摘要
选定东营凹陷牛38、郝科1和利1等3口井东营组进行天文地层研究。以牛38井沙河街组一段顶界31.8Ma作为东营组底界年龄,得到3口井各段的年龄平均值为:东二段底28.406Ma,东一段底25.385Ma和顶界24.467Ma。东营组底界(31.829Ma)大致相当于"中国区域地层表"提出的32Ma的渐新统底年龄,但是与"国际地层表"提出的渐新世鲁培尔阶底界(33.9Ma)相差1.9Myr。东三段底界、顶界的平均年龄分别为31.829Ma、28.406Ma大致可与中国的乌兰布拉格阶或国际的鲁培尔阶中上部相当;东二段底界至东一段顶界的平均年龄大致相当于塔本布鲁克阶或夏特阶。根据东营组岩石地层与天文地层研究认为,在三角洲沉积过程中,东营组各段界线是穿时的,如东三与东二段界线的年龄相差可达1.4Myr。根据偏心率理论曲线和小波分析,夏特阶底界(28.4Ma)附近的变化可能与偏心率100ka左右理论周期的特殊变化有关。
Niu 38, Haoke 1, and Li 1 wells are selected for the astrostratigraphic study of the Dongying Formation in the Dongying Depression. The top boundary (31.8Ma) of the Member 1 of Shahejie Formation in Well Niu 38 is used as the basal boundary age of the Dongying Formation. The average values of each member of the three wells are determined to be: base of the Member 2 of Dongying Formation being 28.406Ma, base of the Member 1 of Dongying Formation being 25.385Ma, and its top boundary being 24.467Ma . The basal boundary of the Dongying Formation(31.829Ma)is roughly corresponding to the age (32Ma) in the 'Regional Stratigraphic Chart of China' , but it has 1.9Myr lag behind the basal boundary age (33.9Ma) of the Rupelian Stage. The average ages of basal and top boundaries of the Member 3 of Dongying Formation are 31.829Ma and 28.406Ma, roughly corresponding to upper—middle part of China's Wulanbulagean Stage or the Rupelian Stage. The average ages of basal boundary Member 2 and top boundary of Member 1 of Dongying Formation are roughly corresponding to the Tabenbulukian or Chattion Stage. The lithostratigraphic and astrostratigraphic study for the Dongying Formation shows that during the deposition of delta, the boundaries of all members of the Dongying Formation are diachronous, e.g. the time difference of boundaries between the Member 3 and Member 2 of Dongying Formation reaches up to 1.4Myr . According to the theoretical curve of eccentricity and wavelet analysis, the variation near the basal boundary of the Chattian Stage (28.4Ma) may be related to the special pattern of theoretical 100ka period of eccentricity.
出处
《地层学杂志》
CSCD
北大核心
2007年第S2期471-482,共12页
Journal of Stratigraphy
基金
中石化"东营凹陷成烃成藏定量研究"课题
国家自然科学主任基金项目(No40542007)资助
关键词
天文地层
小波分析
东营组
渐新统
古近系
东营凹陷
山东
astrostratigraphy, wavelet analysis, Dongying Formation, Oligocene, Palaeogene, Dongying Depression, Shandong Province
