A critical study of 311 published WR chemical analyses, isotopic and mineral chemistry of anorthosites and associated rocks from eight Proterozoic massif anorthosite complexes of India, North America and Norway indicates marked similarities in mineralogy and chemistry among similar rock types. The anorthosite and mafic-leucomafic rocks (e.g., leuconorite, leucogabbro, leucotroctolite, anorthositic gabbro, gabbroic anorthosite, etc.) constituting the major part of the massifs are characterized by higher Na 2 O + K 2 O, Al 2 O 3 , SiO 2 , Mg# and Sr contents, low in plagioclase incompatible elements and REE with positive Eu anomalies. Their δ 18 O (5.7-7.5), initial 87 Sr/ 86 Sr (0.7034-0.7066) and ε Nd values (+1.14 to +5.5) suggest a depleted mantle origin. The Fe-rich dioritic rocks occurring at the margin of massifs have isotopic, chemical and mineral composition more close to anorthosite-mafic-leucomafic rocks. However, there is a gradual decrease in plagioclase content, An content of plagioclase and X Mg of orthopyroxene, and an increase in mafic silicates, oxide minerals content, plagioclase incompatible elements and REE from anorthositemafic-leucomafic rocks to Fe-rich dioritic rocks. The Fe-rich dioritic rocks are interpreted as residual melt from mantle derived high-Al gabbro melt, which produced the anorthosite and mafic-leucomafic rocks. Mineralogically and chemically, the K-rich felsic rocks are distinct from anorthosite-mafic-leucomafic-Fe-rich dioritic suite. They have higher δ 18 O values (6.8-10.8 ) and initial 87 Sr/ 86 Sr (0.7067-0.7104). By contrast, the K-rich felsic suites are products of melting of crustal precursors.

The origin of reddening of granitoid is controversial. Red granitoids, occurring spatially with grey granitoids with a thin transitional zone is a volumetrically significant litho‐type in the Bundelkhand Craton, north central India. Using detailed petrography and microstructure study, and phase compositions and elemental X‐ray maps, we demonstrate for the first time that pervasive infiltration of Fe‐Mg‐Na‐K‐rich fluid caused re‐equilibration of ~2.5 Ga grey monzogranite during both brittle and ductile deformation in the craton. The reddening of granitoid is attributed to replacement and precipitation of tiny Fe‐rich particles in porous feldspars by the high temperature Fe‐Mg‐Na‐K‐rich fluid (~950°C), plausibly from crust–mantle depths. The Fe‐Mg‐Na‐K‐rich fluid with high to moderately high FeO (≤27 wt%), MgO (≤19 wt%), Al2O3 (≤20 wt%), Na2O (<1.59 wt%), K2O (<2.74 wt%), low CaO, (≤0.28 wt%), and FeO/MgO (<1) occurs as discrete interconnected network of green colour veins in the rock. We infer that the veins filled with green‐coloured material along deep shear planes/mylonitic fabric in granitoids and grain boundaries and fractures of felsic minerals (feldspar and quartz) acted as highly permeable network conducive for pervasive fluid activity in the area that influence the normative mineralogy of granitoids yielding pyroxene in the norm. Replacement of original K‐feldspar by plagioclase (albitization), and again by K‐feldspar (K‐feldspathization) by deep fluid took place during which Al2O3 was broadly conserved, with no significant gain or loss in alkalies, a marginal loss in CaO and, but a huge gain in FeO and MgO. The Fe‐Mg‐Na‐K‐rich fluid (with normative olivine + pyroxene) is responsible for near isochemical subsolidus alteration and replacement–precipitation process of feldspars in granitoids. We suggest that the Fe‐Mg‐Na‐K‐rich fluid is of crust–mantle derivation and could intrinsically be linked to Paleoproterozoic dolerite dyke swarm activity in the craton.