Post-Variscan evolution of the Anti-Atlas belt of Morocco constrained from low-temperature geochronology

Gouiza, Mohamed; Charton, Rémi; Bertotti, Giovanni; Andriessen, P.A.M.; Storms, J.E.A.

doi:10.1007/s00531-016-1325-0

Cited by 57 publications

(83 citation statements)

References 97 publications

(128 reference statements)

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“…The major cooling event recorded during the Hauterivian–Aptian, which brought the basement rocks from mid‐crust to near‐surface temperatures, is consistent with low‐temperature thermochronology results from the Anti‐Atlas domain in the north (Gouiza, Charton, Bertotti, Andriessen, & Storms, ; Oukassou et al., ; Ruiz et al., ). It is also coherent with the presence of Lower Cretaceous sediments unconformably lying on the fringe of the Reguibat basement in the north (Figure ), although these sediments have yet to be properly dated.…”

Section: Methods and Analytical Resultssupporting

confidence: 78%

“…However, seismic data offshore the Dakhla margin indicate that our samples are located 400 to 500 km east of the margin hinge line and that the crust underneath the western Reguibat Shield is at least 27-30 km thick (Labails & Olivet, 2009). (El Jorfi et al, 2015) with respect to the maximum likelihood t-T path obtained from the thermal modelling and the regional tectonic events [a: Central Atlantic Rift (Klitgord, Schouten, Vogt, & Tucholke, 1986); b: South Atlantic Rift (Torsvik, Rousse, Labails, & Smethurst, 2009) The major cooling event recorded during the Hauterivian-Aptian, which brought the basement rocks from mid-crust to near-surface temperatures, is consistent with low-temperature thermochronology results from the Anti-Atlas domain in the north (Gouiza, Charton, Bertotti, Andriessen, & Storms, 2017;Oukassou et al, 2013;Ruiz et al, 2011). It is also coherent with the presence of Lower Cretaceous sediments unconformably lying on the fringe of the Reguibat basement in the north (Figure 1), although these sediments have yet to be properly dated.…”

Section: Thermal Modellingsupporting

confidence: 58%

“…The geological processes driving these thermal events/km‐scale vertical movements are unclear, especially since similar vertical movements are documented all along the Moroccan margin (e.g. Ghorbal et al., ; Gouiza et al., ; Malusà et al., ; Oukassou et al., ; Ruiz et al., ) and the East American conjugate as well (e.g. Grist & Zentilli, ; Roden‐Tice & Tice, ; Roden‐Tice & Wintsch, ).…”

Section: Methods and Analytical Resultsmentioning

confidence: 96%

“…The geological processes driving these thermal events/km-scale vertical movements are unclear, especially since similar vertical movements are documented all along the Moroccan margin (e.g. Ghorbal et al, 2008;Gouiza et al, 2017;Malus a et al, 2007;Oukassou et al, 2013;Ruiz et al, 2011) (Figure 1) is related to coeval regional shortening, documented by syn-sedimentary tectonics in the Essaouira basin, which is located in the western High Atlas to the south of the Meseta. Leprêtre et al (2017), on the other hand, proposed transient mantle dynamics to account for the major erosional phases recorded on both sides of the Atlantic.…”

Section: Thermal Modellingmentioning

confidence: 99%

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Mesozoic and Cenozoic thermal history of the Western Reguibat Shield (West African Craton)

Gouiza

Bertotti

Andriessen³

2018

Terra Nova

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Using low‐temperature thermochronology on apatite and zircon crystals, we show that the western Reguibat Shield, located in the northern part of the West African Craton, experienced significant cooling and heating events between Jurassic and present times. The obtained apatite fission track ages range between 49 and 102 Ma with mean track lengths varying between 11.6 and 13.3 μm and Dpar values between 1.69 and 3.08 μm. Zircon fission track analysis yielded two ages of 159 and 118 Ma. Apatite (U–Th)/He uncorrected single‐grain ages range between 76 and 95 Ma. Thermal inverse modelling indicates that the Reguibat Shield was exhumed during the Early Cretaceous, Late Cretaceous, Palaeocene–Eocene and Quaternary. These exhumation events were coeval with regional tectonic and geodynamic events, and were probably driven by a combined effect of plate tectonics and mantle dynamics.

