Geotectonic evolution of the 2.47 Ga to 2.28 Ga Almas-Conceição do Tocantins Domain in Central Brazil, using isotopic (Sm-Nd) and whole-rock geochemical data

Based on Sm-Nd isotope and whole-rock geochemical data, we aim to understand the geotectonic evolution of the plutonic rocks (2.47-2.28 Ga) exposed in the Almas-Conceição do Tocantins Domain (ACTD). The studied rocks belong to a Siderian association (ca. 2.47-2.3 Ga) and to Early Rhyacian units (ca. 2.29-2.28 Ga). The Siderian association rocks were grouped into: (1) TTG suites of the Ribeirão das Areias Complex-RAC and the Ribeirão Itaboca Suite-RIS [ ε Nd(t) =+1.9 to +1.2, SiO 2 =64-71 wt%, Na 2 O=4-5.6 wt%, K 2 O=0.4-1.4 wt%, K 2 O/Na 2 O=0.1-0.2, Th=0.6-2.1 ppm]. (2) Transitional TTG rocks-T-TTG [ ε Nd(t) =+2.3, SiO 2 =63-75 wt%, Na 2 O=3-4 wt%, K 2 O=2.9-3.6 wt%, K 2 O/Na 2 O=0.8-0.9, Th=2.2-6.7 ppm]. The Early Rhyacian units are represented by: (3) Pau Ramalhudo Suite-PRS (2.29 Ga) high-K biotite granites [SiO 2 =74-76 wt%, K 2 O=4.2-4.6 wt%, K 2 O/Na 2 O=1.1 wt%]. (4) Diorite Association (2.28 Ga) sanukitoids [ ε Nd(t) =+0.9 to +2.0, SiO 2 =59 wt%, K 2 O=1.4-1.8 wt%, MgO=2.5-2.8 wt%, Ba+Sr=1346-1536 ppm]. The obtained and compiled dataset shows that the Almas-Conceição do Tocantins records the secular evolution of the composition of granitoids at the Siderian-Rhyacian boundary. This evolution involves the transition from an initial juvenile phase of TTG formation to the recycling of older crustal material and the diversity of the magmatism. In this late geotectonic context, the sanukitoid intrusion is interpreted to represent a juvenile addition.