Magmatic Differentiation and Silica Saturation Trend in the Alkaline  Volcanic Suite of Jabal Al Hasawna, West Central LibyaMagmatic Differentiation and Silica Saturation Trend in the Alkaline  Volcanic Suite of Jabal Al Hasawna, West Central Libya

Malik Othman

doi:10.54172/zvtpy966

Authors

Malik Othman Department of Geology, Misurata University, Libya Author

DOI:

https://doi.org/10.54172/zvtpy966

Keywords:

Magmatic differentiation, Major elements, Volcanic, Al Hasawna, Phonolites

Abstract

Magmatic differentiation is one of the important factors that leads to the diversity seen in igneous rocks. This work aims to understand the processes that occurred in the alkaline magma that produced these volcanic rocks in the Jabal Al Hasawna region. The study was conducted as a follow-up to a preliminary report prepared by the Libyan Industrial Research Centre in 1978 on the volcanic rocks in the study area. The study concentrated on the major elements of the rocks being examined. The research paper is based on twenty-four samples, classified as one quartz-trachyte, five trachyte, nine phonolite and eight nepheline-phonolite samples. The work indicates that, through magmatic differentiation processes, an undersaturated alkaline melt differentiated into an oversaturated alkaline magma that formed volcanic lava flows, perhaps in multiple batches. The study concluded that differentiation processes occurred in the remaining magma, rather than primitive processes, claiming that the mantle signature may not have been present, although relying on major elements alone may not be sufficient to track this matter. Therefore, the study needs more data relating to rare elements, and this is one of the limitations of this work.

References

Abdelmoniem , M., & Mohamed, A. (2014). Composition and age of Cenozoic volcanism in Libya. PhD thesis. Scottish Universities Environment Research Centre (SUERC). http://theses.gla.ac.uk/5517.

Bordet, P., Freulon, J., & Le Franc, J. (1955). Phonolite a eudialyte du Jebel Fezzan. Bull. Soc. Franc. Min. Crist., 78, 425–31.

Busrewil, M., & Oun, K. (1991). Geo-chemistry of the Tertiary alkaline volcanic rocks of Jabal Al Hasawinah, Libya. In Third Symposium on the geology of Libya.

Capitanio, F., Faccenna, C., Funiciello, R., & Salvini, F. (2011). Recent tectonics of Tripolitania, Libya: an intraplate record of Mediterranean subduction. In: Van Hinsbergen,D.J.J., Buiter, S.J.H., Torsvik, T.H., Gaina, C., Webb, S.J. (Eds.), Formation and Evolution of Africa: A Synopsis of 3.8 Ga of Earth History: Geological Society London, Special Publications, 357, pp. 319–328.

Cox, K., Bell, J., & Pankhurst, R. (1979). The interpretation of igneous rocks. Allen and Unwin, London, p 450.

Elshaafi , A., & Gudmundsson, A. (2016). Volcano-tectonics of the Al Haruj volcanic province, central Libya. Journal of volcanology and geothermal research 325 (2016) 189-202.

Finlay , S., Abdelmoniem, M., & Darren, M. (2014). The origin of Cenozoic magmatism of Libya. Geophysical Research Abstracts Vol. 16, EGU2014-15877, 2014 EGU General Assembly 2014.

Goudarzi, G. (1980). Structure-Libya. In: Salem, M.J., Busrewil, M.T. (Eds.), The geology of Libya, vol. III. Academic Press, London, pp. 879–892.

Jurak, L. L. (1978a). Geological map of Libya 1:250,000 sheet Jabal Al Hasawanh NH 33-14, Explanatory booklet.

Klitzsch, E. (1968). Der basalt vulkanismus des Djebel Harudj, Ost-Fezzan, Libyen. In Vol. 57 (pp. 585-601). 1968, Stuttgart.

Lustrino, M., Cucciniello, C., Melluso, L., Tassinari, C. C., dè Gennaro, R., & Serracino, M. (2012). Petrogenesis of Cenozoic volcanic rocks in the NW sector of the Gharyan volcanic field, Libya. Lithos 155 (2012) 218–235.

Radivojevi´c, M., Eri´c, S., Turki, S. M., Tolji´c, M., & Cvetk, V. (2014). Textural and compositional characteristics of mantle xenoliths from southeastern Libya: Evidence of mantle refertilization processes. Geophysical Research Abstracts. Vol. 16, EGU2014-7945, 2014. EGU General Assembly 2014.