Rio Maria granodiorite and associated rocks of Ourilândia do Norte – Carajás province: Petrography, geochemistry and implications for sanukitoid petrogenesis

Magmatic epidote in Archean granitoids of the Carajás Province, Amazonian craton, and its stability during magma rise and emplacement

“…Geochemically, sanukitoids and associated rocks exhibit a highly variable SiO 2 content, moderate K 2 O values and high Mg#, Cr and Ni values. They have a predominantly metaluminous character and a calc-alkaline to high-K calc-alkaline signature (Santos and Oliveira, 2016;Silva et al, 2018). Two textural types of magmatic epidote were distinguished: crystals with zoned or unzoned allanite cores and euhedral to subhedral crystals J o u r n a l P r e -p r o o f associated with biotite and hornblende, partly surrounded by them (Santos and Oliveira, 2016).…”

“…The Ourilândia do Norte area is located near the borders of the Rio Maria, Canaã dos Carajás and Sapucaia domains in the CP. This area is marked by a diverse Mesoarchean magmatism, mainly characterized by leucogranites, sanukitoids and associated rocks (Santos and Oliveira, 2016;Silva et al 2018). The Mesoarchean sanukitoids of the Ourilândia do Norte region are identified as a composite body, predominantly consisting of granodiorites and equigranular tonalites, with subordinate quartz diorite and quartz monzodiorite, which form elongated and deformed lenses along the E-W direction.…”

“…2b). The sanukitoids of Ourilândia do Norte (Santos and Oliveira, 2016) have a high amphibole content, and epidote is a significant accessory mineral (ranging from trace to 3.9% and reaching 6.2% in the epidote-biotite-amphibole diorite variety). Mafic aggregates consisting of hornblende ± actinolite, biotite, epidote, titanite and Fe-Ti oxides are common.…”

“…Dall'Agnol et al (2017) proposed that the magmas that formed the VJS were generated under pressures between 800 and 1000 MPa, and emplacement pressures were estimated to range from 300 to 500 MPa based on Al-inamphibole geobarometer and geological evidence; a value of 400 MPa is assumed here as the emplacement pressure of these granitoids. The Ourilândia do Norte sanukitoids exhibit ductile structures and evidence of penetrative deformation associated with mylonitic structures (Santos and Oliveira, 2016;Silva et al, 2018;Nascimento, 2020). Nascimento (2020), based on Al-in-hornblende geothermometer measurements, estimated an emplacement pressure of ~200 MPa for those sanukitoids.…”

“…The present study focuses on three different types of granitoids that occur in the Sapucaia Domain of this province and at its border with the Rio Maria Domain. Such granitoid rocks include tonalites and trondhjemites of TTG associations (Santos et al, 2013;Teixeira et al, 2013;Silva et al, 2014;Leite-Santos and Oliveira, 2014) and sanukitoids Santos and Oliveira, 2016;Silva et al, 2018), both of Mesoarchean age (2.93 a 2.85 Ga), as well as ferroan to magnesian Neoarchean granitoids (~2.75 to 2.73 Ga), geochemically akin to A-type granites (Dall'Agnol et al, 2017;Silva et al, 2020).…”