Geology and petrography of Jauru Group, at region of Retiro Novo Farm, SW of Amazonian Craton: a Statherian accretionary prism evidence

作者：Pereira Santos Flavia Regina; da Silva Carlos Humberto; Dantas da Costa Ana Claudia; de Siqueira Neto Antonio Carlos

来源：Brazilian Journal of Geology, 2016, 46(1): 129-146.

DOI：10.1590/2317-4889201600030309

• Alto Jauru Group
• Amazonian Craton
• geocronology U-Pb
• accretionary prism

The Alto Jauru Group, located in southwestern Amazonian Craton, region of Retiro Novo Farm, comprises biotite-muscovite-quartz schists, chlorite-biotite-muscovite schists, garnet-cordierite-biotite schist and staurolite-andalusite-biotite schist, associated with garnet-sillimanite-biotite gneiss, biotite gneiss, amphibolite and muscovite granite. The group shows evidence of being an accretionary prism dominated by sediments. Petrography and structural relationships indicate that it was affected by two deformational events, D-n and Dn+1, associated with Sn foliation (schistosity and gneissic banding) and Sn+1 (crenulation cleavage), and three metamorphic events (M1, M2 and M3): the first is contemporary with S-n in lower greenschist facies; M2 is associated with the second phase of Sn+1 under greenschist to amphibolite facies; the third thermal event of amphibolite facies resulted from intrusion of the Cabacal tonalite. Determination obtained by U-Pb (SHRIMP) on zircon provided the age of 1819 +/- 6.7 Ma for the crystallization biotite gneiss igneous protolith. From the tectonic point of view, the Alto Jauru Group corresponds to an accretionary prism formed in the Statherian.

• 出版日期2016-3