【作者】 余烨； 张昌民； 张尚锋； 施和生； 杜家元；

【Author】 YU-Ye~(1,2) ZHANG Chang-ming~(1,2) ZHANG Shang-feng~(1,2) SHI He-sheng~3 DU Jia-yuan~(1,2,3) (1.School of Geosciences,Yangtze University,Jingzhou,Hubei 434023,China;2.MOE Key Laboratory of Oil and Gas Resource and Exploration Technology,Yangtze University,Jingzhou,Hubei 434023,China; 3.Shenzhen Branch of CNOOC Ltd.,Guangzhou,Guangdong 510240,China)

【机构】 长江大学地球科学学院； 长江大学油气资源与勘探技术教育部重点实验室； 中海石油(中国)有限公司深圳分公司；

【摘要】 通过对珠江口盆地惠州凹陷珠江组碎屑岩的主量元素、微量元素和稀土元素进行综合分析,发现研究区碎屑岩的MnO、Na₂O、P₂O₅和TiO₂与PAAS有相同的含量,富集SiO₂,贫Al₂O₃、Fe₂O₃、K₂O和MgO。亲石元素Ba略低于上地壳丰度,而远高于下地壳;过渡元素Cr略高于上地壳丰度,而远低于下地壳;不相容元素Th较高于上地壳丰度值,远远高于下地壳。REE分布模式与上地壳相似,轻稀土元素富集,重稀土元素均一,Eu负异常,微量元素比值显示源岩以长英质岩石为主。从SiO₂—K₂O/Na₂O、La-Th-Sc判别图及Ce异常值的分析认为,源区的构造背景属被动大陆边缘环境。据锶钙比值1000×（Sr/Ca）和V/OCr值分析,珠江组从下往上水体有逐渐加深的趋势,与单井沉积相分析结果一致。据镁铝比值100×（MgO/Al₂O₃）和Sr/Ba值分析,珠江组从下往上沉积环境的水体盐度变化不是很大,但到上部略有下降。古气候指示剂Rb/Sr值和MgO/CaO值显示,NSQ1和NSQ2层序时期气候干燥寒冷,而NSQ3和NSQ4这两个层序时期气候湿热。更多还原

【Abstract】 Through a comprehensive analysis on the major elements,trace elements and rare earth elements of clastic rock of the Zhujiang formation in the Huizhou Depression,Pearl River Mouth Basin,this paper found that the clastic rock of study area has the same contents of MnO,Na₂O,P₂O₅ and TiO₂ as that in PAAS.It is enriched in SiO₂ and poored in Al₂O₃,Fe₂O₃,K₂O and MgO.The content of Ba is lower than the supracrustal abundance,but it is far higher than crustal abundance.The content of Cr is higher than the supracrustal abundance,but it is far lower than crustal abundance.The content of Th is higher than the supracrustal abundance,and it is far greater than crustal abundance.The REE distribution pattern is similar to that of the upper continental crust,characterized by enrichment of LREE,uniform of HREE and negative Eu anomalies.Some trace element ratios show that the source rocks are mainly felsic.According to SiO₂-K₂O/Na₂O,La-Th-Sc discrimination diagrams and Ce anomalies,the tectonic setting of the provenance is similar to that of passive continental margin.The analytic result of the value of 1000×Sr/Ca and V/Cr revealed that the depth of sedimentary water increased from bottom to top in the Zhujiang formation,and the variation law is consistent with the conclusions of sedimentary facies.The analytic result of the value of 100×MgO/Al₂O₃ and V/Cr revealed that the salinity is steady from bottom to top in in the Zhujiang formation,but it is slightly down in the top of the Zhujiang formation.Based on the characters of Rb/Sr and MgO/CaO,NSQ1 and NSQ2 are deposited in cool-dry climate condition,NSQ3 and NSQ4 are deposited in warm-wet climate condition.更多还原