摘要
塔里木盆地寒武系白云岩是油气勘探的重要领域,由于钻孔取芯较少,且大量白云岩化造成生物化石难以识别与鉴定,导致寒武纪地层的划分与对比问题长期以来存在多解性。通过研究塔里木盆地钻孔苗岭统-芙蓉统开展碳同位素地层学,拟解决寒武系苗岭统的等时对比问题。分析结果显示不同钻孔相同层位同位素漂移表现出一致性特征,塔西台地区沙依里克组底部出现明显的碳同位素负漂移(N1),阿瓦塔格组顶部出现碳同位素负漂移(N2),下丘里塔格组下部见碳同位素负漂移(N3)、中部出现碳同位素正漂移(P1);塔东盆地区突尔沙克塔格组下部出现碳同位素正漂移(P1’),莫合尔山组底部(N1’)、中部(N2’)、上部(N3’)各见一个碳同位素微弱负漂移。在古生物地层框架下,通过与全球对比分析,提出:1)塔西台地区沙依里克组底部碳同位素负漂移N1与全球性Redlichiid-Olenellid Extinction Carbon isotope Excursion(ROECE)可对比, N1底对应寒武系苗岭统底;推测塔东盆地区莫合尔山组底微弱负漂移N1’底对应苗岭统底。2)下丘里塔格组中部、突尔沙克塔格群下部出现的碳同位素正漂移(P1;P1’)与全球性Steptoean Positive Carbon Isotope Excursion (SPICE)可对比, P1与P1’底对应芙蓉统排碧阶。3)塔西台地区苗岭统阿瓦塔格组底部碳同位素负漂移N2、塔东盆地区莫合尔山组中部负漂移N2’可能等时对应Drumian Carbon Isotope Excursion (DICE),代表鼓山阶/乌溜阶的接触界限;塔西台地区下丘里塔格组下部的碳同位素负漂移N3、塔东盆地区莫合尔山组上部的同位素负漂移N3’可能对应古丈阶/鼓山阶界线。
Cambrian subsalt dolostones have been considered as one of the most important exploration development for oil and gas in Tarim basin. However, subdivision and correlation of the Cambrian strata in Tarim basin remains uncertain since long time ago because of the absence of fossils and few of drill hole materials. In this paper, carbon isotope stratigraphic method is applied on studying drill holes. Results show that the carbon isotope excursions are consistent in different drill holes. Obvious negative excursions occur at the bottom of Shayilike Formation(N1), top of Awatage Formation(N2), lower part of Xiaqiulitage Formation(N3), and a remarkable carbon isotope positive excursion occurs at the middle of Xiaqiulitage Formation(P1) in western Tarim basin. In the eastern Tarim basin, an obvious carbon isotope positive excursion occurs at the lower part of Tuershaketage Formation(P1’), and three minor negative excursions occur at bottom, middle and upper of Moheershan Formation(N1’, N2’ and N3’) respectively. Based on global correlation, it is concluded that: 1) In western Tarim basin, N1 at the bottom of Shayilike Formation is correlative to the global Redlichiid-Olenellid Extinction Carbon isotope Excursion(ROECE) at the base of the Miaolingian. In eastern Tarim Basin, N1’ at the bottom of Moheershan Formation represents the ROECE at the basal Miaolingian. 2) P1 at middle of Xiaqiulitage Formation in western Tarim basin and P1’ at lower of Tuershaketage Formation in eastern Tarim basin can be correlated to the global Steptoean Positive Carbon Isotope Excursion(SPICE), which represents the Paibian Stage(Furongian). 3) N2 at the top of Awatage Formation in western Tarim Platform and N2’at the lower part of Moheershan Formation is correlatable to the Drumian Carbon Isotope Excursion(DICE), corresponding to the base of the Drumian Stage, while N3 at the lower part of Xiaqiulitage Formation in western Tarim Platform and N3’ at the upper part of Moheershan Formation is correlatable to the boundary of Guzhangian/Drumian stages.
作者
陈永权
张艳秋
周鹏
阿里木·卡德尔
CHEN Yong-quan;ZHANG Yan-qiu;ZHOU Peng;KADERER Alimu(PetroChina Tarim Oil Field Company, Korla 841000)
出处
《地层学杂志》
CSCD
北大核心
2019年第3期324-332,共9页
Journal of Stratigraphy
基金
国家科技重大专项课题(2016ZX05004-004
2017ZX05008-005)资助
关键词
塔里木盆地
寒武系
苗岭统
碳同位素地层
Tarim Basin
Cambrian
Miaolingian
carbon isotope stratigraphy
