The Nkob talc deposit located in the central Anti-Atlas Pan-African belt is hosted by magnesian and siliceous metacarbonates in the contact aureole of the Ediacaran Amassine granite. It consists of a stratified succession of green serpentine-rich marbles, black dolomitic marbles, talcitites and phlogopitites (variously retrogressed into chloritites) enclosed within andalusite metapelite hornfels and quartzites. Two main metamorphic stages have been defined for the formation of the marbles and talcitites: (1) high-temperature recrystallization occurred under amphibolite facies conditions (>500 °C). Temperature increase during granite emplacement led to the formation of forsterite, tremolite, phlogopite (±diopside) bearing assemblages in siliceous marbles and to transformation of dolomitic (calcite-free) marbles from pure dolostones. This high temperature stage is also characterized by the growth of andalusite porphyroblasts in the metapelites surrounding the deposit. (2) A low temperature retrograde hydrothermal stage characterized by the reactive infiltration of aqueous silica-rich fluid (presumably derived from the granitic body), in greenschist facies conditions (<520 °C). Hydrous silicate minerals, mostly serpentine and talc (+calcite), were formed during this stage within the rocks (after fluid infiltration along grain boundaries) or within veins (marking channeled fluid circulation). Talc in ores formed by two processes at Nkob: acicular talc near the granite formed after the breakdown of tremolite in a temperature range of 350 to 500 °C, while tabular talc in the external aureole formed via reaction between dolomite and siliceous-aqueous fluids in temperatures below 350 °C. The different types of marbles derive from pure to slightly siliceous dolomite but green and green-black marbles were strongly affected by interactions with siliceous-aqueous fluids forming serpentine-phlogopite veins with calcite reaction zones. The talcitite layers were also affected by similar hydrothermal H2O-Si enrichment but their dolomitic precursor probably contained a more important detrital silicate fraction.