Petrology, Geochemistry and Petrogenesis of the Sidi El Hemissi Triassic ‘Ophites’ (Souk Ahras, NE Algeria)

Laouar, R., Zanouda, H. S., Salmi-Laouar, S., Sebai, A., Verati, C., Bouhlel, S. and Boyce, A. J. (2019) Petrology, Geochemistry and Petrogenesis of the Sidi El Hemissi Triassic ‘Ophites’ (Souk Ahras, NE Algeria). In: Petrogenesis and Exploration of the Earth’s Interior Proceedings of the 1st Springer Conference of the Arabian Journal of Geosciences (CAJG-1), Hammamet, Tunisia, 12-15 Nov 2019, pp. 13-16. ISBN 9783030015756 (doi:10.1007/978-3-030-01575-6_3)

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Abstract

Sited in Souk-Ahras, the Sidi El Hemissi region stands as part of the Tellian Atlas, where the Triassic formation tectonically outcrops under the Tellian nappes of the Maghrebide chain. Dubbed ‘ophites’, mafic rocks, mainly gabbros and dolerites are interbedded in ~200 × 30 m lenticular body within the Triassic gypsum-rich formation. These rocks are composed of plagioclase, amphibole, pyroxene and scarce olivine crystals. Albitization represents the major alteration process, though chloritization, calcitization and epidotization of ferromagnesian minerals are also perceived. The geochemical observations prove to reveal that these mafic rocks exhibit medium- to low-Ti continental tholeiitic basalt affinity. They are enriched in LILE and LREE, as compared to HFSE and HREE, and display enriched-mid-ocean ridge basalt (E-MORB)-like incompatible element patterns in primitive mantle-normalized multi-element pattern. The weak Nb anomaly, along with the medium- to low-Ti contents, suggests possible interaction between an enriched mantle source-derived magma and lower crustal rocks. These chemical features display high similarities with those sited in the central Atlantic magmatic province (CAMP) of upper Triassic–lower Jurassic age. Hence, they turn out o be considered as highly linked to the western branch of the Alpine Tethys system, geologically and tectonically associated with the Central Atlantic Ocean opening.

Item Type:Conference Proceedings
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Boyce, Professor Adrian
Authors: Laouar, R., Zanouda, H. S., Salmi-Laouar, S., Sebai, A., Verati, C., Bouhlel, S., and Boyce, A. J.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
ISSN:2522-8714
ISBN:9783030015756
Published Online:23 February 2019

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