【摘要】 海南岛北部（琼北）巨厚的晚新生代沉积物记录了海南岛晚新生代气候与环境演化信息。但关于该沉积物Sr-Nd同位素方法的物源示踪研究还比较缺乏。以琼北钻遇基岩的钻孔（ZK1-5）为研究对象，以Sr-Nd同位素组成为示踪手段，开展了其物源示踪研究。结果表明：海南岛北部于晚新生代中新世—更新世经历了从滨浅海相沉积—海陆交互相沉积—陆相沉积—火山喷发环境的转变，中新世海相沉积Sr同位素比值（平均值0.727002）整体高于上新世海陆过渡相和更新世陆相沉积的Sr同位素比值（平均值0.714917）,表明海相沉积比海陆过渡相和陆相沉积风化程度更高。海相、海陆过渡相及陆相沉积的Nd同位素组成没有发生明显变化，较一致，表明海陆环境变迁并没有引起该地区物源发生重大变化。而琼北晚新生代沉积物ε_Nd（0）值分布范围（-14.0～-5.1）与岛内花岗质岩石的ε_Nd（0）值分布范围（-14.1～-5.2）基本一致，与岛内变质岩（1.2～8.5）和玄武岩类岩石（1.9～7.8）的ε_Nd（0）值差别较大，表明其源岩主要来自海南岛花岗质岩石，变质岩和玄武岩贡献较小，这可能与岛内花岗质岩石分布范围广有关。对琼北地区晚新生代沉积物Sr-Nd同位素组成特征的认识，有助于深入理解晚新生代海南岛风化过程及环境变化，并对南海物源及古海陆环境重建具有重要意义。更多还原

【Abstract】 The thick Late Cenozoic deposits of northern Hainan Island（Qiongbei）provide a record of paleoclimatic and paleoenvironmental changes in Hainan Island.However, there is a lack of source tracing studies on Sr-Nd isotopic methods in this sediment.In this paper, we carried provenance tracing using a borehole（ZK1-5）drilling encounter with bedrock in northern Hainan Island by Sr-Nd isotopic method.The results show that the Late Cenozoic of northern Hainan Island underwent a transition from coastal shallow marine sedimentation-marine and continental alternative deposition-terrestrial sedimentation-volcanic eruption environment from the Miocene to the Pleistocene, and that the Sr isotopic ratio of the Miocene marine sediment（mean: 0.727002）is overall higher than that of the Pliocene marine and terrestrial transition and Pleistocene terrestrial deposits（mean: 0.714917）,suggesting that marine deposits were more weathered than the marine and terrestrial transitional phases.The Nd isotopic compositions of the marine, marine-terrestrial transitional and terrestrial deposits do not change significantly and are relatively consistent, suggesting that provenance did not change obviously caused by environmental changes from marine to terrestrial in the area.The distribution of ε_Nd（0）values in the Late Cenozoic sediments of Qiongbei（-14.0～-5.1）is generally consistent with the distribution of ε_Nd（0）values in the granitic rocks of Hainan Island（-14.1～-5.2）,and differs considerably from the ε_Nd（0）values in the metamorphic rocks（1.2～8.5）and basaltic rocks（1.9～7.8）of Hainan Island, indicating that the source rocks are mainly from the local granitic rocks in Hainan Island, and the contribution of metamorphic rocks and basalt is small.This is probably related to the wide distribution of granitic rocks in the island.The understanding of the Sr-Nd isotopic characteristics of the Late Cenozoic sediments in the northern Hainan Island can help to deeply understand the weathering process and environmental changes on Hainan Island during the Late Cenozoic, and is of great significance for the reconstruction of the provenance and sea and land environment change in the northern South China Sea.更多还原