The University of Manchester Research Intraplate uplift: new constraints on the Hoggar dome from the Illizi basin (Algeria) DOI: 10.1111/bre.12182 Document Version Accepted author manuscript Link to publication record in Manchester Research Explorer Citation for published version (APA): English, K., Redfern, J., Bertotti, G., English, J. M., & Yahia Cherif, R. (2016). Intraplate uplift: new constraints on the Hoggar dome from the Illizi basin (Algeria). Basin Research, 1. https://doi.org/10.1111/bre.12182 Published in: Basin Research Citing this paper Please note that where the full-text provided on Manchester Research Explorer is the Author Accepted Manuscript or Proof version this may differ from the final Published version. If citing, it is advised that you check and use the publisher's definitive version. General rights Copyright and moral rights for the publications made accessible in the Research Explorer are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Takedown policy If you believe that this document breaches copyright please refer to the University of Manchester’s Takedown Procedures [http://man.ac.uk/04Y6Bo] or contact [email protected] providing relevant details, so we can investigate your claim. Download date:11. Oct. 2021 Page 1 of 41 Basin Research 1 2 3 4 1 Cenozoic uplift of the Hoggar Region, North Africa: constraints from its 5 6 2 northern flank (Illizi basin, Algeria) 7 8 9 3 Kara L. English 10 4 Petroceltic International Plc, 5th Floor, 3 Grand Canal Plaza, Grand Canal Street Upper, Dublin 11 12 5 4, Ireland. Phone: +353 1 421 8300; E-mail: [email protected] 13 14 6 Jonathan ReDfern 15 16 7 School of Earth, Atmospheric and Environmental Sciences, University of Manchester, 17 18 8 Williamson Building, Oxford Road, Manchester, M13 9PL, United Kingdom; E-mail: 19 20 9 [email protected] 21 22 10 Giovanni Bertotti 23 24 11 Geoscience and Engineering, Delft University of Technology, Stevinweg 1, 2628CN, Delft, The 25 26 12 Netherlands; E-mail: [email protected] 27 28 13 Joseph M. English 29 th 30 14 Petroceltic International Plc, 5 Floor, 3 Grand Canal Plaza, Grand Canal Street Upper, Dublin 31 15 4, Ireland. Phone: +353 1 421 8300; E-mail: [email protected] 32 33 34 16 RachiDa Yahia Cherif 35 17 Direction Coordination Groupe Associations – Sonatrach, Djenane El-Malik, Hydra, Alger, 36 37 18 Algérie (Algeria); E-mail: [email protected] 38 39 40 19 Submitted to Basin Research, July 27th, 2015 41 42 20 Revision submitted to Basin Research, November 13, 2015 43 44 21 Second Revision submitted to Basin Research, January 3, 2016 45 22 Main text word count = 5960 46 47 23 Abstract word count = 182 48 49 24 Number of references = 85 50 51 25 Number of tables = 3 52 26 Number of figures = 7 53 54 27 Data Repository = Yes 55 56 28 Corresponding author = Kara English 57 58 1 59 60 FOR REVIEW PURPOSES ONLY Basin Research Page 2 of 41 1 2 3 29 ABSTRACT 4 5 30 Zones of anomalously high topography within continental interiors, distant from active plate 6 7 31 boundaries, are interpreted as being either dynamically supported by viscous flow in the 8 9 32 underlying mantle or influenced by plate tectonics. Constraining the models of their genesis 10 11 33 requires accurate data on the timing and dimensions of such features. New apatite fission-track 12 34 and thermal maturity data from the Illizi Basin in Algeria quantifies the magnitude and timing of 13 14 35 kilometre-scale uplift and exhumation of the northern flank of the Hoggar swell in North Africa. 15 16 36 The findings of this study, integrated with previously published thermochronological data, 17 18 37 confirm that long wavelength regional uplift occurred during the Cenozoic extending over a 19 38 distance in excess of 1,500 km from north to south. The uplift evidenced in the Hoggar Massif 20 21 39 significantly impacted the flanking Illizi and Tim Mersoï basins. The combination of thermal 22 23 40 history modelling and regional stratigraphic observations indicates that the onset of exhumation 24 25 41 of the Illizi Basin likely occurred during the Eocene, broadly coincident with magmatism on the 26 42 Hoggar Massif to the south and the onset of tectonic shortening in the Atlasic belt to the north. 