Mineral chemistry and magnetic petrology of the Archean Planalto Suite, Carajás Province – Amazonian Craton: Implications for the evolution of ferroan Archean granites

Mineral chemistry and crystallization parameters of the A-type Paleoproterozoic Bannach Granite, Carajás Province, Pará, Brazil

“…In a similar way, experiments carried out at 300 MPa and oxidizing conditions in the Jamon Granite showed that a minimum content of ~4.5 up to ~6.5 wt.% of water was necessary to assure magnetite + hornblende + plagioclase stability during its initial crystallization stage (Dall'Agnol et al 1999c). Cunha et al (2016), based on the stability of amphibole, estimated a minimum content of 4 wt.% of water in the Planalto Granite magma. Thus, by analogy with Jamon Granite, a magma water content between 4.5 and 6.5 wt.% can also be considered for Bannach Granite, once mineral association, crystallization history, and emplacement pressure are similar in both granites.…”

“…conditions (Anderson & Smith 1995, Anderson et al 2008, Dall'Agnol et al 2005, Cunha et al 2016. Almeida et al (2006) had highlighted that the LmLMz facies differs from other Bannach facies, not only in field occurrence but also in the geochemical behavior of Y and rare earth elements (REE).…”

“…Zircon saturation (Watson & Harrison 1983, Miller et al 2003 and amphibole-plagioclase (Blundy & Holland 1990) geothermometers have also been used to determine crystallization temperatures in many igneous rocks. Recent works are estimating or discussing crystallization parameters based on the chemical composition of the main mineral phases in granitoids rocks (Ridolfi et al 2010, Ridolfi & Rezulli 2012, Erdmann et al 2014, Cunha et al 2016, Putirka 2016, Mutch et al 2016, for specific evaluations of the Al-in-hornblende geobarometer). The oxygen fugacity that dominates during the magmatic evolution can be estimated using Fe/(Fe + Mg) ratios in amphibole and biotite, given this ratio is strongly dependent of oxygen fugacity (Anderson & Smith 1995, Dall'Agnol et al 1999b, 1999c, 2005, 2017, Anderson & Morrison 2005, Dall'Agnol & Oliveira 2007, Anderson et al 2008, Cunha et al 2016.…”

“…Recent works are estimating or discussing crystallization parameters based on the chemical composition of the main mineral phases in granitoids rocks (Ridolfi et al 2010, Ridolfi & Rezulli 2012, Erdmann et al 2014, Cunha et al 2016, Putirka 2016, Mutch et al 2016, for specific evaluations of the Al-in-hornblende geobarometer). The oxygen fugacity that dominates during the magmatic evolution can be estimated using Fe/(Fe + Mg) ratios in amphibole and biotite, given this ratio is strongly dependent of oxygen fugacity (Anderson & Smith 1995, Dall'Agnol et al 1999b, 1999c, 2005, 2017, Anderson & Morrison 2005, Dall'Agnol & Oliveira 2007, Anderson et al 2008, Cunha et al 2016. The composition of primary magnetite-ilmenite pairs and the nature of Fe-Ti oxide minerals formed during the magmatic stage are also useful to establish constraints about the oxygen fugacity prevalent in crystallization (Ishihara 1981, Wones 1989, Frost & Lindsley 1991, Frost 1991, Clark 1999, Dall'Agnol et al 1997, 1999b, 2005, Dall'Agnol & Oliveira 2007.…”

Granitoides TTG de Água Azul do Norte (PA): implicações tectônicas para a Província Carajás

“…Esses subdomínios são limitados por grandes descontinuidades regionais de direção E-W e apresentam significativas diferenças em sua evolução geológica, reconhecidas a partir das associações litológicas presentes nesses blocos. O SDCC é caracterizado pela dominância de granitos stricto sensu e associações charnoquíticas neoarqueanas, com raras ocorrências de TTG e granitos anorogênicos (Feio et al, 2012(Feio et al, , 2013Dall'Agnol et al, 2013;Rodrigues et al, 2014;Cunha et al, 2016), enquanto o SDS é formado por granitoides do tipo TTG, sanukitoides e leucogranitos diversos, análogos àqueles identificados no DRM, sendo, porém, afetados por eventos neoarqueanos (Santos et al, 2013a;Santos et al, 2013b;Teixeira et al, 2013;Gabriel e Oliveira, 2014, Silva et al, 2014Leite-Santos e Oliveira, 2014, 2016. Contudo, ainda não há conhecimento detalhado sobre a crosta TTG que aflora no SDS, especificamente na região de Água Azul do Norte, uma vez que nos trabalhos ali realizados tal variedade foi alvo apenas de estudos petrográficos e geoquímicos preliminares, impossibilitando que se conhecesse a It exhibits moderate to high La/Yb and Sr/Y ratios, and low Nb/Ta ratio, which indicates that they wereit was produced from partial melt of metamafic source, at high to intermediate pressure conditions (~1.0-1.5 GPa), but still in the garnet stability field.…”