1. 琉球弧火山前緣的火山岩(SiO
2< wt.57%)與全球大部分島弧火山岩有相似的特徵：
(1) 鋰濃度(4.61 ~ 13.3 ppm)與 Li/Y(0.21 ~ 0.72)皆高於普通中洋脊玄武岩(N-MORB)。
(2) 𝛿7Li 為-2.44 到+12.49，大部分落在普通中洋脊玄武岩(N-MORB)範圍內，
且其變化與流體指標無關(e.g. Li/Y, Pb/Ce, and Ba/Th)。
2. 琉球弧火山前緣的火山岩中，九州南部𝛿
7Li 為-2.44 到+2.86 較琉球北部與琉球中部𝛿7Li 為+3.49 到+9.40 更低，這與隱沒沉積物還有隱沒板塊表層的溫度有關：
九州南部與琉球北部的隱沒沉積物—四萬十頁岩提供岩漿源低𝛿7Li 的流體，同時
九州南部是琉球弧中隱沒板塊表層最低溫的區段，這些低𝛿7Li 流體才能影響島弧
岩漿源區。
3. 在琉球北部的火山岩中可以觀察到在島弧的橫向上，其鋰同位素系統與流體有
關，離海溝越遠的樣本MKR-2，流體訊號越弱，其 Li/Y 會降低，且𝛿7Li 會降低。4. 本研究證實在隱沒帶中流體仍是影響島弧火山岩鋰同位素變化的主因，而影響
進入岩漿源流體的因子有下列兩者：(1) 隱沒物質的𝛿7Li。
(2) 隱沒板塊表層的溫度。
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