珠江口及北部湾盆地泥岩地球化学特点

通过地球化学研究表明，珠江口及北部湾盆地泥岩中稀土元素分布配分形式显示轻稀土元素较平稳，铕出现明显亏损的特点，与澳大利亚后太古代页岩（ＰＡＡＳ）的分布特点相似，但样品的稀土元素（ＲＥＥ）高于ＰＡＡＳ。在Ｔｈ－Ｈｆ－Ｃｏ三角图解中，所有样品均位于上地壳平均值的上方，远离地壳平均值和洋壳，说明珠江口、北部湾盆地沉积物母岩以来自上地壳偏酸性的岩石类型为主，地球化学判别分析结果表明珠江口盆地与北部湾盆地在

Geochemical Characteristic of Mudstone and Provenance Analyses of the Pearl Basin and Beibu - Gulf Basin

The REE distributions of the mudstone from the Pearl and Beibu-Gulf Basins show LREE enrichment, have a flat HREE pattern and a negative Eu-anomaly. In comparison with the PAAS, the REE distribution patterns of the samples are generally like it, but the contents of REE elements in the mudstone are high. On the Th-Hf-Co triangle diagram, all samples appear to be close to the upper crustal composition, away from the average continental crust and oceanic crustal one. Accordingly, the material of the source rocks for the samples of the basin are felsic rock type and most probably derived from the upper continental crust. The provenance is much different between the Pearl Basin and Beibu-Gulf Basin based on discriminant analyses of geochemical data. The source rocks of the Pearl Basin are mainly of metamorphic rocks and granite, while the carbonate and clastic sedimentary rocks are the most source rock types in the Beibu-Gulf Basin. In the Pearl Basin, the incorrectly classified rate of samples between Zhu 1 Sag and Zhu 3 Sag is nearly 30%, indicating there are some same source rock areas between them.