The Cryogenian arc formation and successive high-K calc-alkaline plutons of Socotra Island (Yemen)

Type Article
Date 2012-09
Language English
Author(s) Denele Y.1, 2, 7, Leroy S.7, Pelleter EwanORCID3, Pik R.4, Talbot J-Y.6, Khanbari K.5
Affiliation(s) 1 : Univ Toulouse, CNRS IRD OMP, GET, F-31400 Toulouse, France.
2 : Univ Montpellier 2, UMR CNRS 5243, Geosci Montpellier, F-34095 Montpellier, France.
3 : IFREMER, Ctr Brest, F-29280 Plouzane, France.
4 : Nancy Univ, CNRS, CRPG, F-54501 Vandoeuvre Les Nancy, France.
5 : Geol Survey, Sanaa, Yemen.
6 : CREGU, F-54501 Vandoeuvre Les Nancy, France.
7 : UPMC Univ Paris 06, UMR 7193, ISTEP, F-75005 Paris, France.
Source Arabian Journal Of Geosciences (1866-7511) (Springer Heidelberg), 2012-09 , Vol. 5 , N. 5 , P. 903-924
DOI 10.1007/s12517-011-0476-3
WOS© Times Cited 14
Keyword(s) Neoproterozoic, East African-Antartic Orogen, Arabian-Nubian shield, Socotra Island, Andean-type arc, Back-arc basin
Abstract The Socotra Island belongs to the southern rifted margin of the Gulf of Aden and occupied in Neoproterozoic times a key position to constrain the age and the nature of the largely hidden Neoproterozoic rocks of the Arabian plate. Our integrated field, petrographic, geochemical and geochronological study in the Neoproterozoic rocks recognises three main successive events: (a) high-temperature ductile deformation and metamorphism forming probably in a compressive or transpressive regime; (b) mafic to intermediate intrusions as vertical sheets, kilometre-scale gabbro laccoliths, mafic dike swarm and lavas which present mainly a depleted arc signature with some evidences of evolution from an enriched-arc signature; (c) felsic intrusions mainly composed of highly potassic calc-alkaline and pinkish granites dated between 840 and 780 Ma. Relationships between the various petrographic types and U-Pb data suggest that these events occurred during a relatively short time span (80 Ma at max). Earlier high-temperature-low-pressure metamorphism stage as well as geochemical signature of mafic rocks show that development of Cryogenian formations of Socotra were controlled successively by an Andean-arc and a back-arc setting. These features cannot be easily reconciled with those of the Arabian-Nubian shield to the west of Socotra and of the Mozambique Belt to the south. We propose that the Socotra basement was developed at an active margin close to the India block in Cryogenian times.
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