Ferroan granites (585–530 Ma) have been described in the Transversal subprovince of the Borborema Province (BP) and in Pan-African counterparts. They comprise two groups: Group 1 – slightly peraluminous to metaluminous, alkali-calcic rocks, with low Fe# mica and crystallized under intermediate fO₂ (Aroeiras Complex and Serra Branca – Coxixola dike swarms); Group 2 metaluminous to slightly peraluminous, alkalic to alkali-calcic rocks, with high Fe# mica and crystallized under low fO₂ (Queimadas and Prata intrusions). Group 1 marks transition from collision to transcurrence (ca. 585 Ma), or from transcurrence to uplift and transtension (ca. 545 Ma). Group 2 – represents granitoids intruded during extensional tectonics in transcurrent setting (ca. 550 Ma), or coeval with deposition of transtensional intracratonic basins (ca. 530 Ma). Hf and Nd model ages are older than 2.0 Ga, suggesting that the ferroan granitoids involved partial melting of Paleoproterozoic rocks. The data presented in this paper show that the ferroan magmatism was widespread in the BP and its counterparts in Africa in pre-drift reconstructions.

Ediacaran–Cambrian magmatism in the Central Subprovince (Borborema Province, NE Brazil) generated abundant A-type granites. This study reviews published whole-rock and mineral chemistry data from thirteen Ediacaran–Cambrian A-type intrusions and a related dike swarm. It also presents new mineral chemistry and whole-rock data for one of these intrusions, along with zircon trace element data for five of the intrusions. Geochronological data from the literature indicate the formation of these A-type intrusions during a 55 Myr interval (580–525 Ma), succeeding the post-collisional high-K magmatism in the region at c. 590–580 Ma. The studied plutons intruded Paleoproterozoic basement gneisses or Neoproterozoic supracrustal rocks. They are ferroan, metaluminous to peraluminous and mostly alkalic–calcic. The crystallization parameters show pressure estimates mainly from 4 to 7 kbar, corresponding to crustal depths of 12 to 21 km, and temperatures ranging from 1160 to 650 °C in granitoids containing mafic enclaves, and from 990 to 680 °C in those lacking or containing only rare mafic enclaves. The presence of Fe-rich mineral assemblages including ilmenite indicates that the A-type granites crystallized under low ƒO₂ conditions. Zircon trace element analyses suggest post-magmatic hydrothermal processes, interpreted to be associated with shear zone reactivation. Whole-rock geochemical characteristics, the chemistry of the Fe-rich mafic mineral assemblages, and zircon trace elements in the studied granitoids share important similarities with A₂-type granites worldwide.

Ferroan granites (585-530 Ma) in the Transversal subprovince of the Borborema Province (BP) comprise two groups: G1) slightly peraluminous to metaluminous, alkali-calcic rocks (Aroeiras Complex and Serra Branca - Coxixola dike swarms (SBCDS)); G2) metaluminous to slightly peraluminous, alkalic to alkali-calcic rocks (Queimadas and Prata intrusions). G1 are transitional from collision to transcurrence (ca. 585 Ma), or transcurrence to transtension (ca. 545 Ma). G2 represents the granitoids intruded during post-collisional crustal thinning (ca. 550 Ma), or coeval with deposition of intracratonic basins (ca. 530 Ma). The large-ion lithophile elements (LILE) and high field strength elements (HFSE) enriched geochemical signature of these granitoids are recognizable in gamma spectrometric maps of regional scale, highest values of K(%), eTh(ppm), and eU(ppm) contrast significantly with country rocks and magnesian granites. This study shows that gamma-ray spectrometric regional maps reflect the geochemical characteristics of the ferroan intrusions. Moreover, in the local maps for each intrusion, it is possible to identify internal heterogeneities in these plutons, which correlate to geological processes, geochemistry, and petrography. Diorites and gabbros show low to medium values of K (1-3%), eTh (5-20 ppm) and eU (0.2-2 ppm), contrasting with the high values of regions with a dominance of ferroan granitoids (K, 3-6%; eTh, 15-60 ppm; eU, 2-4 ppm).