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Section: Methods and Analytical Resultssupporting

confidence: 78%

Section: Thermal Modellingsupporting

confidence: 58%

Section: Methods and Analytical Resultsmentioning

confidence: 96%

Section: Thermal Modellingmentioning

confidence: 99%

See 2 more Smart Citations

Mesozoic and Cenozoic thermal history of the Western Reguibat Shield (West African Craton)

Gouiza

Bertotti

Andriessen³

2018

Terra Nova

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“…The lack of falling stage features and subsequently erosional unconformities suggest that the highstand system deposit occurred principally in a normal regressive conditions. This suggested tectonic control on vertical stacking sequences is documented by authors [25], [26] and [27] to explain the third and fourth order sea level fluctuations in particular basins as rifts, foreland and extensional intracratonic basins. The combined extensive tectonic event with a long term sea level rise, as suggested by [28] for the Cambrian time, is the main factor on building vertical stacking transgressive-regressive sequences in the Anti-atlas.…”

Section: Interpretation Of Stacking Sequence Unitsmentioning

confidence: 70%

Geodynamic Significance of Stacking Lower Cambrian Sequences Units in the Western Anti-Atlas

Benssaou¹

2017

IJMSA

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Abstract:In the Anti-Atlas the lower Cambrian succession was traditionally considered as a post-rift series. Recently the Western Anti-Atlas appears to be affected by an early Cambrian rifting process. In the Igherm area (Western Anti-Atlas), this succession is represented by an alternating carbonate and siliciclastic facies reflecting several sedimentary environments. The vertical stacking of these facies define four Composite-Sequences constituted, each one, by two or more transgressiveregressive sedimentary cycles. The differential and progressive extensional tectonic events seem to be the main control on the genesis and on the vertical stacking transgressive-regressive sedimentary cycles. The accommodation space is generated by a strong tilting related to syn-rift tectonics. The lack of lowstand system tracts and other erosive features, suggests the occurrence of platform drowning just below the falling sea level stage. So stratigraphic stacking of the Lower-Cambrian strata exposed in the Igherm area, constitutes the response to the rifting process in the Anti-Atlas and consequently a probably fragmentation indicator of a neoproterozoic Gondwana.

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Magnitude of rift‐related burial and orogenic contraction in the Marrakech High Atlas revealed by zircon (U‐Th)/He thermochronology and thermal modeling

2016

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The Atlas of Morocco is a continental rift developed during the Triassic‐Jurassic and moderately inverted during the Cenozoic. The High Atlas south of Marrakech, with exposures of basement and Triassic early synrift deposits, has been viewed as a high during the Mesozoic rifting. First zircon (U‐Th)/He ages and thermal models obtained from 42 samples in the Marrakech High Atlas following two NNW‐SSE transects across the mountain belt reveal that in contrast to previous models, the Triassic‐Jurassic rift was well developed in the Marrakech High Atlas (with more than 4.5–6 km of rift‐related deposits). Middle Jurassic‐Early Cretaceous zHe cooling ages obtained indicate that rift‐related subsidence in the Marrakech High Atlas finished in the Middle Jurassic and was followed by a period of exhumation where 2–3 km of rock were eroded. Thermal models from zHe data provide the first thermochronologic clue for a Late Cretaceous initiation of the Atlas compression‐driven exhumation in the inner parts of the Marrakech High Atlas. The Triassic‐Jurassic basin reconstruction assisted by thermochronology highlights a key role of inherited basement anisotropy in rift orientation and evolution, and on its subsequent inversion. Comparison of present‐day and restored sections to the rifting stage aided by thermochronology suggests minimum values of total orogenic shortening in the Marrakech High Atlas of 13 to 14 km (21 to 17%), with exhumation of 1 to more than 5 km of rocks. Similar zHe ages on both sides of the Tizi n'Test fault evince minor vertical movements along the fault during the Atlas orogeny.

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Post-Variscan evolution of the Anti-Atlas belt of Morocco constrained from low-temperature geochronology

Cited by 57 publications

References 97 publications

Mesozoic and Cenozoic thermal history of the Western Reguibat Shield (West African Craton)

Mesozoic and Cenozoic thermal history of the Western Reguibat Shield (West African Craton)

Geodynamic Significance of Stacking Lower Cambrian Sequences Units in the Western Anti-Atlas

Magnitude of rift‐related burial and orogenic contraction in the Marrakech High Atlas revealed by zircon (U‐Th)/He thermochronology and thermal modeling

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