珠江口盆地白云凹陷超深水区层序-沉积及古环境特征:以A1井为例  

Sequence sedimentary and paleoenvironmental characteristics in ultra-deep water area of Baiyun Sag,Pearl River Mouth Basin:taking Well A1 as an example

作　　者：卫哲 曾驿 周小康 易浩 时翠 WEI Zhe;ZENG Yi;ZHOU Xiaokang;YI Hao;SHI Cui(Shenzhen Branch of CNOOC(China)Co.,Ltd.,Shenzhen 518064,Guangdong,China;CNOOC Deepwater Development Ltd.,Shenzhen 518064,Guangdong,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518067 [2]中海石油深海开发有限公司,广东深圳518067

出　　处：《世界地质》2024年第1期47-55,共9页World Geology

基　　金：中国海洋石油有限公司“十四五”重大科技项目(KJGG2022-010)。

摘　　要：为系统认识珠江口盆地白云凹陷超深水区层序界面识别和沉积环境演变,笔者采用白云凹陷已钻A1井晚渐新统珠海组—早中新统珠江组碳酸盐岩层段微量元素和常量元素数据开展综合分析,研究表明:①通过Pb、Zn、Rb、Al_(2)O_(3)、Fe_(2)O_(3)、Th/U比值等参数的变化特征识别了SB24.80、SB23.03和SB21.00共3个三级层序界面;②利用Sr/Ba、V/Ni、Sr/Cu、Al_(2)O_(3)/MgO、MgO/CaO比值的变化证实样品段以干热气候、海平面相对上升的沉积环境为主;③通过V/Cr、Ni/Co、V/(V+Ni)等比值表明,A1井碳酸盐岩主要发育在氧化环境的古海洋水体中,水体较浅,晚期水位上升趋向于贫氧环境,直至“淹死”终止碳酸盐岩发育。To systematically understand the sequence boundary identification and sedimentary environment evolution in the ultra-deep water area of the Baiyun Sag,Pearl River Mouth Basin,the authors conducted a comprehensive analysis using trace and major element data from the carbonate rock section of the Late Oligocene Zhuhai Formation to Early Miocene Zhujiang Formation of the drilled Well A1 in Baiyun Sag.The results show:①Three third-order sequence boundaries of SB24.80,SB23.03 and SB21.00 were identified through the variation characteristics of parameters such as concentrations of Pb,Zn,Rb,Al_(2)O_(3),Fe_(2)O_(3),and Th/U ratio.②Based on the variability of Sr/Ba,V/Ni,Sr/Cu,Al_(2)O_(3)、/MgO,and MgO/CaO ratios,it is confirmed that the sample section deposited mainly in a sedimentary environment characterized by arid climate and relative sea-level rise.③Ratios of V/Cr,Ni/Co,V/(V+Ni)suggest that the carbonate rocks in Well A1 are mainly developed in ancient marine water bodies of oxidizing environments,with shallow water bodies.In the later stage,the water level tended to rise towards hypoxic conditions,and the development of carbonate rocks was terminated by“drowning”.

关 键 词：地球化学元素 层序界面 古环境 白云凹陷 珠江口盆地 

分 类 号：P618.13[天文地球—矿床学]