens eastward from the Alboran Channel in the west to the larger South Balearic Basin in the east ( Fig. Most of these faults are presently active within the Ibero-Maghrebian region of distributed seismicity that is presently considered the plate boundary between Eurasia and Africa (e.g., Buforn et al., 1995). West-northwest- to east-southeast-striking right lateral faults are present in the Tell region (Morel and Meghraoui, 1996 Meghraoui et al., 1996), and the Yusuf Fault in the eastern Alboran Sea (Mauffret et al., 1987, 1992) correspond to this system. Northeast-southwest-striking faults in the Rif orogen of Morocco have a left lateral sense of movement. Minor northwest-southeast striking right lateral faults to the east of Málaga have been interpreted as the conjugate system to the Almería fault system (García-Dueñas et al., 1992 Balanyá, 1991). ![]() On the Iberian side, the northeast-southwest left lateral Carboneras fault system shows a minimum displacement of 25 km (Keller et al., 1995), belonging to a left lateral strike-slip fault system in the Almería area (Montenat, 1990). Some of these faults can be traced on shore where they have been studied in detail. Northeast-southwest- and northwest- to east-southeast-trending fault systems have left and right lateral sense of movement, respectively. The dominant strike-slip faults in the Alboran Basin form a northeast-southwest and west-northwest-east-southeast conjugate system with a 50-60 ° acute angle between the two strands ( Fig. STRIKE-SLIP STRUCTURAL STYLES STRIKE-SLIP STRUCTURAL STYLES
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