27 28 29 43 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 2 59 60 FOR REVIEW PURPOSES ONLY Page 3 of 41 Basin Research 1 2 3 44 INTRODUCTION 4 5 6 45 Zones of anomalously high topography within continental interiors, far away from active 7 46 plate boundaries, are often interpreted as being dynamically supported by viscous flow in the 8 9 47 underlying mantle (e.g. Braun, 2010; Al-Hajri et al., 2009; Moucha & Forte, 2011; Jones et al., 10 11 48 2012). The average diameter of modern topographic swells across Africa and Antarctica is 1850 12 13 49 ± 450 km, and associated gravity anomalies suggest that the full height of dynamically supported 14 15 50 topography ranges from 800 to 1800 m (Jones et al., 2012). Long-wavelength basins and swells 16 51 characterize the present-day topography of Africa (Holmes, 1944; Burke, 1996). Northern Africa 17 18 52 is characterised by a number of prominent topographic swells, typically associated with 19 20 53 relatively young (c. 35 Ma-Recent) volcanism (e.g. Hoggar, Tibesti, Darfur; Fig. 1), consistent 21 22 54 with the involvement of sublithospheric processes (Sahagian, 1988; Wilson & Guiraud, 1992; 23 55 Burke, 1996; Liégeois et al., 2005; Azzouni-Sekkal et al., 2007; Beccaluva et al., 2007). 24 25 26 56 There is general consensus that mantle convection plays an important role in the formation 27 28 57 of many modern topographic swells, but detailed surface studies are required to establish the 29 58 timing and evolution of these uplifts in the geological record to provide constraints for 30 31 59 understanding their genesis. The Hoggar Massif in central North Africa (Fig. 1) is characterized 32 33 60 by exposed crystalline basement, and flanked by sedimentary basins. New apatite fission-track 34 35 61 and thermal maturity data from a well in the Illizi Basin (Well A; Fig. 1), along with basin 36 62 modelling and regional stratigraphic correlations, constrain both the timing and magnitude of 37 38 63 exhumation of the northern flank of the Hoggar Massif. These new data are integrated with 39 40 64 previously published thermochronological data from the Hoggar Massif and surrounding basins. 41 42 65 A regional cross-section is constructed from the Illizi and Berkine basins in the north, over the 43 66 Hoggar Massif, and southward across the Tim Mersoï and Iullemmeden basins (Fig. 1). This 44 45 67 illustrates that the Cenozoic kilometric-scale rock uplift occurred over a distance in excess of 46 47 68 1,500 km from north to south. 48 49 69 50 51 52 70 GEOLOGICAL SETTING 53 54 71 The Hoggar Massif in Algeria is associated with exposed Pan-African basement extending 55 2 56 72 over an area greater than 400,000 km (Fig. 1). The preserved Paleozoic sections north and south 57 58 3 59 60 FOR REVIEW PURPOSES ONLY Basin Research Page 4 of 41 1 2 3 73 of the Hoggar Massif have broadly similar stratigraphy, with up to 2.5 km of sedimentary section 4 5 74 preserved in the Illizi Basin (Galeazzi et al., 2010) to the north and in the Iullemmeden and Tim 6 7 75 Mersoï basins (Zanguina et al., 1998) to the south. A predominance of northerly paleocurrent 8 9 76 directions reported within Cambro-Ordovician and Devonian sandstones on the northern and 10 11 77 southern sides of the Hoggar Massif (Beuf et al., 1971) suggests that the Hoggar Massif was not 12 78 a structural high during the earlier part of the Paleozoic, and that sequences were originally 13 14 79 deposited continuously across the Hoggar region. Following the collision of Gondwana with 15 16 80 Laurasia, the Paleozoic sequence was variably uplifted and eroded across parts of northwest 17 18 81 Africa during the Late Carboniferous-Early Permian Hercynian (Variscan) Orogeny (Aliev et al., 19 82 1971; Burollet et al., 1978; Boote et al., 1998; Acheche et al., 2001). 20 21 22 83 Rifting along the northern margin of the African plate during the Early Triassic records the 23 84 initial breakup of Gondwana and the opening of the Tethyan seaway (e.g., Guiraud, 1998). 24 25 85 Triassic continental clastic systems sourced from uplifted Hercynian highs, flowed north- 26 27 86 northeast through the Berkine Basin towards the peri-Tethys (Turner et al., 2001). In response to 28 29 87 relative sea-level rise during the Middle Triassic, marine incursion occurred across Algeria, 30 31 88 Tunisia and western Libya leading to the formation of a restricted Triassic salt basin (Turner & 32 89 Sherif, 2007) in the northern portion of the Berkine and Oued Mya basins. Continued landward 33 34 90 encroachment during the Late Triassic and Early Jurassic resulted in the progressive southward 35 36 91 onlap of these successions onto older Paleozoic strata in the Illizi Basin (Galeazzi et al., 2010). 37 38 92 On the southern flank of the Hoggar Massif, the Iullemmeden Basin was also a site of 39 93 continental deposition during this time (Zanguina et al., 1998).