【摘要】 讨论了100 Ma以来海水锶同位素比值的变化趋势及控制因素。100~40 Ma期间,海水锶同位素比值有多次升降,总体上变化幅度较小;40 Ma以来,海水锶同位素比值显著增加,并呈现出单调上升的总体特征。100 Ma以来海水锶同位素的变化主要可能与星外物体对地球的撞击作用;全球海平面变化及洋中脊扩张速度的改变;喜马拉雅—青藏高原的隆升;玄武岩喷发和冰川作用因素有关。在各种因素中,喜马拉雅—青藏高原的隆升对40 Ma以来海水锶同位素演化具有最重要的控制作用。喜马拉雅—青藏高原的隆升可能始于40 Ma左右,隆升速度最快的时期在20~15 Ma。更多还原

【Abstract】 The Sr-isotope composition and evolvement in sea water since 100Ma and the controlling factors are discussed.The sea water ⁸⁷Sr/⁸⁶Sr ratios in the period of 40¹00Ma have some fluctuations with smaller extent.The sea water ⁸⁷Sr/⁸⁶Sr ratios have increased rapidly and monotonously since 40 million years.The following factors controlled the Sr-isotope composition and evolvement in sea water since 100Ma: the possible impact of extraterrestrial object;the global sea-level change and the spread rate of the mid-oceanic ridge;the uplift of Himalaya-Tibet;the eruption of major continental flood basalts and glaciations.Among of above factors,the uplift of Himalaya-Tibet plays an important role in the evolution of seawater ⁸⁷Sr/⁸⁶Sr ratios for the last 40Ma.The starting time for the Himalayan-Tibet uplift should be at 40Ma BP,and the most rapid period of the uplift took place during 20¹5Ma.更多还原