Subsidence analyses from the Betic Cordillera, southeast Spain

Abstract

Fifty-four Mesozoic±Cenozoic stratigraphic sections from the Betic Cordillera of southeast Spain have been analysed in order to estimate the timing and amount of lithospheric stretching that occurred at the western end of the Tethyan Ocean since the Hercynian Orogeny. The standard backstripping technique has been used in order to calculate the water-loaded subsidence of basement for each section. Water-loaded subsidence curves were then inverted in order to determine the variation of lithospheric strain rate as a function of time, which yields estimates of timing, magnitude and intensity of stretching.Rifting commenced during the Late Permian/Early Triassic times and continued intermittently throughout the Mesozoic in response to the opening of the Tethyan Ocean to the east and the opening of the Atlantic Ocean to the west. Two major events in the Permo-Triassic/Early Jurassic and the Late Jurassic/Early Cretaceous can be clearly identified. Stretching factors are generally small (1.1±1.25) probably because the Betic Cordillera was located at the westernmost end of the Tethys.Peak strain rates of~10 À15 s À1 were obtained for Mesozoic rift events and these values are in broad agreement with those obtained throughout the Tethyan Realm. We have also analysed the Neogene extensional event, which played an important role in forming the existing Mediterranean Sea. A combination of well-log information and calibrated seismic reflection data was modelled. Peak strain rates in these younger basins are almost one order of magnitude faster than those estimated for the Mesozoic basins. These higher values appear to be typical of back-arc extensional basins elsewhere. To the west and north of the Betic Cordillera, the Guadalquivir foreland basin developed as extension took place further east. Backstripped sections from this basin clearly record the northward migration of foreland basin subsidence through time.

The Betic Ophiolites and the Mesozoic Evolution of the Western Tethys

“…This ocean was unrelated to the oceanic systems represented by the Dinarides and Hellenides ophiolites, which developed eastward and concomitant with active subduction processes. This hypothesis is not based only on ophiolite investigations, but is supported by facies analyses and paleontological studies of coeval sedimentary sequences (Tendero et al [39]; Lemoine et al [43]; Lagabrielle et al [44]; Principi et al [77]; Perez-Lopez and Perez-Valera [94]; Critelli et al [95]; Hanne et al [96]; Martin-Rojas et al [97]; Somma et al [98]; Zaghloul et al [99]). …”

Mesozoic thermal history of the Prebetic continental margin (southern Spain): Constraints from apatite fission-track analysis

“…Reviews on the main aspects of the Betic margin can be found in Vera (2001) and Martín-Chivelet et al (2002) and references therein. Hanne et al (2003) have recently analysed the subsidence throughout the entire Betic cordillera. Nevertheless, certain aspects concerning the geological history of the Prebetic margin, such as the thermal evolution from Mesozoic to present, were considered for the first time only recently (Barbero et al, 2001).…”

Geology of the Eastern Prebetic Zone at the Jumilla region (SE Iberia)

“…Extension in the South Iberian margin which took place between the Lower and Middle Jurassic was clearly connected with the opening of the Central Atlantic Ocean to the west (De Jong, 1990;Srivastava et al, 1990). Therefore, the following Upper Jurassic to Santonian extension could be related to the continued opening of the Central Atlantic and synchronous development of extensional basins in the Western Tethyan area (Hanne et al, 2003;Ziegler, 1989). Examples of Mesozoic extension (i.e.…”

“…As a result, a thickened Miocene succession was deposited in the Matamoros Basin. This late extension could be related to the late Oligocene to Miocene extension that took place in the western Mediterranean region, in the Alboran Sea and in the Valencia Trough (Hanne et al, 2003;Maillard & Mauffret, 1999;Roca & Guimerà, 1992;Torné & Banda, 1992). In addition, the combined effect of the Campanian to Aquitanian contractional reactivation of pre-existing salt structures and the Miocene extensional reactivation conducted by the NE-dipping Maestre Fault, triggered passive salt extrusion of La Rosa and Jumilla diapirs ( Figure 4(b,c)).…”

“…The Alpine Tethys resulted from the Lower to Middle Jurassic rifting followed by the Callovian oceanic flooring that separated the Eurasian and African plates (Schettino & Turco, 2011). However, in the External Betic Zones, the most important rifting phase occurred later allowing the deposition of the Upper Jurassic to Santonian syn-extensional sediments unconformably above the pre-extensional Lower and Middle Jurassic carbonates (De Ruig, 1992; García-Hernández, López-Garrido, Rivas, Sanz de Galdeano, & Vera, 1980;Hanne, White, & Lonergan, 2003;Vera, 2001). During the Upper Jurassic to Santonian, the External Betic Zones (Figure 2) were subdivided into the northwestern Prebetic Zone and the southeastern Subbetic Zone (García-Hernández et al, 1980).…”