5.1 Introduction
The paleogeography of a marine basin is strongly controlled by its geodynamic
evolution, particularly in the case of active basins such as the Alboran Sea. Tectonics
are responsible for the widening or narrowing of the marine basin, the modification
of bottom surface reliefs through the creation of subsidence zones that can evolve to
sedimentary sub-basins, or the formation of positive reliefs—by tectonic deformation, volcanic activity, and diapirism, and even the generation and destruction of
oceanic gateways and/or straits to adjacent seas. The modification and formation of
such physiographic reliefs can give rise to critical situations for the habitat. Closure
of a strait can mean the isolation of biological populations between adjacent seas and
could favor the development of endemic species or of new relationships among
species. In turn, the opening of gateways can generate episodes of colonization or
invasion by non-native species that may leave a print on the biological history of the
basin. Therefore, sound knowledge of the geological and geodynamic evolution of a
marine basin is needed to face problems involving its current biogeography.
The Alboran Basin is a Neogene-Quaternary basin formed since the late Oligocene through extensional processes, located within the Betic-Rif alpine cordillera
and forming part of this orogenic system. The Betic-Rif belt is characterized onland
by ranges that form a tight orocline at the junction between the Atlantic Ocean and
the Mediterranean Sea. At present, the Alboran Basin has relatively small dimensions, both in length and width (Chap. 6). The basin has been progressively restricted
in the last 10 Ma (Tortonian) due to uplift of the adjacent mountainous reliefs,
producing the isolation of intramontane and foreland basins (onland) in addition to
the current Alboran Sea. Other changes in the basin’s dimensions can be traced to
shifts in the sea level, most notably desiccation during the Messinian salinity crisis,
and eustatism in Pliocene-Quaternary times.
Nowadays, the Alboran Basin is situated along the boundary between the current
plates of Africa and Eurasia (Fig. 5.1), and it occupies a strategic position from an
ecological/oceanographic standpoint: this basin harbored the connection of water
masses and biological populations from the Atlantic Ocean and the Mediterranean
Sea.
Thus, ongoing tectonics and the geodynamic evolution tied to differential kinematics of the African and Eurasian plates, plus the Alboran Domain’s westward drift
since the late Oligocene, are key factors in the configuration of the current basin and
continental margins. They likewise determine Atlantic-Mediterranean oceanic
M. Benmakhlouf
Faculty of Sciences, Université Abdelmalek Essaadi, Tetouan, Morocco
e-mail: mbenmakhlouf@uae.ac.ma
Y. Martos
NASA Goddard Space Flight Center, University of Maryland College Park, Greenbelt, MD,
USA
e-mail: yasmina.martos@nasa.gov
112
J.-T. Vázquez et al.
The paleogeography of a marine basin is strongly controlled by its geodynamic
evolution, particularly in the case of active basins such as the Alboran Sea. Tectonics
are responsible for the widening or narrowing of the marine basin, the modification
of bottom surface reliefs through the creation of subsidence zones that can evolve to
sedimentary sub-basins, or the formation of positive reliefs—by tectonic deformation, volcanic activity, and diapirism, and even the generation and destruction of
oceanic gateways and/or straits to adjacent seas. The modification and formation of
such physiographic reliefs can give rise to critical situations for the habitat. Closure
of a strait can mean the isolation of biological populations between adjacent seas and
could favor the development of endemic species or of new relationships among
species. In turn, the opening of gateways can generate episodes of colonization or
invasion by non-native species that may leave a print on the biological history of the
basin. Therefore, sound knowledge of the geological and geodynamic evolution of a
marine basin is needed to face problems involving its current biogeography.
The Alboran Basin is a Neogene-Quaternary basin formed since the late Oligocene through extensional processes, located within the Betic-Rif alpine cordillera
and forming part of this orogenic system. The Betic-Rif belt is characterized onland
by ranges that form a tight orocline at the junction between the Atlantic Ocean and
the Mediterranean Sea. At present, the Alboran Basin has relatively small dimensions, both in length and width (Chap. 6). The basin has been progressively restricted
in the last 10 Ma (Tortonian) due to uplift of the adjacent mountainous reliefs,
producing the isolation of intramontane and foreland basins (onland) in addition to
the current Alboran Sea. Other changes in the basin’s dimensions can be traced to
shifts in the sea level, most notably desiccation during the Messinian salinity crisis,
and eustatism in Pliocene-Quaternary times.
Nowadays, the Alboran Basin is situated along the boundary between the current
plates of Africa and Eurasia (Fig. 5.1), and it occupies a strategic position from an
ecological/oceanographic standpoint: this basin harbored the connection of water
masses and biological populations from the Atlantic Ocean and the Mediterranean
Sea.
Thus, ongoing tectonics and the geodynamic evolution tied to differential kinematics of the African and Eurasian plates, plus the Alboran Domain’s westward drift
since the late Oligocene, are key factors in the configuration of the current basin and
continental margins. They likewise determine Atlantic-Mediterranean oceanic
M. Benmakhlouf
Faculty of Sciences, Université Abdelmalek Essaadi, Tetouan, Morocco
e-mail: mbenmakhlouf@uae.ac.ma
Y. Martos
NASA Goddard Space Flight Center, University of Maryland College Park, Greenbelt, MD,
USA
e-mail: yasmina.martos@nasa.gov
112
J.-T. Vázquez et al.