Refined Tectonic Evolution of the Betic‐Rif Orogen Through Integrated 3‐D Microstructural Analysis and Sm‐Nd Dating of Garnet Porphyroblasts

Abstract

The detailed deformation history of the Betic-Rif orogen (Figure 1) and its relationship with distinct metamorphic events recognized in this belt are still ambiguous as is reflected in disparate tectonic models that still differ on such fundamental aspects as the timing and polarity of subduction zones, the role of crustal extension versus compression, or the emplacement history of several peridotite massifs exposed in the belt (e.g.

Pre‐Subduction Architecture Controls Coherent Underplating During Subduction and Exhumation (Nevado‐Filábride Complex, Southern Spain)

“…Li and Massonne (2018) identified Eocene monazite ages in the Mulhacén succession of the Sierra Nevada that support the Eocene 40 Ar/ 39 Ar data and suggest that the subduction of the NFC must have occurred prior to the Miocene metamorphic event. This was corroborated by Aerden et al (2022), who reported a late Eocene garnet Sm-Nd age (∼35 Ma).…”

“…In this study, the new age constraints from the NFC indicate that Alpujárride and the NFC were subducted at similar times. Since Alpujárride is currently on the hanging wall of low‐angle normal faults, Alpujárride must have been subducted first, followed by the NFC in a lateral continuation of the same subduction system as recently described by several studies (Aerden et al., 2022; Porkoláb et al., 2022; Poulaki & Stockli, 2022). Previous models suggest that the subduction of the NFC occurs much later in the Miocene (e.g., Van Hinsbergen et al., 2020); however, our data, along with recently published data (Aerden et al., 2022; B. Li & Massonne, 2018; Porkoláb et al., 2022), suggests that the subduction of the NFC is likely to have commenced around the Early Eocene (Figure 9).…”

“…Since Alpujárride is currently on the hanging wall of low-angle normal faults, Alpujárride must have been subducted first, followed by the NFC in a lateral continuation of the same subduction system as recently described by several studies (Aerden et al, 2022;Porkoláb et al, 2022;Poulaki & Stockli, 2022). Previous models suggest that the subduction of the NFC occurs much later in the Miocene (e.g., Van Hinsbergen et al, 2020); however, our data, along with recently published data (Aerden et al, 2022;B. Li & Massonne, 2018;Porkoláb et al, 2022), suggests that the subduction of the NFC is likely to have commenced around the Early Eocene (Figure 9).…”

“…More recently, Aerden et al. (2022) separated garnets based on their magnetic fraction and were able to obtain Sm‐Nd ages in Eocene (∼35 Ma) age as well as Miocene ones, and Porkoláb et al. (2022) with Ar/Ar data also found distinct events dated at 38–27 Ma and 22–12 Ma.…”

“…Li and Massonne (2018) proposed an HP/LT event during the Eocene (∼40 Ma) and a second P/T loop with exhumation from 24.1 ± 0.8 Ma. More recently, Aerden et al (2022) separated garnets based on their magnetic fraction and were able to obtain Sm-Nd ages in Eocene (∼35 Ma) age as well as Miocene ones, and Porkoláb et al (2022) with Ar/Ar data also found distinct events dated at 38-27 Ma and 22-12 Ma. The final exhumation of the NFC and Alpujárride was accommodated with the formation of low-angle normal faults and strike-slip transfer faults at ∼12 Ma for the NFC (Augier, Agard, et al, 2005;Azañón et al, 2015;Galindo-Zaldívar et al, 1993, 2003Madarieta-Txurruka et al, 2021;Platt et al, 2005;Reinhardt et al, 2007) and 22-18 Ma for Alpujárride (e.g., Platt et al, 2005).…”