The residual melts that remained after the consolidation of the Jálama batholith crystallized to form a group of intra-granitic pegmatite dykes, which are hosted by its outermost facies (the External Unit), and the most evolved residual melts migrated through fractures to form the Cruz del Rayo field of pegmatite dykes, which are hosted by pre-Ordovician low-grade metasedimentary rocks. The increasing activity of phosphorus as magmatic differentiation took place led to the crystallization of primary phosphates, including members of the triplite–zwieselite and the amblygonite–montebrasite series. A strong albitization of the granitic and pegmatite rocks led to the replacement of the primary assemblage by other phosphates such as alluaudite. The influx of post-magmatic hydrothermal fluids, produced quartz veins, gave rise to the crystallizationof ore minerals and triplite, and altered the granites, aplites and pegmatites, replacing some of the phosphate minerals and feldspars and depositing goyazite, montebrasite and childrenite–eosphorite. The interaction of the residual hydrothermal fluids with those from the surrounding metamorphic rocks during later alteration events resulted in the influx of large quantities of Ca and Mg, and produced phosphate assemblages enriched in those elements. Finally, late goyazite, hydroxylapatite and an unidentified Fe-rich phosphate were formed as a result of supergene alterationby percolating meteoric waters, which added Ca, Sr and other elements into the system, and increased fO2.

In the Variscan fold belt of Morocco, the Jebilet massif is characterized by Palaeozoic metasedimentary rocks intruded by syntectonic magmatism that includes an ultramafic–granitoid bimodal association and peraluminous granodiorites emplaced c. 330 Ma, intruded by younger leucogranites c. 300 Ma. The mafic–ultramafic rocks belong to a tholeiitic series, and display chemical and isotopic signatures consistent with mixing between mantle-derived and crust-derived magmas or assimilation and fractional crystallization. The granites within the bimodal association are mainly metaluminous to weakly peraluminous microgranites that show characteristics of A2-type granites. The peraluminous, calc-alkaline series consists mainly of cordierite-bearing granodiorites enclosing magmatic microgranular enclaves and pelitic xenoliths. Detailed element and isotope data suggest that the alkaline and the peraluminous granitoids were formed in the shallow crust (<30 km) by partial melting of tonalitic sources at high temperatures (up to 900°C) and by partial melting of metasedimentary protoliths at relatively low temperatures (c. 750°C), respectively. Mixing between the coeval mantle-derived and crust-derived magmas contributed to the large variation of initial εNd values and initial Sr isotopic ratios observed in the granitoids. Further contamination occurred by wall-rock assimilation during ascent of the granodioritic plutons to the upper crust. The ultramafic–granitoid association has been intruded by leucogranites that have high initial Sr isotopic ratios and low initial εNd values, indicating a purely crustal origin. The heating events that caused emplacement of the Jebilet magmatism are related to cessation of continental subduction and convective erosion/thinning of the lithospheric mantle during plate convergence.