Genesis of rhyolitic ignimbrites and lavas from distinct sources at a deep crustal level: field, petrographie, chemical and isotopic (Sr, Nd) constraints in the Tazekka volcanic complex (Eastern Morocco)

Geochemical and Sr–Nd isotopic constraints on the petrogenesis and geodynamic significance of the Jebilet magmatism (Variscan Belt, Morocco)

“…The evolution from continental lithospheric mantle signature in the Tanncherfi intrusive complex to the asthenospheric signature in the Jebilet massif, as well as in the Tazekka and Tichka massifs (Gasquet et al . 1992; Chalot-Prat, 1995), reflects a lithosphere being progressively heated from below (Houseman, McKenzie & Molnar, 1981; Nelson, 1992). Progressive replacement of the lithosphere by the asthenosphere results in elevated Moho temperatures and thus favours crustal melting at sequentially shallower levels (Fig.…”

The Carboniferous volcano-sedimentary depocentre of Tazekka Massif (Middle-Atlas, Morocco): new observations and geodynamic implications

“…Chalot-Prat and Cabanis (1989) and Chalot-Prat (1990) distinguish two groups of volcanic rocks. The first is composed of basic to andesitic homogeneous or hybrid rocks with an intraplate affinity and/or associated with an active continental margin; the second is essentially rhyolitic, of crystal origin (Chalot-Prat, 1995).…”

The pyroclastic dikes of the Tertiary San Luis Potosí volcanic field: Implications on the emplacement of Panalillo ignimbrite

“…The complex internal structure of the dikes observed in the CVSLP is not common in other reported dike areas. For example, Chalot-Prat et al (1995) mention that in the Tazekka volcanic complex east of Morocco, ignimbrite material filling the dikes is homogeneous. Chalot-Prat et al (1995) also consider that deposition of the pyroclastic flows can be ascribed to a violent release of vitroclastic material from deep fractures (as in the CVSLP).…”

“…The pyroclastic dikes have long, roughly tabular shapes. Different types of pyroclastic dikes have been reported in the literature (Chalot-Prat, 1995;Wolff, 1986;Ellwood and Wolff, 1985;Milanovski and Koronovski, 1965;Almond, 1971). They are considered feeding conduits of explosive eruptions, whose fragmentation and cooling occurred at depths <2 km (Wilson et al, 1980).…”

“…Pyroclastic dikes have been observed at the margins of deeply dissected cauldrons (Ekren and Bayers, 1976;Aramaki et al, 1977;Elston, 1984;Yoshida, 1984;Takahashi, 1986;Miura, 1997). In some cases they are related to strike-slip faults (Chalot-Prat, 1995). In general, pyroclastic dikes are associated to sub-volcanic structures.…”