Timing of Alpine Orogeny and Postorogenic Extension in the Alboran Domain, Inner Rif Chain, Morocco

Abstract

Orogeny is the process through which continental crust grows and differentiates at convergent plate margins. Understanding the tectonic structures and the temporal scales involved in the formation and the destruction of orogenic belts is the prerequisite to decrypt the geodynamic environments that control the transition from plate convergence to divergence and, ultimately, the cycles of continental assembly and breakup (e.g., Brown, 2010).The study of the exhumed roots of the Alpine orogen in the Mediterranean region (Figure 1a) has fostered the advancement of knowledge on the geological processes and mechanisms operative during the transition from crustal shortening to extension at convergent plate margins (

Two Cenozoic Extensional Phases in Mallorca and Their Bearing on the Geodynamic Evolution of the Western Mediterranean

“…Oligocene to Early Miocene extension has been described at different lithospheric depths in the part of the Alboran domain that now crops out in the Internal Betics, for example in the Ronda subcontinental peridotite sequence (Bessière et al., 2021; Booth‐Rea et al., 2005; Garrido et al., 2011; Precigout et al., 2013); or at shallower crustal depths, with low‐angle normal faults and detachments denudating the Paleogene Alpujarride‐Sebtide‐Malaguide thrust stack (Booth‐Rea et al., 2004, 2005; Lonergan & Platt, 1995; Marrone et al., 2021). This extension affected the AlKa segment of the AlKaPeKa orogenic domain, formed during the Late Cretaceous to Palaeogene, whose hinterland is expressed as the BP (Figure 13).…”

“…Rif (Bessière et al, 2021;Marrone et al, 2020Marrone et al, , 2021Platt et al, 2005), the Calabrian-Peloritani ranges (Heymes et al, 2010;Rossetti et al, 2001Rossetti et al, , 2004, the Kabylies (Bruguier et al, 2017), andCorsica (Di Vincenzo et al, 2016;Martin et al, 2011;Rossetti et al, 2015;Vitale Brovarone & Herwartz, 2013). Eocene Ar-Ar in phengite and U-Th-Pb in monazite radiometric ages are likewise obtained from the Nevado-Filabride complex at the core of the Betics (Augier, Agard, et al, 2005;Li & Massonne, 2018).…”

“…Remains of the AlKa orogen segment are now represented by the Alpujarride-Malaguide and Sebtide-Ghomaride thrust stacks in the Betics and Rif, formed by continental rocks compatible with a North Iberian Massif origin, according to detrital zircon age populations; thus they would correspond to the nearby Paleozoic sequence of Menorca and the Catalan Coastal Ranges (Azdimousa, Jabaloy-Sánchez, Talavera, et al, 2019;Jabaloy-Sánchez et al, 2021;Martínez et al, 2016). The lower plate of this continental subduction system was represented by the Alpujarride-Sebtide complex, which underwent HP/LT metamorphism (e.g., Azañón et al, 1997;Booth-Rea et al, 2002;Goffé et al, 1989) dated as Paleocene-Eocene based on Ar/Ar in phengite (Bessière et al, 2021;Marrone et al, 2020Marrone et al, , 2021Platt et al, 2005). The Ronda peridotite represents the subcontinental lithospheric section of the Alpujarride, and probably reached its primary conditions recorded in garnet lherzolite facies under 2.4-2.7 GPa and 1020°C-1100°C at this time (Garrido et al, 2011;Figure 13).…”

“…At an early stage of this renewed contractive reorganization, the Alpujarride complex underwent its final northward-directed thrusting phase, involving the previously thinned Alpujarride section (Azañón et al, 1997;Balanyá et al, 1997Balanyá et al, , 1998Booth-Rea et al, 2005;Simancas, 2018). Between the Early and Middle Miocene, the final exhumation of the Alboran Domain-formed by the Malaguide-Ghomaride and Alpujarride-Sebtide complexes-occurred atop the orogenic wedge (e.g., Booth-Rea et al, 2004;García-Dueñas et al, 1992;Lonergan & Johnson, 1998;Lonergan & Platt, 1995;Platt et al, 2003Platt et al, , 2005Marrone et al, 2021; Figure 15). Extension coeval to FTB development at the front of the orogenic wedge is a common feature of the Western Mediterranean orogens (e.g., Jolivet et al, 1994;Martínez-Martínez & Azañón, 1997;Platt & Vissers, 1989;Rossetti et al, 1999) that has been related to roll-back of subducted Tethys lithosphere segments (Faccenna et al, 2004;Lonergan & White, 1997) presently imaged as mantle lithospheric slabs under the Western Mediterranean (Bezada et al, 2013;Fichtner & Villaseñor, 2015;Piromallo & Morelli, 2003;Wortel & Spakman, 2000).…”

Tectonic Evolution of the Nevado‐Filábride Complex (Sierra de Los Filábres, Southeastern Spain): Insights From New Structural and Geochronological Data

“…The first solution considers Paleogene burial followed by slow exhumation during the Miocene, hence relating Miocene ages to exhumation Bessière, 2019;Bessière et al, 2022;Li & Massonne, 2018;Monié et al, 1991). This interpretation correlates the NFC with the same paleogeographic continental unit as the AC and MC or the Upper Sebtides in the Moroccan Rif belt (AlKaPeCa unit, Bouillin et al, 1986), which record similar Paleogene ages of metamorphism (Bessière et al, 2022;Marrone, Monié, Rossetti, Aldega et al, 2021;Marrone, Monié, Rossetti, Lucci et al, 2021;Monié et al, 1994;Platt et al, 2005). This solution is consistent with currently available kinematic and P-T data; however, it is difficult to reconcile with the very limited (<100 km) convergence in the Eocene, considering that all three of the AC, Ophiolite unit, and continental NFC must be stacked and subducted below the MC.…”