琼东南盆地上中新统—上新统中央峡谷沉积物来源

发布时间：2018-05-03 11:03

本文选题：琼东南盆地 + 上中新统　；参考：《天然气地球科学》2017年10期

【摘要】：应用元素地球化学、重矿物组成及碎屑锆石测年方法,分析了琼东南盆地上中新统—上新统中央峡谷沉积物来源及源区母岩类型。研究表明:中央峡谷稀土元素总量介于168.10×10~(-6)至218.79×10~(-6)之间,平均值为191.01×10~(-6),接近于PAAS而略高于UCC值。轻稀土(LREE)相对富集,La/Yb值较高,介于12.99~15.44之间,平均值为14.41。(La/Yb)N值变化范围为8.76~10.41,平均值为9.72,LREE/HREE值介于3.62~4.24之间,平均值为3.91。铕具有明显的负异常,呈"V"字型,δEu值变化范围为0.53~0.71,平均值为0.6。铈异常不明显,δCe值变化范围为1.03~1.10,平均值为1.06。重稀土(HREE)相对平坦,(Gd/Yb)N值变化范围为1.74~2.01,平均值为1.87,表明母岩为来自上地壳的酸性岩,这一结论与微量元素相关比值(Eu/Eu*、La/Sc、La/Co、Th/Sc以及Cr/Th)以及源区岩性图解Hf—La/Th、La/Sc—Co/Th以及V—Ni—Th×10相一致。对比三大潜在物源区(红河、海南岛及越南中部)沉积物的稀土元素配分模式,发现中央峡谷沉积物稀土元素球粒陨石标准化配分模式与越南中部最为接近;重矿物中锆石、赤褐铁矿以及白钛矿含量高这一特征与越南中部沉积物重矿物特征相吻合;结合前人有关中央峡谷碎屑锆石测年的相关研究,确定中央峡谷沉积物主要来自越南中部的昆嵩隆起带。
[Abstract]:Based on elemental geochemistry, heavy mineral composition and clastic zircon dating, the source and source rock types of the Pliocene Pliocene Central Canyon in the Qiongdongnan Basin were analyzed. The results show that the total amount of rare earth elements in the Central Canyon ranges from 168.10 脳 10 ~ (-6) to 218.79 脳 10 ~ (-6), with an average value of 191.01 脳 10 ~ (-6), which is close to PAAS and slightly higher than the UCC value. The relative enrichment of LREE is relatively high, ranging from 12.99 to 15.44. The average value of LREE is 8.76 ~ 10.41, the average value is 9.72 LREE / hree, and the average value is 3.91.The average value of LREE / HREE is 3.91.The average value of LREE is 8.76 ~ 10.41, and the average value of LREE / hree is between 3.62 ~ 4.24 and 3.91, respectively. Europium has obvious negative anomaly, showing "V" shape, and 未 EU value varies from 0.53 to 0.71, with an average value of 0.6. The ce anomaly is not obvious, and the range of 未 ce value is 1.03 ~ 1.10, with an average value of 1.06. The variation range of Gd / YbN value is 1.74 ~ 2.01 and the average value is 1.87, indicating that the parent rock is acidic rock from the upper crust. This conclusion is consistent with the trace element correlation ratio EU / EU / La / La / La / CoCoP / ThSc and Cr / Thh, and the lithologic diagrams of Hf-La-La-LaSc-CoTh and V-Ni-Th 脳 10. By comparing the REE distribution patterns of sediments from three major potential provenances (Red River, Hainan Island and Central Vietnam), it is found that the standardized distribution model of chondrites in Central Canyon sediments is most close to that in Central Vietnam, and zircon in heavy minerals, The high content of red limonite and white titanite coincides with the characteristics of heavy minerals in the sediments of central Vietnam, and combined with previous studies on zircon dating of the central canyon detritus. It is determined that the sediments of the Central Canyon are mainly from the Kunsong uplift in the central part of Vietnam.
【作者单位】：甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室;中国科学院大学;中海油研究总院;
【基金】：国家科技重大专项(编号:2016ZX05026-007-05)资助
【分类号】：P512.2;P618.13

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