R8: Metamorphic rocks and tectonics

[R8P-09] Metamorphic history of corundum-bearing high-pressure amphibolite from the Paleoproterozoic Usagaran Belt, Tanzania

*Rio Higuchi¹, Tatsuki Tsujimori², Nelson Boniface³ (1. Dept. Earth Sci., Tohoku Univ., 2. CNEAS, Tohoku Univ., 3. UDSM)

Keywords:Usagaran Belt, Tanzania, continental collision, high-pressure amphibolite, granulitization

Corundum-bearing amphibolite occurs in a meta-cumulate body of the Paleoproterozoic Usagaran Belt, SE Tanzania. The studied rock has a compositional banding of amphibolitic and garnetititic layers; corundum occurs in both layers. Petrological studies of the rock revealed a decompression P–T trajectory that is characterized by corrosion of primally corundum at the rims by Mg–Al spinel. The replacement textures might suggest a partial granulitization of high-pressure amphibolite. This process might occur during the crustal stabilization after collisional event.