Efeimazerta Fm

References: Claret & Tempère, 1968; Beuf et al., 1971; Klitzsch et al., 1973; Fabre et al., 1983

Synonym: Equivalent(s): Klitzsch et al. (1973) suggest that it could be equivalent to the Akakus Fm of the Murzuq/Djado basin.

It is essentially characterized by the presence of detrital levels, conglomeratic (poudingue quartzitic, intraformational conglomerates of red, green, or gray clays, reworked, breccias) and very ferruginous horizons (Figure). Despite significant lateral variations, the proportion of clayey sediments generally remains preponderant in the formation, giving it a morphology reminiscent of the underlying Silurian shales (Graptolitic Shales). According to Beuf et al. (1971), it could represent the correlative deposits of an erosion surface. Dolerite sills or flows are associated on the edge of the Adrar des Iforas and the Aïr; sometimes, levels of feldspathic sandstone or sandy shales are interstratified. Thickness is 15 m maximum.

[Fig. 1. Section of the Efeimazerta Fm north of Aïr (Source: Modified from Beuf et al., 1971, p. 112).]

Fluvio-Marine