English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The study area is located in the Sao Francisco Craton, in the southern part of the State of Bahia, Brazil. In this region, the Palaeoproterozoic Itabuna-Salvador-Curaca Block (ISCB) comprises supracrustal rocks associated with tonalite/trondhjemite and monzonite orthogneisses together with subordinate metamafic rocks of Archean and Palaeoproterozoic ages. All exposed rocks are strongly deformed and were re-equilibrated under granulite facies conditions at 2.07-2.08 Ga. The supracrustal rocks include a sapphirine-bearing granulite that contains sapphirine, quartz, orthopyroxene, sillimanite, garnet, mesoperthite, plagioclase, biotite and cordierite. Based on microstructural relations, the metamorphic peak paragenesis of the sapphirine‑bearing granulite is Grt 1 + Opx 1 + Bt 1 + Qtz + Sil 1 + Spr 1 + Mp. Mineral reaction microstructures, such as symplectitic coronas around porphyroblasts, helped to identify the following retrograde parageneses, interpreted as formed during the tectonic rise of these rocks: Grt 1 ± Qtz = Opx 2 + Sil 2 , Grt 1 = Opx 2 + Spr 2 (+ Sil 2 ), Opx 1 + Sil 1 + Qtz = Crd and Grt 1 + Qtz = Opx 3 + Crd. In turn, Bt 2 + Qtz symplectites formed by the reaction Opx 1-2 + Mp + H 2 O = Bt 2 + Qtz record the retrograde cooling path. Thermobarometry calculations were performed by means of the multiequilibria method (e.g. THERMOCALC) and classic thermobarometeres, which indicated P = 7-11 kbar and T 900 °C for the sapphirine-bearing granulite. One of the mechanisms associated with the ultrahigh-temperature metamorphism is the addition of radioactive material and the presence of basaltic magmas during the formation of ISBC. Fractional crystallization of basaltic magma produced tonalite intrusions, dated approximately 2.15-2.13 Ga, close to the metamorphic peak at 2.07-2.08 Ga.

Metamorfismo de temperatura ultra-alta de granulitos com safirina de 2,0 Ga do Bloco Itabuna-Salvador-Curaçá, Bahia, Brasil