(Table 1) 40Ar/39Ar plateau and isochron ages for basalts from the Réunion hotspot track

Concordant plateau and isochron ages were calculated from 40Ar/39Ar incremental heating experiments on volcanic rocks recovered by drilling at four Leg 115 sites and two industry wells along the volcanic lineament connecting Reunion Island to the Deccan flood basalts, western Indian Ocean. The new ages provide unequivocal evidence that volcanic activity migrated southward along this sequence of linear ridges. The geometry and age distribution of volcanism are most compatible with origin above a stationary hotspot centered beneath Reunion. The hotspot became active with rapid eruption of the Deccan flood basalts, western India, and subsequent volcanic products record the northward motion of the Indian and African plates over the hotspot through Tertiary time. The radiometric ages are in general accord with basal biostratigraphic age estimates, although some adjustments in current magnetobiostratigraphic time scales may be required.对沿连接留尼旺岛（Reunion Island）与西印度洋德干洪流玄武岩的火山构造线，在大洋钻探计划第115航次的4个站位以及2口工业钻井中钻探获取的火山岩开展40Ar/39Ar逐步加热实验，计算得到了一致的坪年龄与等时年龄。本次新获得的年龄数据为火山活动沿该线性脊系向南迁移提供了明确证据。火山作用的几何形态与年龄分布，与以留尼旺岛下方为中心的静止热点成因最为匹配。该热点随印度西部德干洪流玄武岩的快速喷发而进入活动阶段，后续的火山产物记录了第三纪时期印度板块与非洲板块在该热点上方的北向运动过程。尽管当前的磁生物地层年代标尺或需做出部分调整，但本次放射性同位素年龄结果总体与基底生物地层年龄估算值相符。