The Sidi Ifni transect across the rifted margin of Morocco (Central Atlantic): Vertical movements constrained by low-temperature thermochronology

Abstract

The occurrence of km-scale exhumations during syn-and post-rift stages has been documented along Atlantic continental margins, which are also characterised by basins undergoing substantial subsidence. The relationship between the exhuming and subsiding domains is poorly understood. In this study, we reconstruct the evolution of a 50 km long transect across the Moroccan rifted margin from the western Anti-Atlas to the Atlantic basin offshore the city of Sidi Ifni. Low-temperature thermochronology data from the Sidi Ifni area document a ca. 8 km exhumation between the Permian and the Early/Middle Jurassic. The related erosion fed sediments to the subsiding Mesozoic basin to the NW. Basement rocks along the transect were subsequently buried by 1 to 2 km between the Late Jurassic and the Early Cretaceous. From late Early/Late Cretaceous onwards, rocks present along the transect were exhumed to their present-day position.

Exhumation and Surface Evolution of the Western High Atlas and Surrounding Regions as Constrained by Low‐Temperature Thermochronology

“…In the AA, AHe ages are older than 49.0 Ma (Sehrt, ), and AFT data are only concentrated along specific transects, and they are all older than 88 Ma (Gouiza et al, ; Malusà et al, ; Oukassou et al, ; Ruiz et al, ; Sehrt, ). Similar AHe (older than 66 Ma) and AFT (older than 121 Ma) cooling ages are also located further south and west with respect to our study area (Charton et al, ; Sehrt et al, ). AHe and AFT ages in the central HA indicate that these regions resided near the surface at low temperature below ~110–70 °C since the Mesozoic (Barbero et al, ).…”

“…The amount of deformation is analyzed along a large‐scale geologic cross section, where thermochronologic data across major faults can be used to quantify vertical offsets. To these goals, we provide new thermochronologic data over a large area within the HA and partly also over the AA, and we integrate them into the existing extensive thermochronologic data set (Balestrieri et al, ; Barbero et al, ; Charton et al, ; Domènech, ; Domènech et al, ; Ghorbal, ; Ghorbal et al, ; Gouiza et al, ; Leprêtre et al, ; Malusà et al, ; Missenard et al, ; Oukassou et al, ; Ruiz et al, ; Saddiqi et al, ; Sebti et al, ; Sehrt, ; Sehrt et al, ). We quantify the amounts and rates of exhumation using a simple age‐to‐erosion inversion method (Willett & Brandon, ), and we investigate cooling histories through thermal modeling QTQt (Gallagher, ).…”

Anticline growth by shortening during crustal exhumation of the Moroccan Atlantic margin

“…The Palaeozoic basement highs bounding the Essaouira-Agadir Basin, the Massif Ancien of Marrakech to the east, and the Jebilet to the northeast, experienced km-scale exhumation during the Late Jurassic-Early Cretaceous (Ghorbal, 2009;Saddiqi et al, 2009). Coeval exhumation events are also documented along the margin in the Meseta plateau to the north (Ghorbal, 2009;Saddiqi et al, 2009) and in the Anti-Atlas to the south (Malusà et al, 2007;Ruiz et al, 2011;Oukassou et al, 2013;Sehrt, 2014;Gouiza et al, 2017;Charton et al, 2018). This regional exhumation seems to have occurred during the post-rift stage of the Central Atlantic Ocean, i.e.…”

Evolution of the Ridges of Midelt‐Errachidia Section in the High Atlas Revealed by Paleomagnetic Data

“…Other authors (Beauchamp et al, ; Beauchamp et al, ; Bertotti & Gouiza, ) also admit uplifting of the Central High Atlas during this time, which would cause syn‐sedimentary deformations (also described, e.g., by Ettaki et al, and Gouiza et al, ). Finally, thermal modeling and interpretation of igneous intrusions (Gouiza et al, ; Charton et al, ) point to a relationship between transpression and magmatism, on one side, and to the exhumation of the onshore domain in the margin Atlantic of Morocco from Permian to Jurassic times, on the other.…”