Four successive Late Pan-African dike suites are recognized in the central Elat area: (1) microdiorite and lamprophyre; (2) dacite porphyry with subordinate andesite and feldspathic (Fsp) rhyolite porphyry; (3) quartz porphyry and Fsp-rhyolite porphyry with minor trachydolerite and trachyandesite; (4) trachydolerite, mostly high-Ti. Dike swarms formed over the period of ∼600 Ma to 530 Ma. The dike episodes alternated with plutonic, volcanic, and sedimentary events. Microdiorite and lamprophyre from suite 1 correspond to calc-alkaline, medium- to high-K trachyandesite. Dacite porphyry is prevalent in suite 2 and forms together with augite-bearing andesite and rhyolite a high-K calc-alkaline series. In suite 3 silicic rocks are dominant; they are alkaline (NK/A >0.9) and have chemical characteristics of A-type granites. Among the trachydolerites from suites 3 and 4, high-Ti varieties are abundant (2.8-2.9 wt% and 3.3-4.5 wt% TiO2, respectively). Trachydolerites are enriched in REE, Zr, Y, Ti, and P. Although Late Pan-African dikes are postorogenic, magmas of the first two suites were derived from mantle sources that are characteristic of a subduction-related environment of active continental margins. Trachydolerites-3 and -4 were produced, however, from sources enriched in asthenospheric components. Late Pan-African dike swarms similar to those described in southern Israel are extremely abundant throughout the Sinai Peninsula and Eastern Desert of Egypt. Significant overlap of compositions in mafic dike rocks from southern Israel and the same rock types from southern Sinai suggest similar sequence and sources of dikes over a large region.
ASJC Scopus subject areas
- Earth and Planetary Sciences (all)