[SMP39-P08] Whole-rock chemical composition of the granitoids in Ryoke belt, Takanawa Peninsula, northwest Shikoku, southwest Japan
Keywords:Granitoids in Ryoke belt, Whole-rock chemical composition , Sr-Nd isotope, Takanawa Peninsura
We carried out whole-rock and Sr-Nd isotope analysis of the Ryoke granitoids exposed in the Takanawa Peninsula to indicate their petrological characteristic. Takanawa Peninsula located in northwest Shikoku island, southwest Japan. Multiple granitoids are distributed on the Takanawa Peninsula. The granitoids are mainly comprised of tonalitic rocks, granodioritic rocks, and granitic rocks. These show different SiO2 content : 61-68 wt% for tonalitic rocks, 67-76 wt% for granodioritic rocks, 70-80 wt% for granitic rocks. And these show multiple trends on Harker diagram. Sr-Nd isotope composition of granitoids shows equivalent contents between SrI: 0.70669-0.70793 and NdI: 0.51217-0.51234. The multiple trends on Harker diagram suggest this area’s granitoids were comprised multiple magma. Similar SrI and NdI contents in granitoids suggest the same source of granitoids. Kagami et al. (1985; 2000) and Kodama et al. (2019) showed mafic rocks around this area had similar SrI (0.70654-0.70657) and NdI (0.51173-0.51241) composition to granitoids. Our results suggest that mafic rocks are a source material of granitoids in Takanawa Peninsula.
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