石油学报 ›› 2012, Vol. 33 ›› Issue (1): 40-47.DOI: 10.7623/syxb201201005

• 地质勘探 • 上一篇    下一篇

歧口凹陷古近系沙河街组一段下亚段湖盆咸化成因

陈世悦 1 王 玲 1 李 聪 2 蒲秀刚 3 孙廷彬 1   

  1. 1 中国石油大学地球科学与技术学院 山东青岛 266555;2中国石化中原油田博士后工作站 河南濮阳 457001;3 中国石油大港油田公司勘探开发研究院 天津 300280
  • 收稿日期:2011-07-06 修回日期:2011-09-20 出版日期:2012-01-25 发布日期:2012-03-22
  • 通讯作者: 陈世悦
  • 作者简介:陈世悦,男,1963年4月生,1984年毕业于西安矿业学院,现为中国石油大学(华东)地球科学与技术学院教授、博士生导师,研究方向为沉积学及岩相古地理学。
  • 基金资助:

    中国石油天然气股份有限公司项目(07-01C-01-04)资助。

The saline genesis of lacustrine basin in the lower section of the first member of Shahejie Formation in Qikou Sag

CHEN Shiyue 1 WANG Ling 1 LI Cong 2 PU Xiugang 3 SUN Tingbin 1   

  • Received:2011-07-06 Revised:2011-09-20 Online:2012-01-25 Published:2012-03-22

摘要:

歧口凹陷沙河街组一段下亚段(简称沙一下亚段)在整体湖扩的背景下形成了多套薄层白云岩发育于暗色泥岩的特殊岩性段,显示出较强的咸化湖盆环境。对研究区内不同岩性样品进行的微量元素分析结果表明,歧口凹陷沙一下亚段主要为盐度较大的咸水环境;碳、氧稳定同位素测试显示该区碳酸盐岩δ13C 偏正异常明显,Z值分布范围为111~168.52;锶稳定同位素分布范围略高于同期海水,远低于同期河、湖水。结合薄片观察中发现的具指相意义的海绿石、胶磷矿,扫描电镜下发现的钙质超微化石研究表明,歧口凹陷沙一下亚段湖盆咸化可能是海侵所致。

关键词: 歧口凹陷, 沙一下亚段, 咸化湖盆, 海侵, 微量元素, 同位素

Abstract:

The lower sub-segment Es1 in the Qikou Sag formed a specific lithology of several sets of thin bed of dolomite developed in dark sandstone during the overall expansion of the lake, which showed a strong brackish lacustrine environment. The author studied the trace element of different lithology and the results tasted that the intended interval is mainly the saltwater atmosphere with large salinity. The carbon and oxygen stable isotope test displayed that the carbonate δ13C tended to positive anomaly and the  Z  value distributed between 111~168.52; the allocation for strontium stable isotopes is slightly higher than the same period sea and far lower than the river and lake; the study indicated that brackish lake basin maybe caused by marine transgression after combined with the diagnostic glauconite and collophane found in the phase and the calcareous nannofossils discovered in the SEM.

Key words: Qikou Sag, the lower section of the first member of Shahejie Formation, saline lacustrine basin, transgression, trace element, isotope