Exhumation of the Ronda Peridotite During Hyper‐Extension: New Structural and Thermal Constraints From the Nieves Unit (Western Betic Cordillera, Spain)

Abstract

First order non-cylindricity or coexistence of interacting large-scale thrust and extensional shear zones are common features in small orogens hosted in the Mediterranean realm. The tight Betic-Rif arc is typical of this situation where Africa-Eurasia plate convergence strongly interferes with 3-D subduction dynamics to produce a complex crustal-scale tectono-metamorphic evolution (

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

“…Because apatite grains from Sierra Nevada are fully reset, the partially recrystallized apatite from Sierra de los Filabres and Sierra Alhamilla might indicate that these rocks experienced lower peak temperatures. Similar temperature variations between the Betic orogens have been previously observed in both the NFC and Alpujárride with higher temperatures in the west and lower in the eastern domains (Bessière et al., 2022; Bessière, Augier, et al., 2021; Bessière, Jolivet, et al., 2021; Platt et al., 2006). Additionally, different P / T conditions have also been observed among units in the same localities, which results in a discrepancy among P / T work done in the area as compiled by Santamaría‐López et al.…”

“…After the HP/LT event, fine‐grained Permo‐Triassic schists of the Alpujárride may have experienced 400°C and 0.3–0.4 GPa in the Miocene (Azañón & Crespo‐Blanc, 2000; Bakker et al., 1989; Monié et al., 1991; Platt et al., 2005). Even though the P / T conditions of Alpujárride and the NFC are different, the timing of the metamorphic events is similar (Bessière et al., 2022; Bessière, Augier, et al., 2021; Bessière, Jolivet, et al., 2021). Additionally, Poulaki & Stockli (2022) showed that the NFC and Alpujárride have nearly identical sedimentary provenance signatures and were likely deposited nearby in similar tectonic settings, showing a close affinity between the Internal Betic terranes.…”

“…The first HP/LT metamorphic event is evidenced by the presence of carpholite, kyanite, chloritoid, and aragonite (Azañón & Crespo‐Blanc, 2000; Booth‐Rea et al., 2002, 2005). Pressure and temperature estimates yield 400 ± 100°C and 1 ± 0.2 GPa (Azañón & Crespo‐Blanc, 2000; Platt et al., 2013) with an estimated timing of Eocene (e.g., Bessière et al., 2022; Bessière, Augier, et al., 2021; Bessière, Jolivet, et al., 2021; Marrone et al., 2021; Monié et al., 1991; Platt et al., 2005). After the HP/LT event, fine‐grained Permo‐Triassic schists of the Alpujárride may have experienced 400°C and 0.3–0.4 GPa in the Miocene (Azañón & Crespo‐Blanc, 2000; Bakker et al., 1989; Monié et al., 1991; Platt et al., 2005).…”

“…The tectonic processes that led to the closure of the Neo‐Tethys ocean in the western Mediterranean and the Betic‐Rif orogen are currently debated, with scenarios including (a) a northwest‐dipping subduction zone (e.g., Bezada et al., 2013; Booth‐Rea et al., 2007; Brun & Faccenna, 2008; Carminati et al., 2012; Chertova et al., 2014; Faccenna et al., 2004; Rosenbaum et al., 2002), (b) An east‐dipping subduction zone followed by reversal and northwest‐dipping subduction (Frizon de Lamotte et al., 2000; Rehault et al., 1984), (c) a south‐east dipping subduction zone (Behr & Platt, 2012) or (d) contemporaneous southward and northward two‐sided subduction (Bessière, Augier, et al., 2021; Bessière, Jolivet, et al., 2021; Vergés & Fernàndez, 2012). Regardless of the initial direction of subduction, many studies agree on the subsequent rotation of the system with east‐dipping subduction and westward trench retreat.…”

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

“…Bessière, Augier, et al. (2021) recently called for further exploration of this model after reinterpreting a small tectonic window of Blanca‐Unit rocks as a Los Reales klippe (Robledal Klippe).…”